This IR remote control that you can use to control other devices or circuits up to 8 devices.
The control codes are sent in RC5 format modulated to about 38 kHz carrier frequecy.The IR transmitter powered by the CR2016
which is a 3V button Cells Battery CR2016.To extend the life of the
battery this is done by putting the CPU into SLEEP mode for most of the
time and wake-up only when a key is pressed.
PIC16F630 is the heart of the transmitter used to send
IR command to receiver.It also generate 38KHz carrier frequency.The
CR2016 is 3V battery which is supply for the circuit.
When any key not pressed the CPU work in SLEEP mode to reduce baterry
power consumption and wake-up only when any key pressed. To wake-up the
CPU from SLEEP mode the CPU use interrupt on change feature which
interrupted when the state on PORTA change then the program execution
after an interrupt is at the interrupt vector, if the global interrupt
is not enabled, the program starts executing the first line of code
right after the SLEEP instruction.In the interrupt service routine the
software will scan the key that pressed and send IR command appropriate
with key pressed.
Fig 1. IR transmitter circuit
The receiver also use PIC16F630 to control all function then.When power
is applied to circuit the CPU will polling the IR input signal which is
the output from IR decoder module(TSOP4838).After
IR received the CPU decoding the IR command and turn on the buzzer
about 60mS to generate beep sound. If you want to know how to decode
the RC5 format read from this website.
The output (relay) work as a toggle output thus when the right IR
command decode complete the output will turn on and if the same IR
command sent again the output will turn off.
Fig 2. IR receiver circuit
Download Firmware(Hex) V1.0
Hex file to program into CPU both for
TX and RX.
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