Dawn Robotics Forum

Hi! My first post is nowhere to be found so I am posting again. I recently obtained the Dagu Mini Driver board based on the Atmega8 and uploaded the code from the getting started tutorial, the one that makes it go it a square. It uploaded perfectly.

Then I attached a 4x AA battery pack to the battery header connection, observing polarity. My multi-meter read 6.31v for the batteries...good to go . I also attached these motors(link bellow) to ML and MR headers. I powered the board on, but the motors didn't budge. I uploaded the blink sketch to make sure the bootloader was good and it uploaded perfectly also. So I uploaded the old code again. I let it sit for a day.

The next day I tried with a different motor and it worked! I thought, maybe I did something wrong the first time or something. So I attached the wires back to the original motors and tried it. They worked also! But after about 5 minutes of non-continuous driving they stopped moving. It wasn't sudden, it was after turning it off, and then on again. I tried the other motor that is had started working with and it did not work either.

I assure you the connection to the motors was secure. Also, the light on the board, the red one, always lights up.

So, as you can guess, I am totally confused. What could the issue be? The only thing I can think of is to high of a stall current maybe?

Link to motors I used:http://www.allelectronics.com/make-a-store/item/dcm-427/6-12-vdc-motor/1.html

Hi there,

Welcome to the forums. Many apologies for the delayed reply, I had a massive cold/lurgee last week, and am just trying to clear my backlog of things to do.

I'm not sure what issue you're seeing here, the motors that you've linked to don't look like they'd trouble the mini driver too much.

Can you please confirm that the wires for one motor are just attached to one side of the board? i.e. both wires only connected to ML or MR? Also, do any of the transistors or solder joints on the lower half of the board look as if they're damaged?

Regards

Alan

Hi! Sorry about your cold! Hope you're feeling better!
I am not to good at telling the condition of surface mount pieces and as they say...a picture is worth a thousand words... so here is my setup:

http://www.filedropper.com/img9759
http://www.filedropper.com/img9763

If the links don't work I can email them. I wired the ML header to one motor(one pin to each side of motor) and the MR to the other motor(again one pin for each side of the motor). The only other wire connection is the battery which I observed polarity of.

I have a multimeter by the way if that would be of any help in troubleshooting!

If the link above does not work try this one:
http://wikisend.com/download/211422/IMG_9759.JPG

Hi there,

Your wiring all looks good. What kind of batteries are you using?

I am thinking that if the motors turned for about 5 minutes then it might be a problem with the batteries going flat. The demo program will turn the motors back and forwards as it drives the robot in a square so you might want to modify the code to just fix the motor speed to see if that makes any difference.

Do you have a fresh set of batteries that you can try? One thing to check would be wether the voltage between a 5V line and GND stays around 5V. If it dips too far below then this could cause the Atmega8 chip on the board to reset, and stop the sketch from working.

Regards

Alan

Ok...my batteries are measuring 6v with my multi-meter and run the motors fine if I attach the battery pack directly to them but I will try some new ones. Would a 9v battery be ok for testing? I know long run that they have very small MAH but for testing is that too high?

For checking the 5v and GND, do I just attach a probe to GND pin and one of the 5v break out pins from the servo motors?

I put in a new set of AAs but no luck. Tried a 9v battery but the motors wouldn't turn either. Tried micro-motor that shouldn't take much to run...no luck:(. Haven't tried modifying the code yet...

I measured from a 5v pin from the servo breakout and GND and it gave a constant 5.031v. I held my multi-meter there for a at least 60 seconds and it gave that constant voltage.

Is there a way to measure the motor pins to check if they are getting a signal? I don't want to do it without correction instructions because me and my multimeter have a love/hate relationship. I fried a DC power supply adapter while trying to measure the current for example:O.

Sorry, I just can't think of anything besides that! Got any ideas?

Any ideas?

I tried again recently and it still doesn't turn:(.