One example is the Model 1522 temperature sensor sold by SmartHome. The LM34 can be connected to an A2D board with no other parts if desired. Its cost, availability, and ease of connection make it ideal for our purposes. The rest of this article will focus on connecting the LM34 to an A2D board, and generating useful output from it. The LM3x sensors produce 10 milli-volts of electricity per degree of temperature.
Connections are as shown in the diagram at right.
The three wire interface used to operate the LM34 can be run more than a hundred feet without significant signal degradation. It is a good idea to add a 0.1 uF capacitor connected at the A2D board input. This helps improve the stability of the measurement by reducing the effects of noise picked up on the Signal line. Connections to your A2D board are very straight forward. Vout or Signal is the output from the temperature sensor and represents the temperature at 10 mV per degree.