4) Wire up the Circuit
You will build this sensor circuit using the XBee Development Board.
- Plug in the three 10K ohm resistors to separate rows of the breadboard as shown. They will form a chain with the each resistor connecting to one end of each resistor on either side. These scale the input down from 3.3 volt input to near the 2.5 volt maximum of the XBee Zigbee’s ADC.
- Connect a red jumper wire from the open end of the first resistor to 3.3 volts power.
- Connect one end of a yellow (or any other color) jumper wire to the open end of the third resistor. Connect the other end of this wire to to the XBee’s AD1 pin.
- Plug in the photocell so that one leg connects to the same junction row as the yellow wire and third resistor. The other leg can go into an unused row. (A photoresistor doesn’t have any polarity, its orientation doesn’t matter.)
- Set the DIP switch for AD1 on the PCB to OFF to disconnect the soldered-on component.
- Here’s what everything should look like: