The solution above just delivers a solution for power control via PWM. I use a similar setup which forks fine.
But I still seek a solution on how to measure the resistance of the nice coil. Currently I heat it up and I want to check the resistance to avoid burning the coil away.
Any ideas on this, I tried to use an opamp as an differential amplifier in the PWM pause but up to now I didn't succeed in getting somehow useful Output for the Arduino ADC.