31-01-2012, 03:08 PM
IR SWITCH AND REMOTE CONTROL
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CIRCUIT DIAGRAM :
IR DETECTOR CIRCUIT :
1. The detector circuit uses an IR detector TSOP 1738 commonly available in the market. This is tuned to detect IR pulses at 38Khz frequency and also it tuned not to respond to stray IR coming from natural light or any other source like tube light etc in your home.
2. Since IR detector can produce a sequence of signals when it detects IR radiation we are using a buffer which will, sort of accumulate signal received for about 1-1.5 sec and generate on signal. We are using CD4049 to do the buffering. The signal is send to the next stage
3. In this stage a 555 is used mono stable signal generator ,to generate a signal and prevent any further signal for a short period of 1 sec.
4. In this block we are using a flip-flop 74LS74 to toggle the switch every time we get a signal from the previous stage.