So I need some help with converting this schematic to 3.3v logic. In this forum they took the crank position sensor and was able to read it with arduino uno. I have tried this and it works great but I needed some more storage and speed and I got myself a Arduino Due. From what I am told 5v will fry this board so I need to convert that schematic to 3.3v but I am not sure how to go about this. Hopefully someone can advise me. Thanks in advance.
I believe you are looking for a level shifter:
You don't state what the incoming voltage happens to be.
This article is also worth looking at:
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What I understand is the sensor in that schematic is a variable reluctance which ouputs an ac sin wave voltage dependent on the speed and the circuitry clamps it into 0v to 5v range. I just need it clamped into 0v and 3.3v. if you think just putting to resistors as they show will do that I will give it a shot was just worried if it would distort the signal or not
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the best choice would be using an opto to to switch a 3.3v power source(same as board) in synchronicity with the 5v sensor signal.
This also guarantees there is no set of circumstances that gets more than 3.3 volts to your board.
but there are many ways to do a level shift, read up on them & select the one thats best for you.
You have the Arduino input labelled "interrupt". Is this a digital or an analog input?
In general, the resistive divider will not distort the signal, digital or analog as the Arduino input is very high impedance - if digital at least.
I am puzzled by the 1k resistor in the ground connection. 
i was just starring at that myself!
Sounds good I have it into one of digital interrupts as all this is for is counting how many times the shaft goes around in a set time. I have no idea what the 1k resistor is doing but it works so I ran with it. Thanks again
Yes, the resistor divider should work fine.
Like PaulB, I too am puzzled by the 1k to ground.
Do please let us know how it pans out
Sounds good 
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As we dont know what the ecu connections are we cant assume the black wire is a ground.
With my connections the ecu is the arduino so the leads that say they go to the ecu are no there.
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