Help with mosfet shield

[scott216]

I am trying to get the mosfet shield to power a small hobby motor, but I don't know how to wire the motor in.  Does the 3-position screw terminal block act as a switch or does it provide power to the motor.  Either way, how should I wire up the motor.

[digistump]

I've added a hook up diagram: http://digistump.com/wiki/digispark/tutorials/mosfet?&#hook-up

[scott216]

That's a big help.  Thanks!

[scott216]

I've added a hook up diagram: http://digistump.com/wiki/digispark/tutorials/mosfet?&#hook-up

http://digistump.com/wiki/_media/digispark/tutorials/mosfet-diagram.jpg?w=400

If I wire it this way, I assume this is also providing power to the digistamp, so I don't need to power that also.  Is that correct?

[dougal]

I'm pretty sure you have to power the spark separately. My question is whether you need to connect the spark ground to the power load ground, or if the shield does that? (my analog circuit knowledge is spotty and rusty, but I seem to recall that you usually have a common ground, yes?)

[scott216]

I'm pretty sure you have to power the spark separately. My question is whether you need to connect the spark ground to the power load ground, or if the shield does that? (my analog circuit knowledge is spotty and rusty, but I seem to recall that you usually have a common ground, yes?)

That's a good question about the ground.  After I noticed the input voltage for the shield could be up to 60v, I realized the digispark would be powered separately.

[digistump]

Digispark must be powered separately


Grounds are tied together on the shield

[Mark]

The Mosfet shield is switching a ground.
In order to complete the circuit for the load and the switching of the fet, both grounds need to be tied together.

This diagram showing a 12v load being switched may help


Mark