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DIY H-Bridge for Tamiya double motor gearbox

Newbie alert!

Hi all,

First forum post here. Go easy on me. I have not been able to find a solution to my problem in the forum, (even though a couple came close) so I´ve decided to go to the source.

Is this http://letsmakerobots.com/files/H_bridge_single_relay_DPDT.pdf a good H-Bridge to use with the Tamiya double motor gearbox? If not, can someone point me in a better direction?

My apologies if this has came up before and I have failed to find it.

Cheers,

Andrés 

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I've also made a motor driver board like that some time ago: http://www.franciscodias.net/boards/motor-driver-board

I've never tested it with the Tamiya double motor gearbox, but I've successfully controlled two motors which could be controlled by the L293D as well: http://letsmakerobots.com/node/22906

Prezado Francisco,

Obrigado pela sua resposta!

I like your H-Bridge design. I will give it a try if things don´t work out with the pyro guy´s design. You see, I have already purchased all components.

Andrés

Finding a schematic for an H-bridge is like trying to find a recipe for apple pie. There are 1000's, all pretty much the same and some are better than others. I am not in a position to suggest the "best" one but at first glance, I see nothing wrong with your second link --the pyroelecto link.

I don't however like the first link you had with the relay shenanagans.

More so, the fact that the pyro guy has gone so far a to make his own PCB, most likely proves that A) his circuit works and B) he took the time to fix all the bugs before going to all the trouble to make a PCB.

Sure --go with the pyro guy.

The wise-man said:

More so, the fact that the pyro guy has gone so far a to make his own PCB, most likely proves that A) his circuit works and B) he took the time to fix all the bugs before going to all the trouble to make a PCB.

This might be the best bit of wisdom I've read today - it's the kind of obvious reasoning that I'd never come up with for myself.  Thanks for a useful clue.

Those little gearboxes don't draw very much power at all. The 293D will work just fine with them.

Good to know. Thanks.

I see your point, Chris. I will go ahead and assemble the pyro guy model.

I want to thank you profusely for taking the time to help me out!

I should add that the "Pyro" board is a pretty beefy board. It says it is good for 10amps --and you could probably squeeze more out of it with some heat sinks. It is MORE than enough to run your little gearbox. The good news is if you ever move up to a bigger robot, you already have a motor driver capable of driving some pretty big motors.

Good luck, my friend.

Hey Chris,

I managed to get a L293D locally. (Was not easy). The factsheet says it can only handle 0.6A on the motor outputs. Do you believe this is enough for the tamiya motors?

On the other issue, I will go on and make the pyro H-Bridge just for the fun and experience of it.

Thanks. Cheers.

Andrés 

The link you show is not really the "standard" way of doing things. It would work but if you are just starting out, is way more complicated then it really needs to be. Instead, I would look at a motor driver chip such as a L293D. This guy is very "standard", cheap, and well-documented. FYI --This chip basically has the schematic you show, all stuffed neatly inside.

There are also countless "motor driver boards" which make connections a bit easier. Not hard to find --just about every robot shop will carry something for driving small motors such as yours.