Hi all. I’m working with an automotive Hall effect crankshaft position sensor and looking to invert the output signal. I understand this is outputting square wave, but I’m very new to this process and am looking for suggestions and guidance. I was looking at using a 74hc14 to accomplish this. When testing the sensor for GM pcm I notice reading signal from a clockwise rotation, the output reads 0v and comes up as the tooth crosses goes up to 5v and holds until the next tooth enters and it drops back to 0v front of tooth and 5v again as tooth exits. The ford pcm operates opposite of this.
What if you use an NPN transistor?
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I was wondering if this might be an option. I have also tried a PC818 1 channel optocoupler, but no luck. Was wondering if the transistor would output 5v at 0v input and 0v out at 5v input.
No junction transistor will give you 0V out in saturation.
However a suitable logic level compatible MOSFET would.
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Hi, @timu33
Welcome to the forum.
Can you please post a diagram of how you use the opto-coupler with the sensor?
Thanks.. Tom.. 
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Why do you need to invert it ? If it it is going into an Arduino of some sort ( this is Arduino forum!) you can invert it there , but I’m surprised this is needed , if so Carnot you just use a correct Ford sensor
Your sensor may output a low voltage ( ~0.5v?) depending on its type and you need to check that .
I have one for an unknown vehicle and it detects the edges of teeth so you get a going high “ spike “ followed by a negative spike - each about 0.5volt. I’m using an op amp to amplify and condition it .
Hall type are not so common on cars , so you need to be sure what you have .
- you need to check that .
- Are you trying to make an ignition controller? Google will find lots of examples .
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That will do it
Doesn't your GM sensor require a pull-up resistor?
Reason is I’m using the GM sensor to control both PCMs. I will definitely double check on if the GM sensor is using a pull up/pull down resistor.
I thought the GM sensor was open collector output so it needs an external pull-up.
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I guess for my application the 58x gray sensor has an internal pull up resistor. So to invert this so that the ford pcm sees opposite signal, could I use a pull down sensor between the gm sensor output signal and the ford pcm pins? I currently have a breakout harness that has a signal pin coming out of the GM sensor. I’m trying to feed this into the ford connector so that the ford pcm reads crank signal off the GM sensor. Both cars used a 60-2 reluctor wheel. Both pcms use 0-5v signals, but seems like the GM pulls up and the Ford sensor pulls down.
Gm side
A.5v
B.Signal
C.Ground
Ford
A.5v
B.Ground
C.Signal
This is all you need to do the inversion
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If I have logic backwards and gm is pull down and ford is pull up, could I still use this diagram and just move the resistor to the ground side?
It doesn't matter the circuit will still invert the GM signal. When GM is 0 Ford is 5 when GM is 5 Ford is 0 OR when GM is 5 Ford is 0 and when GM is 0 Ford is 5
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Hi,
I think this may help;
One circuit to do it all.
Tom..
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