Building a 4 motor vehicle, having issues with H-bridge

Other Hardware Motors, Mechanics, Power and CNC
1

I have this set up,


aluminiumhydroxide

It is my first time wiring an H-bridge this way. I usually run it off 5V not 12V+.

This issue I am having is this...

I am powering the H-bridge with 12V (VMS pin) and using it's 5V output to power Arduino and all the other components.


images upload free

I upload a simple code to Arduino to have the motors spin in a loop 2sec forward and 2 sec backward, but the H bridge is not making the change between those. It only goes forward. If I disconnect the power to the H-bridge and connect it again, it pay go forward/back a few times but then it starts only going forward. I am actually using a velleman vma409 which shows which of the LN1,2,3,4 are in the "high" position. Instead of looping between LN1,3 ON, then LN2,4 ON, it goes LN1,3ON, then they all go on (1,2,3,4). Somehow having the 12V go into H bridge is giving me this issue. If I bring 5V to the H-bridge from the Arduino Mega, then the problem is fixed.

Also, I noticed that is i give the car some resistance to move forward, it will loop correctly in the back position, but if I don't touch it, the L1,2,3,4 lights go on which means all the IN1,2,3,4 pins are on high. Very weird stuff.

Any idea what's causing this?

2

Hi,
Where is the gnd link between your MEGA and the motor control board?

Can you post a link to spec/data of your boards please?

Tom... :slight_smile:

3

I think the H-bridge is broken. If I connect 5V to the H-bridge then everything works fine. Then the H-bridge output powers the mega and everything is ok. But as soon as I put it in the VMS, which is rated for high voltage then it doesn't work and it acts up.

Could it be anything besides the H-bridge? VMS is rated for 5-35 VDC (Volts Direct Current)

4

That board has a 5V regulator top left - it ought to work from just the 12V supply with appropriate
jumper settings. You should not be trying to run this H-bridge without VMS, the 5V rail is definitely
not designed to power a motor.

Your actual problem could be EMI related, or an inadequate 12V power supply, or something else,
its time to actually measure the supply voltages and find out what's actually happening.