I have a Z-scale railroad set that I’d like to control with the computer. Rather than going to the (rather extreme) expense of using DCC (see various references), I’d like to ask if anyone can suggest a simpler solution.

The locomotive can NOT handle more than 9v DC. From what I can tell, I only need about 1 amp at 9v, but many microcontrollers can’t handle that much current.

There are number of circuits/devices posted on the web (such as http://zthek.com/id64.htm) that use a physical potentiometer to control a PWM circuit, but I am looking for something that I can control with USB.

I tried to rig up a SN754410, but the most I could ever get out of it was about 3 volts from a 9v supply – I’d like to get a full range of voltages between 1.5 and 9 volts.

Any suggestions?

You could get a serial to USB converter cable, and then control any common microcontroller that has PWM, and drive your motors with something like this:

nm-0015

That will turn on and off 9V from the uC’s 5V pwm signal. You just need a power supply that can handle an amp, which shouldn’t be too hard to find.

Seems like there’d be a simpler solution out there.