The temperature sensor is based on the TMP36 Low Voltage Temperature Sensors.
My first attempt at creating a wireless temperature sensor was using a TMP36 device from Analog. The TMP36 looks like a transistor because it is in a TO-92 package.
I soldered together an XBee Adapter board from Adafruit then I soldered the TMP36 directly to the adapter board. Using the layout above. I soldered the voltage input pin to the closest VCC trace, the ground to ground (obviouisly) and the Analog Voltage output pin to the AD0 pin.
This seems to work fairly well if you only have one input. If you plan to use multiple sensors on the XBee ADC inputs, you’ll need to set up a rail to rail op amp buffer. But that’s for another post.
Here’s a live sample of a TMP36 data stream from my back porch as derived from a chart on Pachube.com:
Large spikes are a known problem with the data collection downstream of the TMP36 and the XBee module. To be fixed soon, I hope.
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