Circuit for Transmitter

Figure above is receiver circuit. The power supply is connected to the 5v regulator to jot down the voltage from 9v to 5v because the PIC can only receive 5v of supply if not, the microcontroller will be damage. The supply also connect to the 3.3v regulator to jot down the 9v supply to 3.3v supply and connect it to the XBee chip. The XBee can only accept 3.3v of supply and if it not, the Xbee chip will be burn or damage. But, if you using the XBee module, you no need to connect it to the 3.3v regulator, you can just directly connect the supply 5v at the PIC because the module it self already have the built-in circuit to jot down the supply.

As for the crystal, I'm using the 20MHz because it is the maximum speed that PIC can reach to read the program in one clock pulse. This crystal has no polarity and it always connect to the 13 and 14 pin of PIC because that pin have clock peripheral. And the two capacitor at each side of the crystal is to filter the noise.

The two variable resistor is to control the dimmer of the light and the speed of the fan and it is connected to the analog I/O port because analog data can receive the voltage between 0v to 5v range. So, the variable resistor is suitable to connect to the analog I/O port because to dim and bright the light and slow and fast the fan. If the voltage is lesser then 5v, the light will be more dim and it depends on the voltage that been receive from variable resistor to the PIC and the PIC will transmit the data to the receiver circuit. Same goes to the variable resistor that control the speed of the fan.

As for the push button, it is simply connect to the digital I/O port because it just function to ON and OFF the radio. The digital I/O port can only receive the 5v and 0v so it is suitable for the push button. And it can connect to which ever pin but make sure that the pin is digital I/O port.

The XBee module need to be connect to the receiver and transmitter port. Because the PIC will transmit and receive the data from that port. It is easy to use XBee because you can directly connect it to the PIC as simple as the circuit above. But, to connect the XBee module to PIC, the pin of receiver at the PIC must be connected to the transmitter of the XBee module and vise versa.

And finally, the all the LED inside this circuit is as the indicator when I construct this circuit. It is because to make sure that the circuit can be function and receive the data.