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Asked — Edited

Strange Behavior With H-Bridge Widget

I got the omi-535 robotic arm wired up easily, first try, no soldering required.

The ARC setup was also cake.

There was one strange issue, movement control "up" and "down" directions seemed to be bleeding over into "left" a bit. When this occurred, the left / right motor was acting like the voltage was very low as it rumbled a lot and moved more slowly than the target up/down motor.

So to recap.. with the ez-buidler h-bridge control:
left - works
right - works
up - works (but does a little left)
down - works (but does a little left)

Using joystick buttons and script to control ez-b directly
left - works
right - works
up - works
down - works

Any ideas?


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#1  
It sounds like you have something connected incorrectly. Logic works with ON/OFF (1 or 0), so "bleeding" is not a term applicable to a digital circuit. Short would be the appropiate word.

Follow the HBridge tutorial and ensure you have everything connected correctly: http://www.ez-robot.com/Tutorials/Hardware.aspx?id=25

Because of what you described, it is not wired correctly.:)

As a recap, the Joystick (or any control) uses the Movement control. For example, when you say "the joystick works but the HBrdige control doesn't" - is invalid. The Joystick communicates with the HBridge control (or any Movement Panel that is added). It would be impossible for the joystick control to work, and the HBridge to not.

Check your wiring and i'm certain it'll be an easy fix once you notice it:)
#2  
The h-bridge is wired correctly.

On closer observation, it looks like ALL directions were running two motors because I had set the B triggers.


I think I'm just not understanding the software control config.

I get left a, left b, right a and right b, makes sense.

But why no up and down?
#3  
I think figured it out...

The only thing wrong was my understanding of the movement control

The control DOES send two signals at a time,
1) for forward it sends two forward commands
2) for backward, it sends two backward commands
3) for left it sends a forward and a backward
4) for right it sends a backward and a forward

I was so puzzled because it was moving two motors at a time.

So I wasn't crazy, the custom scripts (attached to joystick buttons) were moving one motor at a time while the joy stick motion was moving two.

Now I understand why there can only be one movement control, this control is very specialized for a certain kind of robot, the kind that DJ build a lot of.

Keep in mind, I am hooking ez-b up to an owi-arm so in my mind, "movement" meant.. well.. movement of the arm. I was treating the control like a joystick.

Is there a way I can watch what commands are being sent to the EZ-B? This would have been very helpful;)