BombiniBot Motor Direction
 Arduino   Started by Matha Goram   2017-08-22 13:43:22 -04:00   Comments: 6    Viewed: 165

  1. Matha Goram
    Matha Goram Member

    Since I was experiencing some "proximity" issue with the Bluetooth connection between a Windows host running Scratch and BombiniBot (connection is established via bbpanel but then dropped as soon as Scratch is launched via bbbpanel), I changed over to a very basic example with the Arduino interface.

    The following lines of code make BBot spin in place:

    The following lines of code make BBot travel forward:

    Have I "unintentionally" changed anything in my setup? Are my observations (spin and travel forward) contrary to normal working conditions with BBot?

    Of course, this BBot travels backward with:

    Matha Goram, 2017-08-22 13:43:22 -04:00
  2. seth10
    seth10 Member Staff Member
    I believe the most likely cause is one of the motors being plugged in backwards. Please take another look at the assembly instructions. Make sure your wires on top match the picture exactly, in particular the direction of the red and black wires for the motors.
    Let me know how it goes.
    seth10, 2017-08-23 10:57:56 -04:00
  3. Matha Goram
    Matha Goram Member

    Hello Seth,
    The top view of my BBot is identical to that shown in the attached picture. This BBot was working fine (with the Arduino interface) just a few days ago. As I mentioned in my original posting, the only work that I have done with it after the basic Hello exercise (with the Arduino interface) was to try the bbpanel introductory exercise. This test was inconclusive but is not a concern for now. As noted earlier, bbbpanel would drop the connection once Scratch was launched. But I am not concerned about this topic since I would like to focus on resolving the Arduino challenge.
    I feel that my issue is "some operator" error because everything was working fine just a few days ago. All I have done since then is to try bbbpanel and recharge the batteries. In the process, I did disconnect the left motor connections at the top retrieve the rechargeable batteries but I reinserted the cable exactly as shown in the assembly diagram. The BBot was "factory assembled" so I am assuming that I do not have to investigate the wires at the motor end (besides it was working properly before).
    Since I am clueless about EE functions, I wonder what I could have done to reverse the motor movement. The cable that was removed (to extract the rechargeable batteries) was for the left motor. It is this left motor that is displaying the reverse rotation with positive values of motor speed and forward rotation with negative values. The right motor is performing properly without the need to invert the speed value.
    Is there some kind of firmware update that I need? I scoured the web site but could not locate the latest firmware update for download. There are published instructions for the firmware update but I do not have the corresponding binaries. Would you recommend this course of action (assuming that I can get access to the latest firmware)?
    Matha Goram, 2017-08-23 18:19:53 -04:00
  4. seth10
    seth10 Member Staff Member

    We do not provide firmware files on our website because, in the vast majority of cases, a firmware overwrite is not necessary and is likely to cause more problems.

    I am not sure as to why it would have that direction issue. Could you try plugging in the left motor the opposite way? Perhaps it was plugged in "backwards" before you disconnected it to access the batteries. Even if it does not then match the assembly instructions, if flipping the wire of one of the motors is all it takes that would have the least possibility of unintended side effects.

    seth10, 2017-08-25 10:40:21 -04:00
  5. Matha Goram
    Matha Goram Member
    Hello Seth,

    No luck with reversed connection to the top terminal for the left motor. The correct way (per documentation) is with the white wire on the left/outside. Reversing it with red outside and white inside did not result in a reverse operation. The strange part is that with the cable (for the left motor) disconnected, the result/effect remained unchanged. The left motor spins even with its cable disconnected.

    Anyhow, please close the issue. I will use separate/independent variables for the motor speeds to accomplish my starter exercises. Thanks all the same for taking the time to follow-up with my questions.

    Matha Goram, 2017-08-25 12:16:26 -04:00
  6. seth10
    seth10 Member Staff Member

    Oh no no, just the black and red wires! The white/yellow/black/red cables are for encoders, not the motors, those will most certainly not work backwards. But the motor power wires (sorry I should have been more specific there) you should be able to just flip to change the direction.

    seth10, 2017-08-25 15:08:25 -04:00
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