Help! Newbie 12v ON/OFF circut

[travis.taylor10ee]

Hello all!
First off, I have researched this topic a bit and I THINK I have what I need.
HOWEVER, I don't want to go charging into the wild blue yonder and fry $20
worth of parts, so I'd like your advice if you'd be so kind!

I'm working on an engineering project for college and I need to power a small
12Vdc (0.5 Amp) gearmotor to agitate an assembly. My question is this..

What would be a good, SIMPLE circuit to power this motor automatically on for 3-5 seconds, then turn it off for around 3-5 minutes and repeat this for as long as a toggle
switch is closed?

Please be gentle, I'm not into electronics much, but need to make everything in this
project from scratch...

From what I understand, a 555 timer circuit seems to be the way to go, yes?

 

[(*steve*)]

3 to 5 minutes is a little long for a 555 timer, but as long as the timing isn't critical, you may be able to achieve it (actually it's a lot long, but aim for the lower end of this range).

The 555 can drive a relay directly (remember a reverse biased diode across the relay coil).

I would operate the 555 from a separate (say 9V) battery to keep the power to it clean. The fact the relay is only energized for a few seconds means the battery should last for quite a while.

 

[travis.taylor10ee]

A reversed biased diode?

 

[(*steve*)]

See bottom of page 12.