You can also use an external powered USB hub, this is what i usually use for experiments. Double check your wiring, keep in mind that with an external supply you can eventually damage your USB connection port. Use and external power supply if you pc can not supply enough current to run all your devices. Will that affect readings too much? Connect the sensor as the circuit you find above. Should I connect a ohm resistor in series with the coil to limit current. The current drawn by the sensor is about mA. Unfortunately my multimeter detects the connection between H1 and H2 to be short circuit shows a resistance of 30 Ohm which is very lowhence when i connect this to my arduino voltage across USB drops to 3.
Then you could apply the math of my library to convert Rs to ppm, and to estimate the Ro of the sensor.īy the way, you dont happen to have any video with the testing of this project? Blowing on it and showing some values from the UART? As I can't test this myself right now, it would be awesome to see it working on video. Once you have prove that your sensor works, read the sensor resistance using your ATmega and the pull-down sensoryou should get the same resistance as the multimeter. Blow on the sensor and this resistance should decrease. Then use a multimeter to read the resistance between A and B.
Apply 5V voltage at least from a mA source to the H pins of the sensor. I need to get ppm i should know how to find Ro. The datasheet states that Rs should be between 30Kohm and Kohm. Said that you know how many ppm there are, you can measure Rs of the sensor, and then you can get Ro. Please can you explain step by step how to calculate the value of Ro? Hello, take a look at "Ashutosh Bhatt" comments, May 28, and June 1, and my reply. The chance for getting this to work is possibly quite high then? Hello Davide, i am not able to follow your calculation.
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