Help needed with circuit diagram.

Hi. This is a question for the guys with some electrical 'know how'.

I am going to make a Spirograph, so my kids can use it to make pretty patterns on the walls.

I know that it consists of two motors with mirrors on them, set at the correct angles.
However I want to be able to control the speeds of the motors with thier own pots. Each motor will have it's own on/off switch too.

Attached is the curcuit diagram I have drawn.
Even though I assemble PCB's for a living, I don't know anything about actually designing electrical curcuits.

What I need to know is...
1. will the curcuit I have drawn, work as it is, or do I need to add any other componates and if so, where?
2. what value pots would be required to slow the motors right down?


Eventually I'd like to add a curcuit that would run both motors at constantly changing variable speeds so that I don't have to adjust the speeds via the pots manually to make different patterns. But one step at a time  

Thanks.

Hey mike666.... yes... your circuit drawing would work...

The Potentiometer values would depend on the motors you are using...
but with small dc motors... you could probably use a 100 to 500 Ohm pot..
You'll need to experiment.

I'm sure there are members here that could shed some more light on this...

Jerry

That may work, but it may be a bit rough depending on matching the motors, pots, and voltage in - and remember you'll need pots that can take whatever current the motors need.

I tend to over-complicate things though, so maybe just any old pot/motor/battery combo will work ;-)

Maybe a modified laser driver would suit you better - like a "DDL driver" (but I'm forgetting if current control works well for motors).

Better yet would be a pulse-width modulator (link) for each motor... though that may be overkill.

Did you do a search on "spirograph" on the forum? I know this has been done before...

 
DanQ

I have done this for a quick and easy spirograph. I used 3 12v motors, and 3 pots (150 ohm) that were high current wirewound pots, salvaged from an old TV. This keeps it pretty simple, your diagram will work. I went with the wirewound pots (same size as regular pots) because they have to carry the current that the motor needs.

Thanks for the advice guys.