Motor Mind B - Please Help...

miniBot

Everything has been working fine for months now, but now both motors are not moving. I have dbl-checked all the wires, here is code that I have been using. I don't know what I did...When you send a command to the MMB, the green lights blink, the motors sound like that they are about to move you can here the gears, but they don't. It feels like the MMB got a command to move and then stop...I've connected a 12v directly to the motors to make sure that they run and they do...I ran the read status code, and got 0 and 0 for status and duty cycle...

OUTPUT· 10
OUTPUT· 11

LeftMotor· PIN· 10
RightMotor PIN· 11

SEROUT LeftMotor,396,[noparse][[/noparse]$55,$88,$7F]
SEROUT RightMotor,396,[noparse][[/noparse]$55,$88,$7F]

Ken Gracey

Hey miniBot,

Change any wiring between now and the last time it ran?
Do you have a scope or DVM to check the signals to motors?
Grounds connected?
Seperate power supplies for the motor and logic? If so, is the motor power supply fully charged?

Ken Gracey
Parallax, Inc.

miniBot

yes and no, the MMBs are on its small own BB, I had to disconnect it from power (a two pin conn) to do some work and then moved it back. after that I checked and it was responding to cmds and I was able to move it fwd and bk. that was 2 weeks ago. This past weekend is when I started to have this issue. at first, it would move the motors for 1-2 secs and then stop them, I whould reset the BS2 and then I whould move the motors for maybe 4-5 secs and then stop. now it doesn't even do that...This is what I see, when I send a cmd, I see the green lights blink, I hear the motor and feel like a stop cmd was send to stop the motors...the MMBs get pwr from a 7805 not the BS2. I've checked the v on that 5v...motors get 12v (thats· 12.2v) and draw about 700ma-800ma each. the fault/red is not on...the only thing new that I did was try to see how the duty cycle option works, I copied some sample code to set it at 88%...Is there any way to set the MMB back at factory ? do you think that might be causing the problem ?· One thing I didn't check is the Break pin, I have never connected that to anything, do you think I should connect that to a 5v ? If so, do I need a res ? I've checked and dbl-checked all the wires...

Ken Gracey

miniBot,

I don't know the MMB very well, but perhaps there's a configuration command stored in the device's memory that's causing the problem. You should be able to clear the memory with a new set of commands. It's probably best to get out the documentation and start from the beginning. Check the documentation for what it says about connecting the break pin. If batteries are fully charged and connections are correct, I imagine the issue lies with the MMB communication.

Ken Gracey