BraveSirRobbin
Moderator
[How-To] Build the Ultimate Garage Door Monitor
by BraveSirRobbin
One critical monitoring element for any home automation system is the garage door. There are many ways to do this including using your traditional magnetic contacts which will change state when the garage door is open or closed. This method satisfies the minimal requirement of knowing the open/close status of the garage door. But what happens if more detail about the garage door is needed? For instance what can you do if you would like to know the exact position of the door (say if it got stuck during its open/close travel)? What if you wanted to know this garage door position to within a few inches?
EDIT: One note I would like to make based on some of the replies below. This is the ADVANCED ULTIMATE method of monitoring your garage door's EXACT status/position. If all you want are simple and basic OPEN, CLOSE, and maybe one IN-BETWEEN state, then go get yourself some wide gap magnetic contacts and X-10 Powerflash modules and do not bother reading any further! :lol:
Edit2: This article is also published in HomeToys.com February 2006 Edition.
First our general disclaimer:
CocoonTech.com and its staff is NOT responsible for any damage or liability caused by anyone following, building, or admiring any steps in the following document.
Background
There have been many posts on various forums on how to do this including using multiple magnetic contacts which open or short a chain of resistors in series. Thus when you bias this series chain with a voltage you will get a different voltage output depending on what magnetic contact the door has just passed. The problem with this method is that the resistor doesn't stay open or shorted; it'ss just a momentary situation as the door passes the contact. Plus the contacts would be a pain to install on your garage doors tract. Also your resolution of knowing the exact position of the garage door would depend on the number of magnetic contacts installed.
This How-To will describe a way to monitor your garage doors position using a ten turn rotary potentiometer and an analog to digital (A-D) converter. The end product will yield a voltage output that is proportional to the garage door's position; therefore the resolution or accuracy would highly depend on the analog to digital converter used.
Theory
I initially came up with this idea by studying exactly what moves with the garage door when it opens and closes. I noticed that the metal pipe which holds the garage doors large coiled spring (over the top length of the garage door) turns multiple times as the garage door is moving (see below). Of course, if your garage door does not operate in a way that has a rotating pipe, this method may not work without alterations.
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Inside View of Garage Door
I marked the pipe with a marker and counted the number of times the pipe rotated during the entire garage door travel from open to close. Mine rotated between six and seven times. I also noticed that the end of the pipe was hollow.
Well, this had me thinking about a way to monitor this rotary movement as it should be linear with the garage doors travel. In other words the amount of times the pipe rotated can be compared to the amount the garage door has opened (more on this later).
I already had a 10-bit analog to digital converter from PH Anderson incorporated into my home automation system. I now needed to somehow mount something on that pipe that would change a voltage (linearly) as it turned. Since the end of the pipe was opened (i.e. not a solid end) I elected to use a ten turn rotary potentiometer for this purpose. The potentiometer (pot) would not get bound up as the pipe only turned less than six rotations (and the pot incorporates ten turns). Also, the one I had laying around was a good Bourns ten-turn, wire wound, linear pot whose value went from zero to 100 ohms as the center shaft rotated. The Bourns part number is 3540s-1-101-ND.
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Bourns Ten-Turn Potentiometer
You can obtain this pot from DigiKey (enter that part number in their part search dialog box on their main site). Their price is $13.38 plus shipping.
Methodology
In order to get a voltage value from this potentiometer a DC Power Supply is needed to supply a bias voltage. Thus as the shaft of the pot turns the pots output voltage would vary. This voltage would then be measured with an analog to digital converter, thus converting this voltage to a bit number whose value would correspond with the voltage reading. This bit value would then be converted to inches via home automation software.
You may want to reference THIS How-To for detailed information on how analog to digital converters work and how to formulate equations to obtain real world (in this case inches) numbers into your home automation system.
The monitoring methodology would thus be:
There are a couple of variables here that need to be mentioned depending on your integration hardware you are planning to use. For instance in my case, the PH Anderson analog to digital converter can only accept a maximum of five volts for its channels input value. This will influence the maximum voltage that I will excite the potentiometer with.
Another factor to consider is that this is a hardwired system. In other words you need at least one pair of wires to go from the potentiometer to wherever your analog to digital converter is mounted. Since this wire length may be substantial it is a good idea to also tailors your potentiometers bias voltage setting so it outputs the maximum permissible value during the entire travel length of the garage door (i.e. bias with the highest allowable voltage value). This will also keep noise influence to a minimum as well as increase accuracy of the system (I noticed that my analog to digital converter was slightly non-linear for very low voltage levels).
Let me explain this step in detail as it is important. I wanted a maximum reading of five volts for my analog to digital converter since this was its maximum permissible input as stated above. I have a lot of DC voltage wall warts that I accumulated over the years (voltage converters that you plug into your wall to operate small electronic devices).
I selected a wall wart that stated a 5 volt output. I then wired this up to my potentiometer as shown below. Note that an in-line fuse was added for safety, even though you are dealing with very small DC voltage levels. These in-line fuse holders can be purchased from a variety of sources including Radio Shack.
Since I am using a 5 volt supply and biasing a 100 ohm potentiometer, the current I will draw from the wall wart is calculated using the equation:
Current = Voltage / Resistance, or 5/100, which equals 0.05 amps (50 milliamps).
Therefore you can select a very small fuse for your in-line fuse holder.
The power that will be dissipated by the potentiometer is calculated using the equation:
Power = Voltage * Current, or 5 * 0.05, which equals 0.25 watts (one-quarter watt). Note that the potentiometer I selected will handle up to two watts.
I then bench tested the potentiometer, wall wart, and fuse holder by wiring them according to the schematic below.
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Schematic Diagram
This setup was then tested by connecting a DC voltmeter on the potentiometer's output connections (as shown on the schematic). As the potentiometer turns the voltage should change accordingly.
You may want to also perform a quick test of your analog to digital converter by connecting the output of the potentiometer to your analog to digital converter's input channel and see if the corresponding bit output from the computer screen correlates properly with the voltage measured by the meter. This would give you a feel for how to use your analog to digital converter as well as test its linearity.
If you need additional information on how to convert from bits measured by the analog to digital converter to a voltage value (or vice versa) please refer to my guide on Analog to Digital Converters. I would also plot your results as a double check that a straight line can be drawn between your data points in order to verify linearity. More on this later below.
Now you need to determine whether you need a clockwise or counterclockwise rotation on the shaft of the potentiometer to increase your voltage output. Carefully watch the pipe above the garage and note which direction it turns when the garage door opens. Also watch with closer accuracy on how many rotations are used. I wanted the voltage to increase as the garage door was opened, but either way would work.
After you get a feel for how this works you may want to determine the shaft's "turn" position that you want the potentiometer to be at when the garage door is opened (i.e. the voltage that the potentiometer will read when the garage door is fully opened). The way I determined this is that I rotated the potentiometers shaft till I obtained the maximum (limited out) voltage output reading from the meter as connected in the above described test. I then backed off a little less then a half turn. I then noted the output voltage to insure that this reading was below the maximum allowable input of my analog to digital converter.
If the reading is to high, back off on the potentiometer until you get below this value (for me it was five volts maximum input so I had the potentiometer read 4.90 volts). This not only insured that I would never get above my maximum voltage, but also insured that I had enough play or rotation length left in the pot so that I would never be able to bind the pot when the garage door was in its maximum open position. Also note that I wanted to get somewhere in the ballpark of over four volts since I wanted to have a reading well above the noise level when the garage was lowered.
You can test this value as well by turning the pot the maximum number of rotations that your garage door pipe rotates and see what this value would be. Since we know that this is a ten turn pot and that the garage pipe rotates a number well under ten, there is no way that we would be able to bind the pot past its lower position when the garage door closed.
Note these upper and lower (garage door opened and closed) potentiometer values for later reference.
This is why we tested both the travel and maximum voltage the pot would see when the garage door is in the opened position (important knowledge for when we mount the pot to the pipe end).
Turn the potentiometer to this new garage door opened position and maybe even put a piece of tape between the pot and its shaft to keep this position in place. During the course of following the hardware installation instructions below, you can always double check this reading/position.
Hardware Installation
I purchased some solid rubber corks/stoppers/plugs from my local hardware store (Home Depot). This rubber plug will be used to mount the shaft of the potentiometer to the end of the hollow round pipe that turns when the garage door moves. The rubber plug that I wound up using was one inch long in length and had a one inch diameter on its larger round end. HERE has an excellent selection of rubber plugs of various sizes AND they will even send you a free sample on request ! This rubber plug would then be jammed inside the end of the pipe as pictured below.
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Testing Rubber Stopper's Fit
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Rubber Stopper Mounted on Pipe
Now that you know the rubber stopper will mount properly to the pipes end its time to work on interfacing it to the potentiometers shaft. To do this I selected a drill bit whose diameter was slightly undersized from the pots shaft diameter. I then drilled a hole in the large diameter end of the rubber stopper as shown below. It is VERY important to make sure this hole is centered on the rubber stoppers round end.
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Drilling Hole in Rubber Cork
Now that the hole is drilled test fit the potentiometer by inserting its shaft into the rubber stopper's end. This fit needs to be very snug so no slipping can occur between the rubber cork and the shaft. You can always go with a larger drill bit if the shaft just will not fit.
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Pot Mounted to Rubber Cork
Now solder long wire leads to each of the potentiometers connections referencing the above schematic. Use shrink tubing over the connections and wire ends. Insure that you have the proper clockwise/counterclockwise selections for connections 1 and 3. Note that you will probably need to use a nearby outlet for the wall wart (unless you are running this voltage from the analog to digital converters location) so make your wire leads are long enough to reach. Also, use different color wire or mark the wire ends so you know which are the proper ones to use for the wall wart and which ones to use for the analog to digital converters input.
Obtain a 3/4 inch EMT metal conduit holder from a hardware store as shown below.
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Conduit Holder for Pot's Mount
Next, mount the potentiometer inside this conduit holder as shown below. Insure that the leads from the pot are isolated from the metal of the conduit holder. I had to slightly bend the back lead a bit.
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Pot Mounted to Conduit Holder
Now temporarily mount this unit to the garage doors pipe end using the rubber stopper as shown below.
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Test Mount to Pipe's End
To mount this pot/conduit holder to the garage door end, I used a metal mounting strap (same style/type of metal strap that is used to suspend my garage door opener unit from the ceiling) that I bent as shown below. You can take some measurements while the potentiometer/conduit holder is temporarily installed to see what means are needed. I elected to use the channel of the garage door directly below to mount this assembly to (via this mounting strap). I cut the strap to length, bent it 90 degrees in two places and then bolted the conduit holder onto the metal strap as shown below. The plethora of holes these straps provide make it easy to obtain a properly oriented mount to the garage doors upper pipe end.
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Final Mount/Holder
Now make sure the rubber stopper is jammed tightly into the garage doors pipe end. I used a rubber mallet. OPEN the garage door.
Insure the potentiometers shaft position is at the same garage door opened position during your testing above (you did place a piece of tape on it right?).
Install the above assembly onto the garage door channel and rubber stopper. Insure that the unit is centered with the pipe and that the pots shaft is fully inserted into the rubber stopper. Some fine tuning may be necessary in order to accomplish this by adjusting the bends of the metal strapping used to mount the pot/conduit holder to the garage doors channel.
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Product Mounted to Garage Frame
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Close up of Final Mount
Close the garage and note how this assembly travels. If excessive swaying back and forth occur, you may have to re-adjust the alignment to the pipe. If this does not work your hole placed in the rubber stopper may not be centered. The assembly will have a little play though the garage doors travel. This is why a rubber mounting method to the pipe shaft was chosen. Also, the metal strapping will let the assembly ride a certain distance up and down during the travel cycle as well.
Obtaining Data
Once you are satisfied with the way the potentiometer assembly is mounted to the pipe end you may now test the system by seeing how linear the relationship is between the potentiometers output and the bottom garage doors distance from the floor.
Connect a voltmeter (set to measure DC Volts) on the output of the potentiometer and then plug the wall wart into an AC outlet. Open the garage door and note the voltage on the meter. Close the garage door and note the voltage on the meter. Did it decrease as the garage door closed?
Now its time to take some data! You will do this by running the garage door to various stopped distances (above the floor) and record the distance the bottom of the garage door is from the floor along with the voltmeter reading (from the potentiometer) for that distance. Divide the garage door travel distance up to about eight different intervals, then move the bottom of the garage door to that interval and take a voltage reading as well as measure (in inches) the distance between the bottom of the garage door and the floor. Note that for my first test (pictured below) I just used a variable DC power supply instead of a wall wart (since I was just playing around to see if this concept worked). I did retake this data once I determined which exact wall wart I was going to use for the final installation though.
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Close up of Final Mount
To see how linear your data is you need to plot it on a graph. If a straight line can connect the data points, then you have a great linear relationship. This is important for when we determine an equation of this line in order to read total inches with our Home Automation software (more on this later).
The easiest way to plot numbers is to use Microsoft Excel, though you can just use regular graph paper as well. The table and graph below show my results.
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Data Set & Graph
Doing the Math
As you can see the line is fairly straight. If you did not obtain a straight line from your plotted results, you may want to retake the data. Other than that you may want to try to change your voltage (bias) range. Also, make sure the potentiometer and rubber stopper are not "slipping" while the door is in travel.
If the data line is not straight you will have difficulty solving for an equation to represent that line. An equation is needed in order to calculate the analog to digital voltage reading to an inch number via your home automation software.
Now you can create an equation to represent this line according to the instructions described in my Analog to Digital Converters guide. This equation would solve for distance (inches) when given a voltage value. You could then convert this voltage value to bits which are what would be read for your analog to digital input. In short a total calculation would convert bits to voltage to inches.
One easier way to do this conversion would be just to retake the data but connect the potentiometer to an input channel of your analog to digital converter and record BITS instead of VOLTAGE. In other words you would do the exact same test as above, but instead of taking a voltage reading from a DC meter, you would just record the raw bits from the computer that is connected to the analog to digital converter. This would prove both that your potentiometer output was linear AND that your analog to digital converter was linear at the same time.
Testing the Analog to Digital Converter
Connect your analog to digital converter to your computer via its proper interface. In my case using my PH Anderson A-D board, a serial port was used. This board will echo all eight channels of its outputs in raw bits after it receives any ASCII character from the serial port.
HyperTerminal was used to read the channel bit values. Power was also applied to the board. The proper baud and communication settings were made and a carriage return was sent to the board. Indeed the eight channel's bit values were echoed back on the computer screen.
I then retook the garage door data. I just hit a carriage return after moving the garage door to a certain level and read channel one's bit value. I then recorded this bit value along with the distance the garage door was from the floor. A plot was then made of the bit value vs. the garage doors position above the floor (in inches).
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Data Set & Graph
Again you can see that a straight line was obtained.
Finalize all of your wiring and routing and mount your analog to digital converter and connect it permanently to your home automation computer. Insure all wires are routed properly so they do not interfere with any garage door operation. Connect the potentiometer output wires to the analog input channel. Plug the wall wart into its designated outlet.
Develop the Software Interface
Now that you are finished with the hardware interface it is time to work on the software. This software will convert the bits displayed on your analog to digital converter to inches (that the garage door bottom is above the floor).
Again please reference the Analog to Digital Converters guide as the following instructions are abridged below.
If you have any problems with the instructions below, please post your data obtained and I'll help you through the rest of this procedure.
The slope intercept formula of Y = mX + b will be used with Y being the bit value and X being the inches the garage door is from the floor value.
To solve for m (slope) and b (Y intercept) we need to select two data points from the graph above. I like to select two data points just inside the max and min values so the following points (X, Y Pairs) will be used (again these values are read directly off of the data graph/chart above).
10.5, 276
68, 856
Solve for m using the equation:
m = (Y2-Y1) / (X2-X1) or (856-276) / (68-10.5) or 580 / 57.5 or 10.087
The b intercept can be calculated using Y = mX + b and substitute the m value above with the first data point used (in this case 10.5, 276).
276 = 10.087 (10.5) + b
Solving for b yields b = 276-(10.087 * 10.5) or 161.865
So now our equation can be represented by:
Y = mX + b
Y = 10.087X + 161.865
Since Y represents BITS and X represents INCHES, we can rewrite this equation as follows:
BITS = 10.087 (INCHES) + 161.865
Since we will know the BITS from the Analog to Digital converter, we must solve the above equation for INCHES (the unknown variable). Rearranging the above equation yields:
INCHES = (BITS-161.865) / 10.087 or
INCHES = 0.099 * BITS-16.05
Test this calculation by using another X,Y pair from the graph above. Lets take the pair 57,752.
If we use the equation above to solve for INCHES knowing the BIT number we get
INCHES = 0.099 * 752-16.05 which yields 58.4 which is pretty close to 57 (the corresponding X value).
Lets further test this calculation using another X,Y pair from the data above. This time lets use pair 20.5, 375.
INCHES = 0.099 * BITS-16.05
INCHES = 0.099 * 375-16.05, which yields 21.08 which is pretty close to 20.5 (its corresponding X value).
Final Accuracy Test
Now that you can convert a bit number from the analog to digital converter to real world inches, test the final accuracy of your measurement system. Move the garage door to a position say 1/3 of the way open. Read the bit value from the analog to digital converter. Using the above equation INCHES = 0.099 * BITS-16.05, calculate the expected inches result. Then measure the actual distance the bottom of the garage door is from the floor and it should match this value very closely.
Continue this test for other open stages of the garage door (say 1/2. 2/3, and 3/4 open). Also check the fully closed and fully open positions. These results will let you know the relative accuracy you can expect for your system.
Please note that several factors will determine the accuracy and repeatability of your system, most importantly the total bits of your analog to digital converter. If you have an eight bit converter vs. a ten bit your resolution would be less and repeatable results would be more sporadic (though within a certain window range). Again, please refer to the guide Analog to Digital Converters for further details.
The PH Anderson Analog to Digital Converter
As mentioned earlier, I am using THIS PH Anderson eight channel 10-bit analog to digital converter. The unit is $40 plus $6 shipping. I also emailed Mr. Anderson and asked for a version so all of the eight channels of bit data is in one line, rather than the two separate lines as shown in its literature. This made the serial program to retrieve the specific bit channels of data a lot easier to write.
The main advantage this unit has over other analog to digital converters included in the Ocelots SECU16 and the Elk M1 Gold is its ten bit accuracy vs. just the eight bits included with those other two systems. Again, refer to the Analog to Digital Converters guide for additional details as to why this may or may not be important for your application. I also wanted the additional ten bit resolution channels for other projects as well. I would also like to add that I found corresponding with Mr. Anderson via email to be a very pleasant experience.
Integrating With Home Automation Software
I currently use HomeSeer ver 1.7.43 with MainLobby for my visual displays. In order to integrate the PH Anderson Analog to Digital Converter I had to create a couple of scripts. These scripts also incorporated the equation determined above which converted the bit number to inches that the bottom of the garage door was above the floor.
First, two scripts are required for the PH Anderson Analog to Digital Converter. One script sets up the serial port and polling, and the other actually acquires the data from the channels.
I currently have the PH Andersons board on serial port number ten, but had to use serial port number threes resources. This is partly because I have two on-board serial ports on my HomeSeers computer and also incorporate an Edgeport 8 serial expander. The serial ports start at Com1 and Com2 for the on-board motherboards ports, but then skip to Com5, Com6, Com7, Com8, Com9, Com10, Com11, and Com12 for the Edgeports serial ports. I simply could not get any programs working within HomeSeer using any OpenComPort or CloseComPort with that higher serial port number (so I therefore used Com Port 3 resources since Com3 and Com4 were not used in my system).
I created HomeSeer devices (device type interface variable) R1 through R8 which will represent the value of the eight channels of the PH Anderson Analog to Digital Converter.
To set this serial interface up I incorporated the following VB Script below. Note that two resources I found handy while writing this code were ASCII Lookup Tables and Microsoft's Visual Basic Scripting Guide.
This program opens the com port, calls the subroutine Fran in the analogdatanew.txt script (which it will pass the data to), then sends an ASCII character 100 (any ASCII character will do) to the A-D board so it will echo the data back via the serial port.
I then setup an event in HomeSeer which runs every 20 seconds that calls the above script (as shown below). The timing of the run cycle will depend on your specific application.
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HomeSeer Event Setup
The details of the analogdatanew.txt script are listed below:
Note that HomeSeer device R1 will now contain the inches the garage door is from the floor. Also note that this value was written in the device value and string as well.
Also, for what it's worth, notice that I have an LM34 temperature probe installed on channel 8 of the PH Anderson Analog to Digital converter and show the necessary calculation to convert this reading to degrees F which is written to the HomeSeer device R8 (showing the versatility of this A-D board).
Well now we have a HomeSeer device which shows the value in inches, but wouldnt it be nice to know the percent the garage door is opened? In other words is the garage door half-way open, 80% open, etc. This may be more useful than knowing the actual inches.
This percentage number is easy to calculate. When my garage door is fully opened the bottom of the door is 83 inches from the floor. This represents being 100 percent opened. Of course when the garage door is closed its bottom is (approximately) zero inches from the floor. This represents zero percent opened. Now we need to express the actual inches measured as a percentage based on these two limits. To do this we need to divide the inch reading from the maximum 83 inch number, then multiply that result by 100. In other words the equation would be:
Percent Open = Inches / 83 * 100
I also created a HomeSeer interface variable device R9 which will represent this percent open number. The code is incorporated below (gdpercent is the variable that represents this percent open value).
Wow, we now have two HomeSeer devices which show garage door monitor information. One device (R1) shows the actual inches the bottom of the garage door is from the floor. The other device (R9) displays the percent open or the percentage the garage door is opened.
You can now use these values to trigger other events or code as you wish. For instance you may want to trigger an event which calls you after a certain amount of time after you open or close the garage door in case it doesnt open or close fully (garage door opener gets jammed).
Since I have MainLobby incorporated into my HomeSeer automation system, I wanted a cool display which represented exactly where the garage door was or in other words, graphically show its percent open condition. I could do this very easily by showing the percent open number as a variable for a slider, but this did not look much like a garage door.
Well, my MainLobby friend Fungun (aka Tim) came to my rescue by making a series of garage door jpg images (11 total) which showed a white, double car garage door in various stages of open. I renamed these images as garage1.jpg (fully opened), garage10.jpg (10% open), garage20.jpg (20% open), etc. all the way up to garage100.jpg (fully opened). Now all I have to do is pass the "garage door percent" HomeSeer device value as a variable to Main Lobby (range), then do a condition statement based on the value of this device and display the proper jpg on my Main Lobby scene.
The code which incorporates this feature is shown below.
I copied all of the garage jpg images into my cinemar/images directory. I then created a library button on my MainLobby scene and pointed its label to this range variable.
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MainLobby Button Dialog Settings
The results of this MainLobby display are shown below. I would like to again thank Fungun for creating these images for me.
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Scene With Garage Door 20% Open
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Scene With Garage Door 50% Open
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Scene With Garage Door 80% Open
Conclusion
That concludes this How-To on building the ultimate garage door monitor. Remember, any amateur home automation enthusiast can tell you if the garage door is open or closed based on magnetic contact sensors, but a REAL HA person can tell you within a few inches the EXACT position of the garage door itself!!
Why do you need to know this information, well, because you now CAN!!
My setup has been working for months and it is nice to know the position of the door, especially in the summer months when we crack this door to let some air in. Also, many people have expressed this interest because they occasionally have their garage door openers jam, and come home to an open door at the end of their work day!
As always please feel free to provide comments and suggestions below!
by BraveSirRobbin
One critical monitoring element for any home automation system is the garage door. There are many ways to do this including using your traditional magnetic contacts which will change state when the garage door is open or closed. This method satisfies the minimal requirement of knowing the open/close status of the garage door. But what happens if more detail about the garage door is needed? For instance what can you do if you would like to know the exact position of the door (say if it got stuck during its open/close travel)? What if you wanted to know this garage door position to within a few inches?
EDIT: One note I would like to make based on some of the replies below. This is the ADVANCED ULTIMATE method of monitoring your garage door's EXACT status/position. If all you want are simple and basic OPEN, CLOSE, and maybe one IN-BETWEEN state, then go get yourself some wide gap magnetic contacts and X-10 Powerflash modules and do not bother reading any further! :lol:
Edit2: This article is also published in HomeToys.com February 2006 Edition.
First our general disclaimer:
CocoonTech.com and its staff is NOT responsible for any damage or liability caused by anyone following, building, or admiring any steps in the following document.
Background
There have been many posts on various forums on how to do this including using multiple magnetic contacts which open or short a chain of resistors in series. Thus when you bias this series chain with a voltage you will get a different voltage output depending on what magnetic contact the door has just passed. The problem with this method is that the resistor doesn't stay open or shorted; it'ss just a momentary situation as the door passes the contact. Plus the contacts would be a pain to install on your garage doors tract. Also your resolution of knowing the exact position of the garage door would depend on the number of magnetic contacts installed.
This How-To will describe a way to monitor your garage doors position using a ten turn rotary potentiometer and an analog to digital (A-D) converter. The end product will yield a voltage output that is proportional to the garage door's position; therefore the resolution or accuracy would highly depend on the analog to digital converter used.
Theory
I initially came up with this idea by studying exactly what moves with the garage door when it opens and closes. I noticed that the metal pipe which holds the garage doors large coiled spring (over the top length of the garage door) turns multiple times as the garage door is moving (see below). Of course, if your garage door does not operate in a way that has a rotating pipe, this method may not work without alterations.
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Inside View of Garage Door
I marked the pipe with a marker and counted the number of times the pipe rotated during the entire garage door travel from open to close. Mine rotated between six and seven times. I also noticed that the end of the pipe was hollow.
Well, this had me thinking about a way to monitor this rotary movement as it should be linear with the garage doors travel. In other words the amount of times the pipe rotated can be compared to the amount the garage door has opened (more on this later).
I already had a 10-bit analog to digital converter from PH Anderson incorporated into my home automation system. I now needed to somehow mount something on that pipe that would change a voltage (linearly) as it turned. Since the end of the pipe was opened (i.e. not a solid end) I elected to use a ten turn rotary potentiometer for this purpose. The potentiometer (pot) would not get bound up as the pipe only turned less than six rotations (and the pot incorporates ten turns). Also, the one I had laying around was a good Bourns ten-turn, wire wound, linear pot whose value went from zero to 100 ohms as the center shaft rotated. The Bourns part number is 3540s-1-101-ND.
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Bourns Ten-Turn Potentiometer
You can obtain this pot from DigiKey (enter that part number in their part search dialog box on their main site). Their price is $13.38 plus shipping.
Methodology
In order to get a voltage value from this potentiometer a DC Power Supply is needed to supply a bias voltage. Thus as the shaft of the pot turns the pots output voltage would vary. This voltage would then be measured with an analog to digital converter, thus converting this voltage to a bit number whose value would correspond with the voltage reading. This bit value would then be converted to inches via home automation software.
You may want to reference THIS How-To for detailed information on how analog to digital converters work and how to formulate equations to obtain real world (in this case inches) numbers into your home automation system.
The monitoring methodology would thus be:
- Mount the rotary potentiometer on the end of the pipe as mentioned above
- Wire a DC Power Supply to the coil sides of the potentiometer
- Monitor the output voltage of the pot with an analog to digital converter
- Supply an algorithm (equation) to convert this voltage to inches (that the garage door is opened).
There are a couple of variables here that need to be mentioned depending on your integration hardware you are planning to use. For instance in my case, the PH Anderson analog to digital converter can only accept a maximum of five volts for its channels input value. This will influence the maximum voltage that I will excite the potentiometer with.
Another factor to consider is that this is a hardwired system. In other words you need at least one pair of wires to go from the potentiometer to wherever your analog to digital converter is mounted. Since this wire length may be substantial it is a good idea to also tailors your potentiometers bias voltage setting so it outputs the maximum permissible value during the entire travel length of the garage door (i.e. bias with the highest allowable voltage value). This will also keep noise influence to a minimum as well as increase accuracy of the system (I noticed that my analog to digital converter was slightly non-linear for very low voltage levels).
Let me explain this step in detail as it is important. I wanted a maximum reading of five volts for my analog to digital converter since this was its maximum permissible input as stated above. I have a lot of DC voltage wall warts that I accumulated over the years (voltage converters that you plug into your wall to operate small electronic devices).
I selected a wall wart that stated a 5 volt output. I then wired this up to my potentiometer as shown below. Note that an in-line fuse was added for safety, even though you are dealing with very small DC voltage levels. These in-line fuse holders can be purchased from a variety of sources including Radio Shack.
Since I am using a 5 volt supply and biasing a 100 ohm potentiometer, the current I will draw from the wall wart is calculated using the equation:
Current = Voltage / Resistance, or 5/100, which equals 0.05 amps (50 milliamps).
Therefore you can select a very small fuse for your in-line fuse holder.
The power that will be dissipated by the potentiometer is calculated using the equation:
Power = Voltage * Current, or 5 * 0.05, which equals 0.25 watts (one-quarter watt). Note that the potentiometer I selected will handle up to two watts.
I then bench tested the potentiometer, wall wart, and fuse holder by wiring them according to the schematic below.
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Schematic Diagram
This setup was then tested by connecting a DC voltmeter on the potentiometer's output connections (as shown on the schematic). As the potentiometer turns the voltage should change accordingly.
You may want to also perform a quick test of your analog to digital converter by connecting the output of the potentiometer to your analog to digital converter's input channel and see if the corresponding bit output from the computer screen correlates properly with the voltage measured by the meter. This would give you a feel for how to use your analog to digital converter as well as test its linearity.
If you need additional information on how to convert from bits measured by the analog to digital converter to a voltage value (or vice versa) please refer to my guide on Analog to Digital Converters. I would also plot your results as a double check that a straight line can be drawn between your data points in order to verify linearity. More on this later below.
Now you need to determine whether you need a clockwise or counterclockwise rotation on the shaft of the potentiometer to increase your voltage output. Carefully watch the pipe above the garage and note which direction it turns when the garage door opens. Also watch with closer accuracy on how many rotations are used. I wanted the voltage to increase as the garage door was opened, but either way would work.
After you get a feel for how this works you may want to determine the shaft's "turn" position that you want the potentiometer to be at when the garage door is opened (i.e. the voltage that the potentiometer will read when the garage door is fully opened). The way I determined this is that I rotated the potentiometers shaft till I obtained the maximum (limited out) voltage output reading from the meter as connected in the above described test. I then backed off a little less then a half turn. I then noted the output voltage to insure that this reading was below the maximum allowable input of my analog to digital converter.
If the reading is to high, back off on the potentiometer until you get below this value (for me it was five volts maximum input so I had the potentiometer read 4.90 volts). This not only insured that I would never get above my maximum voltage, but also insured that I had enough play or rotation length left in the pot so that I would never be able to bind the pot when the garage door was in its maximum open position. Also note that I wanted to get somewhere in the ballpark of over four volts since I wanted to have a reading well above the noise level when the garage was lowered.
You can test this value as well by turning the pot the maximum number of rotations that your garage door pipe rotates and see what this value would be. Since we know that this is a ten turn pot and that the garage pipe rotates a number well under ten, there is no way that we would be able to bind the pot past its lower position when the garage door closed.
Note these upper and lower (garage door opened and closed) potentiometer values for later reference.
This is why we tested both the travel and maximum voltage the pot would see when the garage door is in the opened position (important knowledge for when we mount the pot to the pipe end).
Turn the potentiometer to this new garage door opened position and maybe even put a piece of tape between the pot and its shaft to keep this position in place. During the course of following the hardware installation instructions below, you can always double check this reading/position.
Hardware Installation
I purchased some solid rubber corks/stoppers/plugs from my local hardware store (Home Depot). This rubber plug will be used to mount the shaft of the potentiometer to the end of the hollow round pipe that turns when the garage door moves. The rubber plug that I wound up using was one inch long in length and had a one inch diameter on its larger round end. HERE has an excellent selection of rubber plugs of various sizes AND they will even send you a free sample on request ! This rubber plug would then be jammed inside the end of the pipe as pictured below.
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Testing Rubber Stopper's Fit
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Rubber Stopper Mounted on Pipe
Now that you know the rubber stopper will mount properly to the pipes end its time to work on interfacing it to the potentiometers shaft. To do this I selected a drill bit whose diameter was slightly undersized from the pots shaft diameter. I then drilled a hole in the large diameter end of the rubber stopper as shown below. It is VERY important to make sure this hole is centered on the rubber stoppers round end.
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Drilling Hole in Rubber Cork
Now that the hole is drilled test fit the potentiometer by inserting its shaft into the rubber stopper's end. This fit needs to be very snug so no slipping can occur between the rubber cork and the shaft. You can always go with a larger drill bit if the shaft just will not fit.
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Pot Mounted to Rubber Cork
Now solder long wire leads to each of the potentiometers connections referencing the above schematic. Use shrink tubing over the connections and wire ends. Insure that you have the proper clockwise/counterclockwise selections for connections 1 and 3. Note that you will probably need to use a nearby outlet for the wall wart (unless you are running this voltage from the analog to digital converters location) so make your wire leads are long enough to reach. Also, use different color wire or mark the wire ends so you know which are the proper ones to use for the wall wart and which ones to use for the analog to digital converters input.
Obtain a 3/4 inch EMT metal conduit holder from a hardware store as shown below.
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Conduit Holder for Pot's Mount
Next, mount the potentiometer inside this conduit holder as shown below. Insure that the leads from the pot are isolated from the metal of the conduit holder. I had to slightly bend the back lead a bit.
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Pot Mounted to Conduit Holder
Now temporarily mount this unit to the garage doors pipe end using the rubber stopper as shown below.
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Test Mount to Pipe's End
To mount this pot/conduit holder to the garage door end, I used a metal mounting strap (same style/type of metal strap that is used to suspend my garage door opener unit from the ceiling) that I bent as shown below. You can take some measurements while the potentiometer/conduit holder is temporarily installed to see what means are needed. I elected to use the channel of the garage door directly below to mount this assembly to (via this mounting strap). I cut the strap to length, bent it 90 degrees in two places and then bolted the conduit holder onto the metal strap as shown below. The plethora of holes these straps provide make it easy to obtain a properly oriented mount to the garage doors upper pipe end.
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Final Mount/Holder
Now make sure the rubber stopper is jammed tightly into the garage doors pipe end. I used a rubber mallet. OPEN the garage door.
Insure the potentiometers shaft position is at the same garage door opened position during your testing above (you did place a piece of tape on it right?).
Install the above assembly onto the garage door channel and rubber stopper. Insure that the unit is centered with the pipe and that the pots shaft is fully inserted into the rubber stopper. Some fine tuning may be necessary in order to accomplish this by adjusting the bends of the metal strapping used to mount the pot/conduit holder to the garage doors channel.
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Product Mounted to Garage Frame
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Close up of Final Mount
Close the garage and note how this assembly travels. If excessive swaying back and forth occur, you may have to re-adjust the alignment to the pipe. If this does not work your hole placed in the rubber stopper may not be centered. The assembly will have a little play though the garage doors travel. This is why a rubber mounting method to the pipe shaft was chosen. Also, the metal strapping will let the assembly ride a certain distance up and down during the travel cycle as well.
Obtaining Data
Once you are satisfied with the way the potentiometer assembly is mounted to the pipe end you may now test the system by seeing how linear the relationship is between the potentiometers output and the bottom garage doors distance from the floor.
Connect a voltmeter (set to measure DC Volts) on the output of the potentiometer and then plug the wall wart into an AC outlet. Open the garage door and note the voltage on the meter. Close the garage door and note the voltage on the meter. Did it decrease as the garage door closed?
Now its time to take some data! You will do this by running the garage door to various stopped distances (above the floor) and record the distance the bottom of the garage door is from the floor along with the voltmeter reading (from the potentiometer) for that distance. Divide the garage door travel distance up to about eight different intervals, then move the bottom of the garage door to that interval and take a voltage reading as well as measure (in inches) the distance between the bottom of the garage door and the floor. Note that for my first test (pictured below) I just used a variable DC power supply instead of a wall wart (since I was just playing around to see if this concept worked). I did retake this data once I determined which exact wall wart I was going to use for the final installation though.
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Close up of Final Mount
To see how linear your data is you need to plot it on a graph. If a straight line can connect the data points, then you have a great linear relationship. This is important for when we determine an equation of this line in order to read total inches with our Home Automation software (more on this later).
The easiest way to plot numbers is to use Microsoft Excel, though you can just use regular graph paper as well. The table and graph below show my results.
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Data Set & Graph
Doing the Math
As you can see the line is fairly straight. If you did not obtain a straight line from your plotted results, you may want to retake the data. Other than that you may want to try to change your voltage (bias) range. Also, make sure the potentiometer and rubber stopper are not "slipping" while the door is in travel.
If the data line is not straight you will have difficulty solving for an equation to represent that line. An equation is needed in order to calculate the analog to digital voltage reading to an inch number via your home automation software.
Now you can create an equation to represent this line according to the instructions described in my Analog to Digital Converters guide. This equation would solve for distance (inches) when given a voltage value. You could then convert this voltage value to bits which are what would be read for your analog to digital input. In short a total calculation would convert bits to voltage to inches.
One easier way to do this conversion would be just to retake the data but connect the potentiometer to an input channel of your analog to digital converter and record BITS instead of VOLTAGE. In other words you would do the exact same test as above, but instead of taking a voltage reading from a DC meter, you would just record the raw bits from the computer that is connected to the analog to digital converter. This would prove both that your potentiometer output was linear AND that your analog to digital converter was linear at the same time.
Testing the Analog to Digital Converter
Connect your analog to digital converter to your computer via its proper interface. In my case using my PH Anderson A-D board, a serial port was used. This board will echo all eight channels of its outputs in raw bits after it receives any ASCII character from the serial port.
HyperTerminal was used to read the channel bit values. Power was also applied to the board. The proper baud and communication settings were made and a carriage return was sent to the board. Indeed the eight channel's bit values were echoed back on the computer screen.
I then retook the garage door data. I just hit a carriage return after moving the garage door to a certain level and read channel one's bit value. I then recorded this bit value along with the distance the garage door was from the floor. A plot was then made of the bit value vs. the garage doors position above the floor (in inches).
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Data Set & Graph
Again you can see that a straight line was obtained.
Finalize all of your wiring and routing and mount your analog to digital converter and connect it permanently to your home automation computer. Insure all wires are routed properly so they do not interfere with any garage door operation. Connect the potentiometer output wires to the analog input channel. Plug the wall wart into its designated outlet.
Develop the Software Interface
Now that you are finished with the hardware interface it is time to work on the software. This software will convert the bits displayed on your analog to digital converter to inches (that the garage door bottom is above the floor).
Again please reference the Analog to Digital Converters guide as the following instructions are abridged below.
If you have any problems with the instructions below, please post your data obtained and I'll help you through the rest of this procedure.
The slope intercept formula of Y = mX + b will be used with Y being the bit value and X being the inches the garage door is from the floor value.
To solve for m (slope) and b (Y intercept) we need to select two data points from the graph above. I like to select two data points just inside the max and min values so the following points (X, Y Pairs) will be used (again these values are read directly off of the data graph/chart above).
10.5, 276
68, 856
Solve for m using the equation:
m = (Y2-Y1) / (X2-X1) or (856-276) / (68-10.5) or 580 / 57.5 or 10.087
The b intercept can be calculated using Y = mX + b and substitute the m value above with the first data point used (in this case 10.5, 276).
276 = 10.087 (10.5) + b
Solving for b yields b = 276-(10.087 * 10.5) or 161.865
So now our equation can be represented by:
Y = mX + b
Y = 10.087X + 161.865
Since Y represents BITS and X represents INCHES, we can rewrite this equation as follows:
BITS = 10.087 (INCHES) + 161.865
Since we will know the BITS from the Analog to Digital converter, we must solve the above equation for INCHES (the unknown variable). Rearranging the above equation yields:
INCHES = (BITS-161.865) / 10.087 or
INCHES = 0.099 * BITS-16.05
Test this calculation by using another X,Y pair from the graph above. Lets take the pair 57,752.
If we use the equation above to solve for INCHES knowing the BIT number we get
INCHES = 0.099 * 752-16.05 which yields 58.4 which is pretty close to 57 (the corresponding X value).
Lets further test this calculation using another X,Y pair from the data above. This time lets use pair 20.5, 375.
INCHES = 0.099 * BITS-16.05
INCHES = 0.099 * 375-16.05, which yields 21.08 which is pretty close to 20.5 (its corresponding X value).
Final Accuracy Test
Now that you can convert a bit number from the analog to digital converter to real world inches, test the final accuracy of your measurement system. Move the garage door to a position say 1/3 of the way open. Read the bit value from the analog to digital converter. Using the above equation INCHES = 0.099 * BITS-16.05, calculate the expected inches result. Then measure the actual distance the bottom of the garage door is from the floor and it should match this value very closely.
Continue this test for other open stages of the garage door (say 1/2. 2/3, and 3/4 open). Also check the fully closed and fully open positions. These results will let you know the relative accuracy you can expect for your system.
Please note that several factors will determine the accuracy and repeatability of your system, most importantly the total bits of your analog to digital converter. If you have an eight bit converter vs. a ten bit your resolution would be less and repeatable results would be more sporadic (though within a certain window range). Again, please refer to the guide Analog to Digital Converters for further details.
The PH Anderson Analog to Digital Converter
As mentioned earlier, I am using THIS PH Anderson eight channel 10-bit analog to digital converter. The unit is $40 plus $6 shipping. I also emailed Mr. Anderson and asked for a version so all of the eight channels of bit data is in one line, rather than the two separate lines as shown in its literature. This made the serial program to retrieve the specific bit channels of data a lot easier to write.
The main advantage this unit has over other analog to digital converters included in the Ocelots SECU16 and the Elk M1 Gold is its ten bit accuracy vs. just the eight bits included with those other two systems. Again, refer to the Analog to Digital Converters guide for additional details as to why this may or may not be important for your application. I also wanted the additional ten bit resolution channels for other projects as well. I would also like to add that I found corresponding with Mr. Anderson via email to be a very pleasant experience.
Integrating With Home Automation Software
I currently use HomeSeer ver 1.7.43 with MainLobby for my visual displays. In order to integrate the PH Anderson Analog to Digital Converter I had to create a couple of scripts. These scripts also incorporated the equation determined above which converted the bit number to inches that the bottom of the garage door was above the floor.
First, two scripts are required for the PH Anderson Analog to Digital Converter. One script sets up the serial port and polling, and the other actually acquires the data from the channels.
I currently have the PH Andersons board on serial port number ten, but had to use serial port number threes resources. This is partly because I have two on-board serial ports on my HomeSeers computer and also incorporate an Edgeport 8 serial expander. The serial ports start at Com1 and Com2 for the on-board motherboards ports, but then skip to Com5, Com6, Com7, Com8, Com9, Com10, Com11, and Com12 for the Edgeports serial ports. I simply could not get any programs working within HomeSeer using any OpenComPort or CloseComPort with that higher serial port number (so I therefore used Com Port 3 resources since Com3 and Com4 were not used in my system).
I created HomeSeer devices (device type interface variable) R1 through R8 which will represent the value of the eight channels of the PH Anderson Analog to Digital Converter.
To set this serial interface up I incorporated the following VB Script below. Note that two resources I found handy while writing this code were ASCII Lookup Tables and Microsoft's Visual Basic Scripting Guide.
Code:
sub main() 'Analog board connected to Com 10, but using Com3s "resources"!
hs.CloseComPort(3)
e=hs.OpenComPortex(10,"9600,n,8,1",1,"analogdatanew.txt","Fran", chr(10), 3)
if e<> "" then msgbox "Error opening COM10: " & e
hs.SendToComPort(3), chr(100) 'you can send "ANY" data to the comm port to get data back
hs.waitsecs 2
hs.CloseComPort(3)
end sub
This program opens the com port, calls the subroutine Fran in the analogdatanew.txt script (which it will pass the data to), then sends an ASCII character 100 (any ASCII character will do) to the A-D board so it will echo the data back via the serial port.
I then setup an event in HomeSeer which runs every 20 seconds that calls the above script (as shown below). The timing of the run cycle will depend on your specific application.
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HomeSeer Event Setup
The details of the analogdatanew.txt script are listed below:
Code:
sub Fran (data)
dim myArray
dim i
dim x
dim hc
i = 0
'data separated by spaces, but actual number of spaces between data points change depending on the "bit" value (0 to 1024)
myArray = Split(data," ", -1, 1)
for x = 0 to ubound(myArray) 'Get "data" into the array "myArray"
If myArray(x) <> "" Then
i = i + 1
Select Case i 'This selects Homeseer device house codes for data channels
Case 1
hc = "r1"
myArray(x) = 0.099 * myArray(x) - 16.05 'Calculation Converts Bits to Inches Garage Door is From the Floor
Case 2
hc = "r2"
Case 3
hc = "r3"
Case 4
hc = "r4"
Case 5
hc = "r5"
Case 6
hc = "r6"
Case 7
hc = "r7"
Case 8
hc = "r8"
myArray(x) = 0.486 * myArray(x) 'LM34 Temp Convert
End Select
hs.setdevicevalue (hc), myArray(x) 'write data to Homeseer device
hs.setdevicestring hc, myArray(x) Â 'write string to Homeseer device
end if
next
end sub
Note that HomeSeer device R1 will now contain the inches the garage door is from the floor. Also note that this value was written in the device value and string as well.
Also, for what it's worth, notice that I have an LM34 temperature probe installed on channel 8 of the PH Anderson Analog to Digital converter and show the necessary calculation to convert this reading to degrees F which is written to the HomeSeer device R8 (showing the versatility of this A-D board).
Well now we have a HomeSeer device which shows the value in inches, but wouldnt it be nice to know the percent the garage door is opened? In other words is the garage door half-way open, 80% open, etc. This may be more useful than knowing the actual inches.
This percentage number is easy to calculate. When my garage door is fully opened the bottom of the door is 83 inches from the floor. This represents being 100 percent opened. Of course when the garage door is closed its bottom is (approximately) zero inches from the floor. This represents zero percent opened. Now we need to express the actual inches measured as a percentage based on these two limits. To do this we need to divide the inch reading from the maximum 83 inch number, then multiply that result by 100. In other words the equation would be:
Percent Open = Inches / 83 * 100
I also created a HomeSeer interface variable device R9 which will represent this percent open number. The code is incorporated below (gdpercent is the variable that represents this percent open value).
Code:
sub Fran (data)
dim myArray
dim i
dim x
dim hc
dim gdpercent 'Percent that the garage door is opened
i = 0
'data separated by spaces, but actual number of spaces between data points change depending on the "bit" value (0 to 1024)
myArray = Split(data," ", -1, 1)
for x = 0 to ubound(myArray) 'Get "data" into the array "myArray"
If myArray(x) <> "" Then
i = i + 1
Select Case i 'This selects Homeseer device house codes for data channels
Case 1
hc = "r1"
myArray(x) = 0.099 * myArray(x) - 16.53 'Calculation
gdpercent = ((myArray(x)/83.0) * 100) 'Convert to percentage open
hs.setdevicevalue "r9", gdpercent 'write data to R9 Device
hs.setdevicestring "r9", gdpercent 'write string to R9 Device
Case 2
hc = "r2"
Case 3
hc = "r3"
Case 4
hc = "r4"
Case 5
hc = "r5"
Case 6
hc = "r6"
Case 7
hc = "r7"
Case 8
hc = "r8"
myArray(x) = 0.486 * myArray(x) 'LM34 Temp Convert to Deg F
End Select
hs.setdevicevalue (hc), myArray(x) 'write data to Homeseer device
hs.setdevicestring hc, myArray(x) 'write string to Homeseer device
'hs.writelog "Channel", hc
'hs.writelog "Data", myArray(x)
end if
next
end sub
Wow, we now have two HomeSeer devices which show garage door monitor information. One device (R1) shows the actual inches the bottom of the garage door is from the floor. The other device (R9) displays the percent open or the percentage the garage door is opened.
You can now use these values to trigger other events or code as you wish. For instance you may want to trigger an event which calls you after a certain amount of time after you open or close the garage door in case it doesnt open or close fully (garage door opener gets jammed).
Since I have MainLobby incorporated into my HomeSeer automation system, I wanted a cool display which represented exactly where the garage door was or in other words, graphically show its percent open condition. I could do this very easily by showing the percent open number as a variable for a slider, but this did not look much like a garage door.
Well, my MainLobby friend Fungun (aka Tim) came to my rescue by making a series of garage door jpg images (11 total) which showed a white, double car garage door in various stages of open. I renamed these images as garage1.jpg (fully opened), garage10.jpg (10% open), garage20.jpg (20% open), etc. all the way up to garage100.jpg (fully opened). Now all I have to do is pass the "garage door percent" HomeSeer device value as a variable to Main Lobby (range), then do a condition statement based on the value of this device and display the proper jpg on my Main Lobby scene.
The code which incorporates this feature is shown below.
Code:
sub Fran (data)
dim myArray
dim i
dim x
dim hc
dim gdpercent 'Percent that the garage door is opened
i = 0
'data separated by spaces, but actual number of spaces between data points change depending on the "bit" value (0 to 1024)
myArray = Split(data," ", -1, 1)
for x = 0 to ubound(myArray) 'Get "data" into the array "myArray"
If myArray(x) <> "" Then
i = i + 1
Select Case i 'This selects Homeseer device house codes for data channels
Case 1
hc = "r1"
myArray(x) = 0.099 * myArray(x) - 16.53 'Calculation
gdpercent = ((myArray(x)/83.0) * 100) 'Convert to percentage open
hs.setdevicevalue "r9", gdpercent 'write data to R9 Device
hs.setdevicestring "r9", gdpercent 'write string to R9 Device
'Determine Garage Door jpg to display based on percent garage door is opened
If gdpercent < 3 then
hs.plugin("MLHSPLugin").MLServeCMD "MLServeCMD.SetVariable|range~c:\Program Files\Cinemar\images\garage1.jpg"
elseif gdpercent >= 2 and gdpercent < 10 then
hs.plugin("MLHSPLugin").MLServeCMD "MLServeCMD.SetVariable|range~c:\Program Files\Cinemar\images\garage10.jpg"
elseif gdpercent >= 10 and gdpercent < 20 then
hs.plugin("MLHSPLugin").MLServeCMD "MLServeCMD.SetVariable|range~c:\Program Files\Cinemar\images\garage20.jpg"
elseif gdpercent >= 20 and gdpercent < 30 then
hs.plugin("MLHSPLugin").MLServeCMD "MLServeCMD.SetVariable|range~c:\Program Files\Cinemar\images\garage30.jpg"
elseif gdpercent >= 30 and gdpercent < 40 then
hs.plugin("MLHSPLugin").MLServeCMD "MLServeCMD.SetVariable|range~c:\Program Files\Cinemar\images\garage40.jpg"
elseif gdpercent >= 40 and gdpercent < 50 then
hs.plugin("MLHSPLugin").MLServeCMD "MLServeCMD.SetVariable|range~c:\Program Files\Cinemar\images\garage50.jpg"
elseif gdpercent >= 50 and gdpercent < 60 then
hs.plugin("MLHSPLugin").MLServeCMD "MLServeCMD.SetVariable|range~c:\Program Files\Cinemar\images\garage60.jpg"
elseif gdpercent >= 60 and gdpercent < 70 then
hs.plugin("MLHSPLugin").MLServeCMD "MLServeCMD.SetVariable|range~c:\Program Files\Cinemar\images\garage70.jpg"
elseif gdpercent >= 70 and gdpercent < 80 then
hs.plugin("MLHSPLugin").MLServeCMD "MLServeCMD.SetVariable|range~c:\Program Files\Cinemar\images\garage80.jpg"
elseif gdpercent >= 80 and gdpercent < 90 then
hs.plugin("MLHSPLugin").MLServeCMD "MLServeCMD.SetVariable|range~c:\Program Files\Cinemar\images\garage90.jpg"
elseif gdpercent >= 90 then
hs.plugin("MLHSPLugin").MLServeCMD "MLServeCMD.SetVariable|range~c:\Program Files\Cinemar\images\garage100.jpg"
end if
Case 2
hc = "r2"
Case 3
hc = "r3"
Case 4
hc = "r4"
Case 5
hc = "r5"
Case 6
hc = "r6"
Case 7
hc = "r7"
Case 8
hc = "r8"
myArray(x) = 0.486 * myArray(x) 'LM34 Temp Convert to Deg F
End Select
hs.setdevicevalue (hc), myArray(x) 'write data to Homeseer device
hs.setdevicestring hc, myArray(x) 'write string to Homeseer device
'hs.writelog "Channel", hc
'hs.writelog "Data", myArray(x)
end if
next
end sub
I copied all of the garage jpg images into my cinemar/images directory. I then created a library button on my MainLobby scene and pointed its label to this range variable.
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MainLobby Button Dialog Settings
The results of this MainLobby display are shown below. I would like to again thank Fungun for creating these images for me.
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Scene With Garage Door 20% Open
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Scene With Garage Door 50% Open
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Scene With Garage Door 80% Open
Conclusion
That concludes this How-To on building the ultimate garage door monitor. Remember, any amateur home automation enthusiast can tell you if the garage door is open or closed based on magnetic contact sensors, but a REAL HA person can tell you within a few inches the EXACT position of the garage door itself!!
Why do you need to know this information, well, because you now CAN!!
My setup has been working for months and it is nice to know the position of the door, especially in the summer months when we crack this door to let some air in. Also, many people have expressed this interest because they occasionally have their garage door openers jam, and come home to an open door at the end of their work day!
As always please feel free to provide comments and suggestions below!