Recent content by rdheiliger

Read the "Solar Sensor2" post. There is an excel and word download there with tests I did using a solar meter I own showing volts from the DS2438. If you have trouble with the download drop me your email and I will send either the excel spreadsheet or word document. RD

A Microsoft Word document containing the spreadsheet in the previous Post. RD

I have discovered that a quarz Halogen lamp can be used to calibrate the Hobby Boards Solar Sensor. The attached spreadsheet (excel) has the data I recorded and a description of how the calculations are done. If you would like a copy of the data and chart in Microsoft Word format, give me your...

I don't understand what you mean by one or two, as to the sensor mount. RD

Measure the +5vdc on the sensor. I have found that the supply voltage can drop with little load. I use 18B20 with an external +5 supply, power injector and they work fine. When using an external supply, disconect the +5 from the 9490, but leave the common connected. Recheck and make sure you...

On a sunny day put the sensor in the sun. record the voltage, wait till a cloudy day and record the voltage. Use a voltage just below that of the sunny day for that symbol vice versa. Hope that is simple enough ;) RD

I forgot one thing in the last post. Dividing the voltage in the current A/D register by 4096. The resolution of the current A/D converter is .2441 mV. The resolution of the voltage A/D converter is 10 mV. The statement that one would only be able to see night and day would be wrong when the...

I forgot one thing in the last post. Dividing the voltage in the current A/D register by 4096. The resolution of the current A/D converter is .2441 mV. The resolution of the voltage A/D converter is 10 mV. The statement that one would only be able to see night and day would be wrong when the...

Finaly got to doing the experiment. Did not use the 1 wire solar sensor. Put the CLD240E in series with both the 390 ohm and 4.7K ohm resistors accross a 5vdc supply. Measured the voltage drop accross the sense resistor with a digital multimeter. And, recorded the multimeter volts and my SP1065...

The 4.7K resistor is just an experiment I did on a bread boad. To get some idea as to what the characterisitics of the CLD240 are. The data sheet for it does not have a graph of the current/solar flux relation. Most other photodiods and photo xistors have a graph of that relationship, and it is...

The Hobby boards solar detector uses a CLD240E photodiode in series with a 390 ohm sense resistor. The sense resistor is accros the current input A/D of a DS2438. The DS2438 records the voltage drop accross the sense resistor. The current thru photo diodes is proportional to the solar flux. So...

I set up an experiment. I origionly intended to connect the CLD240E to the analog voltage input of the DS2438, not the current inputs, and played with just the sensor and a resistor size untill I got a result in the 0-5V range. Found that a 4.7K resistor produced about 4volts with the sensor in...

After reading the data sheet for the DS2438 a bit closer. The number returned from the DS2438 is the voltage drop across the sense resitor, and you have to calculate the current with ohms law E = IR. The formula they give is : Current = current register base 10 / (4096 * sense resitor ohms)...

My last post can not be correct. Using the max current in the other posts, .250A, would calculate out to only a fraction of a watt/sqM. I know that in full noon sun, at summer solstice there is about 1000 W/sqM. Will just have to wait and compare the numbers to my meter. From reading the specs...

Good to know that it is the CLD240E. This is a formula for getting Watts/square meter, from the current reading obtained on the Solar detector board. Assuming that the current reading from the DS2438 on the solar detector is in Amps: Solar detector Amps/13ua/sqcm = milliwatts/square...