5v logic to control larger motors

[JonnyMcJonny]

I had an idea for a project and was wondering how I'd go about using 24v motors controlled by 5v logic circuits.
My current plan is to use 2 seperate power supplies, one for the motors and one to power the microcontrollers and such, using small servo motors to operate mechanical switches that control the higher voltage motors.
I'm sure there must be an easier way though, anyone got any better ideas?

 

[(*steve*)]

you will need two separate power supplies, but there are few reasons one cannot be sourced from the other.

In other words, you have a high current 24VDC power supply and this powers a relatively low current 5V power supply.

However, one of those few reasons is heavy ground current.

If both power supplies share a common ground, the current drawn by one could have a significant effect on the other.

2 completely separate power supplies that have their grounds linked at a single point (close to the interface between the two -- say at the power mosfets) would be one way of minimising this issue.

Another way is to have a single point where the supplies share a common ground (at the regulator) and then optically couple the logic signal to drivers operating from the higher supply rail.

If the current demanded from the 24V rail is relatively low, and/or if you can arrange to have a very low impedance ground, the problems may not arise.