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Pololu RP5 motor

Hi there, I have recently bought a RP5 chassis from pololu, this chassis is holding 2 brushed DC motors (6V) and I have some questions: first of all; how can I control it? I mean, do i need to control it by PWM or is just 5v or 0v?

second, I built a little pcb with a L293D to protect the controller (Arduino) from reverse current, is this ok? 

third, I planned to buy this one: http://www.cooking-hacks.com/index.php/shop/robotics/l298-dual-h-bridge-motor-driver.html or this one: http://www.cooking-hacks.com/index.php/shop/arduino/ardumoto-motor-driver-shield.html, which one would be better?


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You can PWM it, you can run it at 5V, but I don't think 0V will do much for you ;) It's meant to be driven at 7.2V. Less voltage means less power and less speed. They are just 280-sized DC motors, no wizardry behind them. More info about them here.

Frits' PowerSlider uses a L293D to run his RP5 but his robot is pretty lightweight. At 7.2V the motors will draw 2.4A at stall. 210mA when free running. At 6V you will consume less current but your L293D will warm up if your motors get stuck.

Of the two shield you are looking at I'd choose the first one. Both can handle 2A per channel which is probably sufficient for everything but a maxed out RP5 chassis. However the first shield has a fat heat sink which is appropriate for extreme usage.

Really thanks for your quick answer, just two comments:

When said 5V I was refering to (5-0) and 0 to (0-5) forward and backward rotation XD

So, I can just connect the outputs of the arduino to the 293 isn't it? But what kind of pins should I use, as I understand if I dont PWM the motors I can use all of them "digital" right? Maybe connecting 7V as Vref to 293 will be better right?


You can use simple "pin high" and "pin low" to get the motors to turn on and off, backwards and forwards. To get speed control you will need PWM and I'm sure specific pins on your Arduino (me, PICAXE caveman, no speaky Ardy).

I don't know what you mean by Vref. Here's how you hookup your garden-variety L293:

The other package has a different pinout but the pin names remain the same. You can just tie the ENABLE lines to 5V if you want to save on pins but you can get braking options if you manipulate them with your Ardy.