H-bridge for 4 motors - robot car

Question

I understand how to connect a IO tiny, ez-battery, ARC , H-bridge motor controller to two wheel robot car, easy.

Now I have a robot car that has 4 motors, do I just use 2 H-bridge controllers?

Or is their something I am missing?

thanks for help

Ang

robo rad · Answer

You could just wire the front left and back left motors together at the left motor output and then do same for right front and back together at right h bridge motor output.

EzAng · Answer

So in the H-bridge, just put one wire over the other for left and right The h-bridge only has two places for motors   I thought that, it just sounded too simple, thanks

Dave Schulpius · Answer

Ya. I'm sure this could be done. However make sure you are not overloading the H-bridge. Look to see what the peek amp draw is on each motor then double it. If it's at or over what the H-Bridge is rated for then you will burn out the H-Bridge.  Also all motors are not created equal. Even if they are the same motor. if you feed both the same current one will probably run a little faster or slower then the other. This will make it difficult to keep the car from driving straight. You may be happier with a motor controller that offers two channels and provides a mixed or tank setting. The motor controller will then do all the corrections and smooth turning for you. Depending on your budget consider a Sabertooth. ARC has a Sabertooth control built into it. A little less expensive alternative Motor Controller would be a SyRen 10A regenerative motor driver at $50 USD. However this is still a little pricey for a toy if that's what you're building. It's made by the same company as the Sabertooth and should work with the controller in ARC. There are probably less expensive MC's that would work also. You could easily turn this into a money pit and drop 100's of bucks into making this car precisely controlled. Where are you going with this build and what is your budget?  You say you have 4 motors you want to control? Is this a 4 wheel drive car and do you need and want 4 wheel drive? Perhaps you can remove the two rear motors and make control less expensive and easier.  With a quick google search you can find lots of information about powering and controlling 4 wheel drive cars. If you still want all 4 motors here's a great thread right here on this forum you should read. Towards the end (Post #28 and beyond) you see you can run many motors from one Sabertooth. Richard R really lays it out for us. Looks easily done. https://synthiam.com/Community/Robots/Making-Of-4-Wheel-Robot-534/comments

EzAng · Answer

Thanks for your input, this is just a cheap project to test the H-bridge -works well. I thought about the overloading of the H-bridge the way robo rad suggested I guess the simple way is to just use 2 motors on the 4 wheel car for now. Don't need 4 wheel drive, lol Thanks again, Ang

DJ Sures · Answer

Do what David said and hook the two motors on each side together. It’ll be fine.

EzAng · Answer

I tested my H-bridge, L298N Motor Drive Controller Board Module, Io tiny, Ez-battery - 4 motors, wheels hooked up, run well, straight, fast. want to see a video?

Nomad 6R · Answer

EzAng yes video please.lol

Dave Schulpius · Answer

Outstanding. Yes, please do a vid. Show how you wired it also.

EzAng · Answer

Ok  Here is my car going "slow" for this video Parts:  IO tiny,  ARC,  Ez-battery -  L298N Motor Drive Controller Board Module Dual H Bridge DC Stepper on Amazon, you can get 5 of them for  12.99    I connected 2 motors to one side, and 2 motors to the other side that's it! Ang

Dave Schulpius · Answer

Very nice. What fun!! Thanks!!!

Nomad 6R · Answer

reactions on youtube channel is dissabled?

EzAng · Answer

Here is a picture of wires: I do this not so much for the toy aspect, but to learn wiring, h-bridge, all the rest

EzAng · Answer

nomad, I just clicked the video, it plays here looks like Dave Schulpius seem it also

EzAng · Answer

for now, final picture of car, 4 motors, IO tint, ez-battery, H-bridge:

Nomad 6R · Answer

love transparent parts.good speed too.:D

Nink · Answer

Hey @EzAng did you ever do 2 hbridge off the iotiny? I see above you used 1 hbridge and bridged across 2 pairs of motors. Trying to work out if I have enough ports on the IoTiny to run all 4 motors separate as I don't have a sabertooth :-(

DJ Sures · Answer

A Two channel hbridge takes 4 digital ports. The speed of the hbridge takes 2 pwm ports. That means 6 ports in total. There’s no reason you can’t share the same ports for two hbridge unless you need them to have individual directions or speed

Nink · Answer

Hi @DJ Yeah I need 4 motors direction all controlled separate so I think I will follow your post on the other thread and go with an arduino for the # of ports and usb control.