Relays (DPDT)
Relays are an alternative to motor-controllers.
They do consume a little power from your battery when in either on or off position (turned on) - but they also do deliver the full power that you want - where a motor-controller often takes some of the power (voltage-drop).
They can be found to be able to handle much more current than a motor controller matched in size (and price).
They are "slow". That is; You can not do PWM with them (Slow the motor down by just giving it pulses) - but then again you can, if your robot has a little inertia (is moving forward) - then the on/off speed of the relays is way fast enough to slow down / drive half speed etc.
They can be found in a million configurations.
One very common and useful is a standard 5V DPDT relay that can be found anywhere. 2 of those can make a motor reverse / turn on / off.
@ Thu, 2010-05-06 15:03
Latching relays
Probably worth mentioning latching relays here for those who don''t know about them. I used one on THIS project.
A latching relay has two coils and the contacts can be toggled from one state to the other by pulsing the coils. The difference is that a latching relay will stay in the state it's in - It's a relay with a memory.
They're a bit harder to find than standard relays (Farnell do them) but they are worth bearing in mind.
Andy.
@ Thu, 2010-05-06 15:34
Oh, thanks. i guess that is
Oh, thanks. i guess that is pretty smart, because they will consume no power then.
So in many ways / in some situations, this will be the best solution, even over motor drivers!
Thanks.