You will need the proper conditioning circuit to feed the rev signal to the lm2917.
You should cuple it using a cap a maybe a zener to keep the input voltage below max for the chip.
You may or may not need the diode on the ground pin.
I looked quick and did not see any circuits that would work with the ignition circuit on your bike.
He is making a "shift light" that lights at a certain engine RPM when the gears should be shifted to avoid over-revving the engine.
The datasheet for the LM2907/LM2917 shows a "normal" engine application but the inputs are a magnetic variable reluctance pickup or breaker ignition points for car engines.
Thank you guys for interesting!! My test bike, have a 1 cyl, and 2 stroke engine. I want to LED lights at the desired speeds (rpm), usually between 6000-8000rpm.
I have a speedo sensor with 3 wires on my bike (positive, negative, and signal). Today I measured between signal and negative wire a output frequency:
10km/h = 20Hz
15km/h = 30Hz
20km/h = 40Hz
50km/h = 100Hz
I dont know which type is sensor (can you identify with this parameters?), but when signal going out, a voltage is 4.25V, then drop on 0V (resistance is 43.8ohm), and again going to 4.25V, like a pulses or logical 0 and 1 ?
I'm thinking we can pick the signal off the ignition pickup sensor (low voltage ac) but the numbers you've
listed are not what I expected. I thought the sensor would reflect 1 RPM = 0.0166667 Hz. So 2000 RPM=33.3333 Hz but its not matching the values you've listed..?
I'm thinking we can pick the signal off the ignition pickup sensor (low voltage ac) but the numbers you've
listed are not what I expected. I thought the sensor would reflect 1 RPM = 0.0166667 Hz. So 2000 RPM=33.3333 Hz but its not matching the values you've listed..?
Ok here's something you can try...but I'm not certain about the measurements you've shown.
The frequencies seem high and aren't very linear.
But anyway...if you can pick the signal off the "Red" wire (0-3VAC), this might work.