Sensor List

Its datasheet does not show what kind of output it having. However, most ph sensors output voltage.  You may need Ross' terminal board with amp to read fine ph value change.  If you played with Ph sensor before, you probably know all PH sensor requires periodically calibration with pure water, if you want to have very accurate reading. If just measuring the PH value in soil, then you don't need to do calibration often.
 
CAI_Support said:
Its datasheet does not show what kind of output it having. However, most ph sensors output voltage.  You may need Ross' terminal board with amp to read fine ph value change.  If you played with Ph sensor before, you probably know all PH sensor requires periodically calibration with pure water, if you want to have very accurate reading. If just measuring the PH value in soil, then you don't need to do calibration often.
Click to expand...
 
Been a long time since I interfaced to pH sensors, but last time I did they needed particularly high input impeadance amplifiers (>10M)
My amplifiers have been constructed (intentionally) to have medium impeadance inputs to assist with noise.
They may work, but I don't think they'd be a "good fit" unless there is a buffer amplifier after the pH sensor (unless things have changed)
 
CAI_Support said:
TP-Link model TL-WR702N wireless N wifi repeater/bridge/ap/router can be set as pure wifi bridge mode in browser, Then once you configured WebControl with network cable, simply plug into this little wifi box, WebControl will run on your network over wifi.  It will show on the network the IP address you configured for the WebControl and MAC address.  Right now, it is selling for $20 on Amazon.
 
WC32 is 10/100 full duplex.  WC8 is only 10BasedT half duplex.
Click to expand...
 
hope this one works
 

Model Number:

WI-wr155N2

Brand Name:

Wiwicom
http://www.aliexpress.com/snapshot/6019947621.html
 
I think that PH sensor just two piece of metal, when two kind of metal put into same solution, it will produce some voltage differences between them.  Depends on the metal being used, the voltage can be different in scale.
More advanced PH sensors have two actual sensors in one, one for reference, the other is for measurement, measuring input should be around 400M impedance.  The output in most cases are 59mV/PH
 
CAI_Support said:
I think that PH sensor just two piece of metal, when two kind of metal put into same solution, it will produce some voltage differences between them.  Depends on the metal being used, the voltage can be different in scale.
More advanced PH sensors have two actual sensors in one, one for reference, the other is for measurement, measuring input should be around 400M impedance.  The output in most cases are 59mV/PH
Click to expand...
 
Conventional pH probes don't use metal probes. Typically a pH7 solution of potassium chloride specifically to avoid the direct metal-to-solution layer.
 
There are now solid-state pH sensors that eliminate many of the historical problems with pH probes, but I'm not specifically familiar with interfacing to them.
 
Efried,  You had asked about DHT22 sensor before for humidity and temperature.  Now, with I2C support, you can actually use AM2321, which from we read on web is same as DHT22 but with I2C interface.  However, due to this sensor only has one address, you can only use one such sensor on the I2C bus. (you can have different sensors on that same I2C bus, but only one AM2321).
 
Ross has successfully worked on his I2C pressure sensor measurement project on WC8 with latest firmware.  You may consult him for details.
 
Since there are arduino bricks out there offering 5 V signals, I will give this a try...
Tschmidt said:
1) I thought about adding a CO detector to my wood heat controller but decided not to. Detector needs to be calibrated and has relatively short life time compared to rest of the system.  If you want fire and smoke integration I'd recommend getting an off the shelf unit that supports  interconnection and do some experiments to determine how the interconnect signaling works. Once you figure that out build a circuit to optically isolate the smoke alarm from WC.
Click to expand...
 
What Tom said was that gas sensor like MQ-2 can be purchased cheaply and hookup easily.  However, to use gas sensor, you will need to calibrate it at 20C and 33% and 65% humidity.  Without calibration, it will read back value, but that value does not mean much.  It is not arduino will automatically calibrate it, calibration is a separate process.  Using WC can read back value easily, too.
 
For example, look this LPG sensor,

http://www.ebay.com/itm/131292766089

it has a calibration trimmer.  You will need to calibrate its reading against an accurate known gas meter to figure out what the reading actually means.
 
this one is CO sensor,
 

http://www.ebay.com/itm/141447763251

 
although it can not be used as a meter to measure the CO gas ppm without calibration,  it can be used to alert you when CO level is higher than normal.  For that, it may be worth it.  A lot of places using natural gas to heat in the winter.  Leaking of CO is dangerous, but hard to detect by human.
 
Simply wire its analog output to WC's analog input, power the sensor with 5V, one can see the CO level reading.  In its first 24 hours, the little heater inside sensor burning off manufacture residues, after that period of time, one can set the PLC to send email alert when CO level is higher than normal.  It may send false alarm when temperature and humidity changing, but fine tune it over the time it can get rid of false alarm.
 
yeah I should use his board but, i would like to know why i got this up and down value. 
 
 
this sensor is based on lm393 chip.
 
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