Thank you for your reply!
I have looked into op-amps and I can get an understanding of how they work.
I have also now created a pwm of the signal to supply an op amp with.
My question is that can the arduino vary the voltage during a PWM?
In my attached image from the first post I want to create the higher voltage spike at beginning/end of crankshaft revolution.
Can I run the PWM at 4.5 volts then one at 5 volts to create the spike?
Many thanks!
Max