United Kingdom
Asked — Edited

H Bridge

as im having a few issues using my sabertooth motor controller i was wondering if you have your new h bridge for sale yet ? or , which would be even better is there any way to alter the settings in the modified servo module to work with my sabertooth, ie i can change the values it pushes out if i say press forwards, back etc etc ? is there a config file with those values in ? i must admit i would like to use this motor controller, it cost quite a bit and i have been looking for a use for it, i dont wanna use another of the sparkfun cheap ones, it uses up to many ports and i cant control speed like i want, after burning one up im hesitant at getting another one.

Thanks Kurt


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Synthiam
#1  

It'll be online tonight :)

Doesn't sound like the sabertooth controller is very reliable.

#2  

I see you are out of the cameras. Will the new Motor controller be in a similar price point so I could order the starter kit and just swap camera for controller? I have plenty of cameras, need a good controller.

Alan

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Synthiam
#3  

If you're considering doing that, then you won't need the modified servos either. Might not make sense to purchase the Kit, when all you really need is the EZ-B and controller :)

#4  

Yeah, I think I'll piece part what I need (although I still might have a use for a modified servo, they are not hard to find, or I am sure you will be back in stock by the time I am able to buy. I have two friends that usually exchange pretty extravagant gifts with me, and I added the kit to my wish list. If I don't get from them, I'll be ordering by the end of December.

These are the motors I was thinking of getting. At their highest setting they draw 2amps but I think they'll work for me at the slower setting so I think it might be OK. I am more worried about torque than speed. I am going to be carrying a good amount of weight on my bot.

http://monsterguts.com/index.php?act=viewProd&productId=4

I still may buy a couple of modified servos. I am thinking that I should do a small scale build as a proof of concept and to work out the software before I start building big.

Alan

#5  

Hey Alan,

Just be careful about hooking up the 1.5A H bridge to 2A motors. I you are going to be putting torque on those motors your Ampres start jumping up quite a bit and you could easily hit 2A if you put loads on them or get any momentary stopping of the motors. Not sure what voltage you are going to put on those motors....but you may want to do a test with an Ammeter before you buy your H bridge.

Simply put the Ammeter in series with your motor...and put some resistance on it (hold it with your fingers for small motors) to see what you get.

I have not hooked up an H bridge myself yet but have done some testing and research. In my research I have found that you definitely want to ensure you have some 'wiggle' room and select and H bridge that can handle the current. I did not see it, but maybe DJ knows the max peak current the H bridge he has posted is. It may work fine for you. Good Luck!

Kevin

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Synthiam
#6  

They rarely pop. They just start getting really slow. That's when you shut it down and let it cool. Then think of a better cooling method :)

I ordered a pile of tiny tiny 5v fans. I'm going to start putting fans on the EZ-B optionally... Might be beneficial for motor controllers also

#7  

Thanks for the advice. I was thinking I would use the low voltage (5v) connection on the motor since i think that will give me the speed I am looking for (depending on what wheels I end up with too. Your idea of measuring under load is a good one. I think I will go ahead and order the motors now so I am sure what controller to get when I order my EZ-B

Belgium
#8  

Hi DJ and all the others,

I was browsing through recycled components and came upon this :

http://www.canakit.com/Media/Manuals/UK1122.pdf

Actually it's still brand new in the packaging so I guess it's about time to use it. Any ideas how to connect it to the EZ-B ?

For now I'm testing RC ESC's from Graupner and Robbe. Images :

http://www.flickr.com/photos/phg1961/6381886533/in/photostream/lightbox/

http://www.flickr.com/photos/phg1961/6381887759/in/photostream/lightbox/

I'll have more details on that later on.

Anyway still looking forward when you're releasing a nice (powerfull, something like 5 - 8 Amps) H-Bridge for the EZ-B. I'll be your first customer.

Keep up the good work !

Best regards,

Philip

Btw : some of this text comes from Google translate, so if it sounds funny or doesn't make much sense.... blame Google for it.