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IR REMOTE-CONTROLLED VIDEO MULTIPLEXER

by Peter Gibbs

Start ý The Objectives ý Circuit Operation ý Decoding the URIC ý Short Program ý The Multiplexer Design ý Software ý Sources and PDF

SHORT PROGRAM

Listing 1 (IRTEST.BAS) shows a short Stamp program that allows you to visually examine the digital code produced by the UIRC buttons. A storage scope may also be used. Hook up the Sharp module to the Stamp (bit 7) and download Listing 1 from the PC to the Stamp.

Note that although the high pulse preceding each low pulse is read, the value and the leader pulse width are not stored. For the UIRC used, logic 1 returned a count between 135 and 145, and logic 0 fell between 70 and 80. You can try this method with other remotes and look for unique patterns.

Table 1 shows the binary data patterns (first 12 bits only), obtained for the buttons on my UIRC, in TV mode. I converted the count values to binary using integer division by 110, a number midway between the two ranges.

Table 1ýHere you can see the binary bit-string patterns for the 3-in-1 Radio Shack UIRC.

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