Infrared UART

Wireless Infrared UART prototype can be built by using two PIC16F876A controllers. One as IR receiver with dedicated Infrared decoder like SFH505A, SFH506 or similar IR receiver IC and other microcontroller as a transmitter via IR LEDs. This is relatively simple design and doesn’t require advance electronics knowledge or programming skills, especially if you are going to use attached schematic and code. Wireless communication achieved by PIC USART module sending 8 bit of serial data to TX pin driving Infrared LED on the Transmitter side and SFH505A IR Detector that decodes received data and drives receiver PIC RX pin.2 PICs USART units should use the same clock frequency settings. See design schematic for more details.

Wireless UART Receiver Prototype Board
Wireless UART Transmitter Prototype Board

Assembly files with transmitter/reciever control code available at the bottom of the page.Tested range was about 2 meters, use LED reflector or high power IR LED to increase the effective distance.To verify circuit operation point the transmitter in the direction of receiver unit like a remote control, press any keypad key and you should see its binary code shown on LED bar graph connected to PORTC.Currently only one way communication is implemented, in order to make it bidirectional a second receiver with different carrier frequency is required. Further improvement can include upgrading both receiver and transmitter codes to use interrupt routines instead of pooling technique thus making it more efficient.
Wireless UART Schematic

Assembly code is here ,see a short video demonstrating circuit operation.

Posted in PIC16F87X Projects
 

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