Motor control pins - bad?

[johnny555]

Hey Alan -

Thanks as always for non-stop support on these forums; always helpful!

An issue I'm having - the pins on the mini driver board for the right motor don't seem to be outputting anything. I've gotten basically everything else working - video streaming, pan/tilt operating, and left wheel running. But the other wheel seems to be dead in the water.

(Confirmed it's not the motor by hooking it up to the left motor pins, which worked).

Can you think of any troubleshooting I ought to start with?

And if the board itself is suspect, is an UNO R3 a potential replacement? Just seeing if I can get around another purchase... Thanks!

John

[Alan]

Hi John,

Can you check that the jumpers on the pins D7 to D10 are in place? As these connect the Atmega8 microcontroller to the h-bridges on the mini driver.

Next, you could try running the simple sketch given in this blog post on the mini driver, as this doesn't do much else apart from make the motors turn.

You can also have a look at the transistors close to the motor output pins. These form the h-bridges and if any look damaged or missing then that may explain why the motor output isn't working.

If it turns out that the h-bridge is damaged then you can either try to replace the transistor (ninja soldering skills needed) or else replace the motor driver with a separate chip such as the L293D. I can provide details on how to do this if needed.

Regards

Alan

[johnny555]

D10's jumper was out of place! The mini driver board had lost its bootloader, and I had to burn it back on, which had me connecting to that D10 pin. Anyway, nice catch!

Still struggling with power issues; the 6 AA battery pack seems to only power everything when it's fully charged, otherwise the Pi_Mini_Bot network doesn't show up (using the recommended Edimax; I don't have the UBEC). I think I better step up to the USB power bank. It's meant to power the whole setup, yes?

Major thanks for the fast reply!

John

[AverageMan]

Hi John

I'm powering everything off a powerbank, it does work. I use the 2amp output for the mini driver, and the 1amp output for the Pi. Works good, lasts ages and is easy to charge. I've opened mine up, drilled holes and mounted it on to the chassis for a more permanent solution.

Only thing to consider that I've picked up from here and Twitter, is that you may get more speed from batteries as they will provide more voltage (powerbank is something around 5V I think)

Rich