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/diy/ - Do-It-Yourself


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>> No.1610717 [View]
File: 20 KB, 633x755, traffic signals.png [View same] [iqdb] [saucenao] [google] [report]

I'm trying to come up with some circuit ideas using the 4017 counter IC. Made this simulated toy circuit for controlling a traffic signal. The idea is to use this circuit with a microcontroller to control many (or all) traffic signals of an intersection.

It works by first setting the "Enable" input high, followed by a "Reset" pulse and then clocking required number of "Data" pulses into the 4017 counter IC. The aspect is changed after setting the "Enable" input low. The outputs 1..4 of the 4017 select a different light combination.
- 1 clock pulse: red,
- 2 pulses: red+amber,
- 3 pulses: green,
- 4 pulses: amber.

There's also a fail-safe watchdog function. If the "Enable" signal hasn't changed after a certain time period, the 4017 counter is reset to "0". This starts flashing the amber light, indicating that the traffic signals are not functional.
The current version is kind of crappy as the lights can't change simultaneously. Would need to have some kind of "strobe" signal.

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