IR_REMOTE_CONTROL_RECEIVER_1

Published:2009/7/14 11:11:00 Author:May | From:SeekIC

The figure shows a schematic of the IR receiver circuit. The heart of the circuit is MOD1, an infrared detector module that removes the IR carrier frequency and transmits only the data that are encoded in the received IR signal. A suitable IR module is available at Radio Shack (No. 276-137).The IR module needs a clean 5-V power supply, which is provided by IC1, a 7805 regulator. Power is supplied to the regulator by 9-V battery B1. The output of the module is wired to a male DB-25 multipin connector. The infrared detector module receives a signal, filters it, and removes the 40-kHz carrier. The output of the module is a TTL-level signal consisting of long and short pulses. The PC records those voltage levels over time, while the signal is being sent, and stores the data in a file. The line normally used by the PC's printer port to indicate that the printer is out of paper (pin 12) is used in this project to accept data from the IR module. The I/O port is located at the address ox379. Bit 5 corresponds to input pin 12. Various software programs are required to let a PC store information input to its printer port. (All of the software is available on the Gernsback BBS-516-293-2283, v.32, v.42bis-contained in a file called IR-TEST.ZIP.) The source code of the first program, IRLOG.EXE, is written in C. The program stores the value it reads from the PC's printer port into an array. When the input line is logic high, the ASCII character 1 is stored in the array. When the input line is logic low, ASCII character 0 is stored.



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