I would think that weight may be an issue with turn, I’ve got stationary turns and moving turns working as a tank ie opposite direction for stationary or slow dow one side speed up the other for moving turns. But I am using newer solarbotics standard motor with 6.5 V to the motor driver.

I would also advise on suppressor caps on the motors, they will also add some life to the motors. I’d be aiming at 6- 7.5 Volts for the voltage to the motors. Some drivers will drop some and so the voltage at the motors is less than suppplied.

Have fun with Pedro!

Dave

I disabled everything in the BIOS and Device Manger, but same issue.

I wiped and installed Windows 7 and tried it right away and it was working perfectly.
But then, I installed everything else including drivers and the problem was back worse than ever.

It was when I uninstalled the video drivers and went back to VGA that I found the culprit and this led me to your post.
I was going to leave it on VGA and be without graphics performance, aero etc, but now I can have both.
You rock. Thanks heaps.

TTT

Here’s WPT’s window with ndis.sys DPC spike:

http://img263.imageshack.us/i/wpa.png/

That was one of these spikes:

http://img697.imageshack.us/i/dpcwirelesson.png/

Then, you disable the wireless card and get almost no DPC spikes ( that little spike’s maybe caused by nvidia powermizer?)

http://img695.imageshack.us/i/dpcwirelessoff.png/

I too own an M1530:
Mine has a 2.2Ghz Intel C2D proc.
2 GB RAM
Intel 4965AGN wireless card
nVidia GeForce 8600M
etc..

I did the Windows Performance Toolkit thing just to find out its ndis.sys the process thats making my M1530 have high DPC spikes every 10 seconds or so..

The Max actual duration shows 6+ seconds on “function” 0×890086b8 and 1.5+ seconds on function 0×89008945.

Searching on the internet makes me think its not an nvidia or intel (wireless) process, but rather one that comes with windows wich makes me think I cant uninstall it for example.

Btw, when I disable my wireless card some spikes (the bigger ones) go away.

Im gonna try and see if these spikes relate in any way to Nvidia’s powermizer..

Other than that, dunno what to do.

Any suggestions?

Alex

I’m a newbie to much of this myself, but I think I can answer your question: Basically, the less amperage the motors pull the better. Ideally you want to remain as far below the current limit of the motor shield as possible. As you start to get closer to the 1.2A peak (and 600mA operating) limit, you run the risk of burning out the motor driver chips on the shield. I mentioned it as something to consider because although it appears to be working well for me, I am getting close to the current limit of the motor shield and your mileage may vary.

There’s definitely a relationship between motor speed and voltage. Basically the higher the voltage the faster the motors spin, but the trade off is that the motors draw a proportionately larger amount of current. Push it too far, and the motor shield simply won’t be able to handle it and the driver chips on board will burn out.

As I said, I’m a bit of a newbie myself so I can’t offer anything more scientific than that. I discovered what worked best for me by basically piling some weight on the base, and powering the motors with my variable voltage power supply. I checked to see if it could carry the weight, and use a multimeter to check how much amperage was being pulled by the motors at different voltages.

If your interested, I’ll be posting over the next few weeks / months about the build of my robot here:

Pedro2 build log

In your post, you say “The Motor Shield has a max current of 1.2 amps per motor. I did some testing and couldn’t get the motors to pull more than 700mA so I should be OK, but it is something to consider.”

Can you elaborate on that? Specifically, 1) do you want each motor to pull more than 700mA and if so why? 2) Why is it something to consider? 3) Is the lower amperage affecting the bot’s ability to carry a heavier load or move faster?

One other question… what is the possibility of using stronger motors?

Thanks for your insight!