Let's Make Robots!

TAMIYA twin-motor gearbox

Vendor's Description: 

This is a very nice little package. You have to assemble yourself, and there are 3 ways.

You want to assemble in "C"-mode, ratio 203:1

The A & B setups, 58:1 are really fun because they are fast etc.. until you try to make your robot use it. It is simply not strong enough for the fast-changing pulses etc from a PIC-controller, it is useless because it takes so much time to accelerate, and many setups will not ever get up to speed at all.

I strongly recommend that you buy some TAMIYA wheels or belt-tracks to accomplish, and also other parts in this series from TAMIYA, the plates, sticks etc.

You should check this link: http://www.pololu.com/docs/0J11

Here is a robot driving one of these http://letsmakerobots.com/node/386

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So how exactly would i do that?

Just switch wires?

Or do i need to program my Picaxe for that?

Still waiting for my Picaxe to come in the mail, along with other things.


Either way will work. Switching the wires will be the easiest way to do it, but otherwise, just tell the picaxe to run them in opposite directions.

Aarh.. instead of re-wiring, I would say that changing 2 digits in the code would be easier. It is either

high 4 low 5


high 5 low 4

that will make it turn the right direction.

(Or high 6 low 7 / high 7 low 6 if it is the other motor)

So, every time you use your gearbox, you will have to remember that turning on port 5+6 makes it go backwards and 4+7 forwards, instead of remembering that turning on the even ports makes it go forward and odd ports makes it go backwards. I find the last easier to remember and I will gladly use a couple of seconds with a soldering iron to fix that.

Well.. of course if you "only" have 1 gearbox and always use it in the same way, I see your point. Then you can solder it so it fits like a lego-brick, and your code can be the same for every robot you make with it.

The reason for my thinking is, that I have many gearboxes, and even more little geared motors, and even more smaller geared motors. And I hook up things differently, sometimes through this, sometimes with that, and sometimes both and often something else.. :)

So I can never just use the same code, or trust that the wires are hooked up the same way. Sometimes I use 2 motors on one side, sometimes I mirror a motor etc.

So I always have to adapt something. And if I always had to adapt by re-soldering, compared to what I do; Write my code so there is only one way to change one digit.. it would be a lot of soldering.. and possibly the same amount of adapting the code, because I make new hardware setups every time :)

To put it short; Whatever :D

Tanks for the reply.

Switching the wire seems easier, since i haven't built it yet.

But it's good to know i can do both, just in case I have a momentary lapse of reason and forget to switch the wire.


Oops - I stole the picture from somewhere on a google-search. Illegal and all.. And now I am getting for it, the picture has extras on it!! :D Well then, there you go, you can also add encoders.. aparently!


/ Frits 

Yeah I thought so... those solder joints where much too clean to be made by you :-D

You can see the encoders here:


- Jimmy

I just assembled mine; I also opted for the C configuration. Next step is the wheels and the belt tracks. Then I need to find a plate or something to mount it on, but that shouldn't be hard. Thanks for posting the picture, so I don't have to take any. Did you take the picture? What are the red/white/blue wires on the left side for?

My guess is that those wires are for encoders (I think you can see some circuit boards in the center).

- Jimmy