Light Aircraft Association

I would like to change my Walter Mikron III tacho from mechanical to electronic, mainly due to routing difficulties. I have bought a suitable indicator, (sadly of Chinese origin!) but there is no clear suggestion of how or where to connect the black signal wire. The diagram shows a picture of a sensor, however the vendor does not sell them. I assume this is a phonic or Hall sensor but where can I get one to fit a Mikron? The diagram also shows (as an alternative?) the signal wire going to an alternator. Would that be the unrectified and unregulated output?
Can anyone with experience, enlighten me please?
Thanks, Dave

Could that alternator actually be a magneto? It is possible to pick off the impulses by connecting through a resistor (10k ish I think) to the ignition switch. I have the diagram for the set up in an RV if that helps. Not much different to the one in a Jodel before.

John

Hi John, The diagram shows a small icon picture of an alternator, with no mention of a magneto, however, if it works that would be brilliant as the magneto switch is right next to the tacho!
The diagram of the hookup on an RV would be very helpful, I dare say electronic tacho’s are very similar in their operation. Thanks, Dave

Unlikley to be connected to the alternator as that has nothing to indicate the engines rotational speed. Magneto, as John says is a posibility.
The alternative, using a sensor may just be the sensing wire(Black) wrapped several turns around an ignition lead. I have a small digital tacho/hobbs type meter where the instructions state 'to wrap it 3-4 turns around spark pug wire'.