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Scribbler Robot Motors Stopped Working — Parallax Forums

Scribbler Robot Motors Stopped Working

bubby9534bubby9534 Posts: 36
edited 2011-09-09 06:44 in Robotics
I have a Scribbler Robot (the first one) and the motors stopped working. I tried restoring factory defaults in case I had messed that up but that didn't help. I took it apart and everything looks just fine. I cant even hear the motors trying to run :frown:. Everything else works fine. Any Ideas?

Comments

  • Martin_HMartin_H Posts: 4,051
    edited 2011-09-05 19:37
    They're brushed motors so there's likely some contact problems. Read this thread and see if the tips help:

    http://forums.parallax.com/showthread.php?133802-Scribbler-Motor

    If that doesn't help, you can replace the motors. I had to do that with my Scribbler and I ordered this one: http://www.pololu.com/catalog/product/604. I should have ordered a pair as an old/new motor combination isn't the greatest match.
  • ercoerco Posts: 20,256
    edited 2011-09-05 19:57
    Unlikely that both motors stopped working at exactly the same time. Did you open the case and unplug a connector? Can you still program it? Stamp recognized? Install brand new batteries. Run the last demo program in the startup guide (ambulance behavior) and make sure your LEDs and speaker work. Open the case and while it's running, measure voltage at the motor terminals.

    Edit: Also check the stall sensor status. Is pin 7 high or low when the motors are "on"??
  • Martin_HMartin_H Posts: 4,051
    edited 2011-09-06 06:33
    Good point Erco. I've been fooled by low batteries a few times into thinking there were other problems. Everything works fine, but when the program issue a motor command it causes a brown out. This resets the processor and the program starts at the beginning. Adding a distinctive alert tone sequence on power up helps detect this scenario.
  • bubby9534bubby9534 Posts: 36
    edited 2011-09-06 10:15
    I found out that the left motor was simply unplugged for some reason. However, the right motor still doesn't work. I took it apart and tried spinning it etc. I do have fresh batteries and the other components such as speaker do work. I tired plugging the working left motor into the right motors slot, and it didn't spin. So apparently there is no voltage coming through the right motor pins.
  • ercoerco Posts: 20,256
    edited 2011-09-06 10:29
    Didja measure the voltage going to the right motor?

    Unplug that motor from the robot and put 3-6 volts on it and see if it turns.
  • bubby9534bubby9534 Posts: 36
    edited 2011-09-06 11:01
    It turns.Besides, that "broken" motor works if I plug it into the other motor's port.
  • Martin_HMartin_H Posts: 4,051
    edited 2011-09-06 11:16
    If I have this right, both motors work in the left port, and both fail to work in the right port. One thought it that the program is only sending a command to turn one motor. But you said you restored factory defaults, so I think that is unlikely.

    But there are values in the EEPROM which are used to adjust the relative speed of the left and right motors. They are not over-written when you restore the factory program. I wonder if a bad value got stored in the EEPROM if that could confuse the program to not turn the motor.

    It's been a while, but I know the GUI lets you upload a calibration program to Scribbler. Does it have a way to clear the EEPROM settings?
  • ercoerco Posts: 20,256
    edited 2011-09-06 13:17
    Sounds like you've opened your Scribbler up several occasions. It's possible you disconnected something and forgot to reconnect, or connected something wrong. In the latter case, there may or may not be permanent damage.

    Suggest you methodically trace the right motor wires back through all connections and boards to the motor driver circuit. Find the BS2 pinout connection to the right motor (pin12) and see if you get 5V to it when you make it high.
  • Ken GraceyKen Gracey Posts: 7,392
    edited 2011-09-06 13:53
    bubby9534,

    We're offering dealer financing and no-interest loans on the red S2s these days. We even offer protection plans for an extra $25/Scribbler. I think the guys in back have added an undercarriage coating process as an upgrade, too.

    Truthfully, let's get you a shiny new S2! From a distance it looks like the forum members have done everything we'd suggest, so there's no point in keeping the patient open on the operating table. In this case it might be best to use it as parts.

    Send me an e-mail with your shipping address to kgracey@parallax.com and we'll bring this to a happy ending. As long as you're not expecting overnight shipping to Dunedin, New Zealand we can have this issue closed up today.

    Ken Gracey
  • ercoerco Posts: 20,256
    edited 2011-09-06 13:57
    Boy, Ken makes it tempting! Sure, get your shiny new red S2, but never give up on old blue. You can still learn a lot from the old boy.
  • Tony B.Tony B. Posts: 356
    edited 2011-09-06 15:22
    Now that's what I call standing behind your product and customer service! Way to go Ken!
  • bubby9534bubby9534 Posts: 36
    edited 2011-09-06 15:47
    I have reset everything to defaults, cleared EEPROM settings, checked the motor itself, and yes the batteries are fresh. So this traces down to the circuitry in the Scribbler itself. What could have gone wrong on the board that would cause the connection to the right motor pins to stop? I may have to admit defeat and get a new Scribbler. How does the difficulty of PBasic and Propeller programming language compare?
  • Martin_HMartin_H Posts: 4,051
    edited 2011-09-06 16:20
    Go for the red S2. You can still use the GUI and Spin is a fairly straight forward language. I picked up a copy of Harprit's book (http://www.amazon.com/Programming-Propeller-Spin-Processing-Electronics/dp/0071716661) and was off to the races in a few evenings.

    Spin is block structured with global and local variables, so it is a more modern language than PBASIC. Once you get comfortable pulling down code from Obex (the link in the navigation above), you can do a lot fast. The only real beef I have with it is >= versus => and lack of types.
  • mindrobotsmindrobots Posts: 6,506
    edited 2011-09-08 17:33
    Bravo, Ken!!

    Coming through in true Parallax spirit. Everyday, your company does something above and beyond the call to impress me and make me glad I do business with you guys!
  • Matt GillilandMatt Gilliland Posts: 1,406
    edited 2011-09-08 20:11
    So bubby9534 - did you get in touch with Ken?

    He'll set you up with a bright shiny new S2!. Ken has the propensity for doing this every so often - strike while the iron is hot!
    -Matt
  • ercoerco Posts: 20,256
    edited 2011-09-08 20:15
    Hey Matt & Ken: I have 3 blue Scribblers that all suddenly stopped working. Honest injun!
  • Matt GillilandMatt Gilliland Posts: 1,406
    edited 2011-09-08 20:40
    Erco -
    nice try.
    -Matt
  • SapiehaSapieha Posts: 2,964
    edited 2011-09-09 00:51
    Hi Matt.

    I not have any Scribbler.

    So it is not only motors that will not work -- It is entire Robot that stopped working

    Matt Gilliland wrote: »
    Erco -
    nice try.
    -Matt
  • Matt GillilandMatt Gilliland Posts: 1,406
    edited 2011-09-09 06:36
    Hi Sapieha-
    I can see that erco has pulled you over to the "dark side"...resist! again I say, resist!
    -Matt
  • SapiehaSapieha Posts: 2,964
    edited 2011-09-09 06:44
    Hi Matt.

    Some times it is next impossible to resist!

    Matt Gilliland wrote: »
    Hi Sapieha-
    I can see that erco has pulled you over to the "dark side"...resist! again I say, resist!
    -Matt
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