Measuring temperature is a popular way to get started with analog sensing. This example uses the TMP36 low-voltage linear temperature sensor that is included in the XBee Zigbee Cloud Kit. The TMP36 is very easy to set up. It doesn't require any complicated circuits or tricky calculations to determine if it's hot or not.
The sensor generates a voltage output output that is directly proportional to the Celsius temperature. The hotter it is, the higher the voltage that is passed to the XBee's analog-to-digital converter (ADC). This reading is then sent via Digi Remote Manager to the XBee Zigbee Cloud Kit's online dashboard application where you can monitor the temperature right in your web browser.
To hook up a temperature sensor you'll need:
You'll configure the radio using your free Device Cloud account. (Note that radios can also be configured using XCTU.)
You will build this sensor circuit using the XBee Development Board. It's a good idea to unplug the USB power before working with the electronics.
You will use the XBee Wi-Fi Cloud Kit's web application to configure a widget for viewing the temperature readings from your sensor.
Now you can see the temperature using the analog input of your XBee Zigbee! Try getting data from various locations, like outside on your patio or inside your freezer. You can also add a graph widget to examine data over time. Log the changes in your office to see temperature shifting from day to night. Finally you'll have the documentation to convince your boss to buy you a blanket!
Remember that this temperature sensor is designed to produce stable readings, so it may take a few minutes for the sensor to fully reflect changes from its environment. If you want to experiment with rapidly changing sensor data try building the light sensor.