Electronic turn signals

Neil

Supporter
Some time ago I was wiring a car and I wondered why I did not find an electronic solution to turn signals and flashers. Some digital logic, an astable timer, two relays, and a handful of small components can do the job. Any good technician can lay out this circuit on a small printed circuit board. It can vary the flasher frequency by changing the value of one capacitor and the turn signal indicators can be incandescent lamps or LEDs. If the P-channel MOSFET is sized appropriately, it can drive even heavy loads if necessary. I've attached two PDF files to show the circuit and how it works.

"Turn Signals Diagram" is the overall circuit. "Turn Signals 2" is a modification that allows the circuit to be simulated on a computer. The resulting waveforms are shown on the second page.

I could add an "Emergency Mode" flasher if anyone is interested.

If anyone has questions, let me know. Feel free to copy & build it as you wish.
 

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Steven Lobel

Supporter
Looks really cool. Would love to see Hazards in there and then a You-tube video and parts list with lots of pics for those of us who are not electronically inclined.
 

Neil

Supporter
Actually, adding a "Hazard Mode" was easy- just use a DPST switch to short each of the momentary pushbuttons for Right and Left turn signals. The lamps will all flash until the switch is turned off.
 
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