I'm exploring the differenet ways to make a tachometer for a small one cylinder 4 cycle motor. I have induced voltage from the spark plug wire and a hall sensor working. My next project is to trigger off of the primary side of the coil.
I built a full wave rectifier circuit (4 diodes). I hooked up a 5v led with resistor and got a blinking light. I expected the blink to coincide with the magnets on the flywheel moving past the coil. I next ran dc current from the rectifier circuit into a digital pin on an Arduino and immediately smoked the chip.
On a scope , with my limited ability to read it, I'm seeing a very high spike in the 200 volt range for 2-5 milliseconds. I need to bring this down to 5 volts so I can count the Hz.
Ideas?
Thanks!
I built a full wave rectifier circuit (4 diodes). I hooked up a 5v led with resistor and got a blinking light. I expected the blink to coincide with the magnets on the flywheel moving past the coil. I next ran dc current from the rectifier circuit into a digital pin on an Arduino and immediately smoked the chip.
On a scope , with my limited ability to read it, I'm seeing a very high spike in the 200 volt range for 2-5 milliseconds. I need to bring this down to 5 volts so I can count the Hz.
Ideas?
Thanks!
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