DSMC + Twin Motor Gearbox + OOPic =?

I’ve got a Dual Serial Motor Controller, a Tamiya 70097 twin-motor gearbox, and an OOPic-R microcontroller. How should I power my motors?

-I started with one 4-pack of AAAs, but unfortunately, the DSMC has a minimum of voltage of 5.6, and my NiMHs were just under the limit…

-I put a second 4-pack on in parallel (measured around 10v), and everything works okay as far as sending commands goes. But even at really slow speeds, the controller goes into thermal shutdown after a just a few seconds…

What SHOULD I be doing here? I just figured I’d ask before I did anymore soldering! :slight_smile:


(Your two packs must be in series if you are measuring 10V.) 10V is very high for the twin-motor gearbox motors. You should try to use 5 NiMH cells to get around 6V, which is more reasonable. However, the motors can still draw a lot of current at that voltage (in excess of 2A, while the motor controller is rated for 1A max).

You can try applying a heatsink to the motor driver chip (the bigger chip of the two) to keep it from overheating, but you still need to keep the current within limits. Using the higher gear ratio typically helps, as does keeping the gearbox clean.

- Jan

Yup, I meant to say series (I wanted to increase the voltage to get above the minimum, and I had an extra 4-pack on hand).

More questions:

I’ve also got a second DSMC and one Micro DSMC lying around…

Would it be advantageous for motor power and/or longevity of charge to wire a DSMC (with dedicated power supply) to each motor,


Can I achieve similiar results with one controller/less batteries?

I guess my only concerns are speed/power of the motors and longevity of the charge. I’m not afraid of using lots of batteries if it will get either of those accomplished (but I don’t think I’m ready for the high-power motor controller, either - you guys have enough of my money for now :wink: :smiley: )

So given the components I have (DSMC x 2, MDSMC, OOPic-R, tamiya twin gearbox):

  1. How would you recommend I power the motors?

  2. which controller(s) should I use, and in what configuration?

thanks much!


I am also using an OOPIC-R with the DSMC. Does anyone have a programming example for me to look at?

How would an OOPIC-R with it’s special motor commands handle a DMSC to do the same thing as the Parallax Basic Stamp example in the DSMC documentation.,

I can give more information if necessary.


The Basic Stamp Example in the documentation is very clear and uses the serout command.

Does the OOPIC Syntax have an equivalent command?



This answer was provided by Kit Morton on the OOPIC site.

So I don’t need any more help at this point.



Here is some code for this controller that I got out Gareth Branwyn’s
book, The Absolute Beginners Guide to Building Robots.

'A motor control program using the Pololu
’micro dual serial motor controller and
’the oSerialx object.

Dim S As New oSerialx
Dim R As New oDio1

Sub Main()
R.IOLine = 31
S.Baud = cv4800
S.IOlineS = 30
S.Operate = cvTrue
R.Direction = cvoutput
OOPic.Delay = 50

R.Invert 'Invert reset pin

'Motor 1
S.Value = 128 'Start byte
S.Value = 0 'Device type (motor)
S.Value = 0 'Motor and direction
S.Value = 127 'Motor speed (between 0 - 127)

'Motor 2
S.Value =128 'Start byte
S.Value = 0 'Device type (motor)
S.Value = 3 'Motor and direction
S.Value = 127 'Motor speed (between 0 - 127)
OOPic.Delay = 500

End Sub