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Asked — Edited

Question For DJ About New H Bridge

Hi there, so i have managed to get a BV4113 H Bridge, i have installed latest firware and connected as per your diagram on the tutorials page, i have a pretty significant issue however, i have opened up a new project and i only have the BV4113 Movement Panel active, i connect to the bot fine but the issue is that if i now press one of the movement buttons nothing happens at all, however if i disconnect the BV4113 from the EZb and then reconnect it it works perfect, even if i disconnect and reconnect to the ezb via bluetooth its fine until i turn of the ez b, when i power back on same issue no movement, until i disconnect the BV4113 and reconnect it, then its fine again, its like this every time, it is as if the BV4113 requires a reset or resync b4 it will work, this is ok when my bot is opened up but when everythings inside i cant get to the board to unplug it and plug it back in again, any ideas ?

Thanks Kurt (NB i have double triple checked my connections, i have even tried toggling D0 on and off but even that doesnt work, i have to manually disconnect it then reconnect and its ok)

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Interesting! I'll take a look and see if I can think of something. Hmmmmmm!

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That would be great if you can DJ its a bit confusing i know, maybe something at firmware level would be needed to send a restart to the port on power up or to toggle power on and on, but im just guessing lol any ideas or help is appreciated :-)

Regards Kurt


I have the same issue- in fact, I thought the new motor controller was defective until I found this post.

Pacomms- what pins, and in that order, are you disconnecting/reconnecting between the EZ-B and the H-Bridge to trigger operation? I am trying to recreate your problem/solution, but so far I can only force the motor controller into operation by bouncing the Bluetooth connection between the host and the EZ-B.


Interesting. When the EZ-B powers up, the bit of voltage (noise) on the digital i/o line confuses the UART of the BV. I'm looking into what I can do about that.

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I basically just pull the servo lead off the ez b and reconnect, sometimes it takes more than one attempt and also when the board does come back online you may need to press say forward twice, after that it works fine, noise over the pin does sound like the issue DJ, not sure how to fix that though, short of maybe a resistor ?

Thanks Kurt


The pressing twice is expected. It requires an init on first use. That's something we can all live with. However, the other issue is strange. I experience it also.

To resolve it..

  1. power ez-b

  2. unplug motor controller from ez-b (the digital i/o plug)

  3. plug motor controller back into ez-b

  4. it works

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Thats the same as what i have to do ? however if that connection is inside the bot then its gonna be a bit of an issue, i think i may stick with the sabertooth for now, my only issue is that with the sabertooth i cant use the ping scan unit, because i have to create a script to turn etc etc, and the ping sonar scanner uses a movement panel, which of course i dont have because there isnt one for the sabertooth. I wonder DJ is there any way of including a Movement Panel for generic use that follows whatever is set in the movement script panel, then i feel that people could use any motor controller and the other utilities that dont at present, just a thought



ould you use a relay with an nornally closed connection to toggle the hbridge off and on?


@pacomms you technically can add a modified servo panel, set the ports to NA and use the script panel. The problem is with the script execution time is slower than the MS response time needed for a Movement Panel reaction.

I emailed Sabertooth, they were not willing to donate a board for development. I don't support products that don't support EZ-Robot.

As for the Sabertooth, if it doesn't like the pulse width of a modified servo panel to be in R/C mode, then try something for me.

  1. Connect your sabertooth module in R/C mode.

  2. Add 2 standard vertical servo controls (one or each motor)

  3. Set the vertical servo controls to the ports the sabertooth is connected to

  4. Slide the dials and tell me what the maximum and min values are of when the motors move.

Maybe i'll consider adding support for the sabertooth pulse width when i have time.


So is there likely to be a solution to the new H Bridge situation beyond needing to unplug the connection every time? I have one on order but that solution won't work for what I've got planned.

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Hi DJ thanks for the response, so i have done what you said and the results are as follows, setting the slider at 35 stops the motors, setting to 51 gives full power forwards and setting to 20 gives full reverse. as for just starting to move in the forward direction it just starts moving at 44, and reverse is 27. I understand regarding sabertooth, they are hard to deal with, i emailed them twice and got 1 canned response saying that the micro controller must be putting out incorrect pulse widths which i know is rubbish, end user support from them is nil to be honest which is a shame as it is a good solid product to be honest i have used it in a few projects, its just the Movement Panel issue is all, without a Movement Panel that doesnt need scripts etc etc i cant use the sweeping sonar module, nor the colour tracking proper, small issue i know but hey ho i just like everything to work ;-), if you could maybe put a panel in for it i would be eternally grateful and i will come round and do your housework for a month, well if i lived in canada i would anyways lol

Regards Kurt


I'll modify the modified servo Movement Panel to allow specifying values for the controller.

It'll be in the next release. your sabertooth will work flawlessly with the modified servo movement panel

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Thats Perfect DJ that will be great :-)

Thanks Kurt


Has there been any movement on this issue? I got the motor controller to work a couple of times, after extensive connecting/disconnecting- but now it won't do anything.


Yup - it's in the works, of course - think i'd forget?:)

As for work-around. After the ez-b has been powered up, simply disconnect and reconnect the servo plug to the ez-b. I have 100% success with that while testing to find the issue.


Happy to report that I just upgraded to 2012.01.01.00 and the new H-Bridge works without needing to be unplugged every time! Thanks, DJ!


Could someone provide a link where the BV4113 is sold.




Click on "Choose Items Individually" just under the "BUY" tab. The H Bridge is near the bottom of the list described as "1.5 Amp Motor Controller".


Quick question: in the BV4113 control panel, there's a slider on the right. I'm assuming this is for speed control but the speed doesn't seem to be changing when I slide it up and down. The small DC motors that the HBridge is controlling has capacitors across the terminals. Could this be the problem or is this slider for future functionality?


Ah, the slider is for future functionality. I had some heat issues with it. It's on the list, just further down:)


dj i have 3 of the sabertooth 2x25's. i'm using 2 of them right now. i'm tempted to send you one of them to test, then you can send it back when you are done. they cost me $130 usd each but i trust you.

i'm going to try to unplug trick and see if that works.

do you think maybe the pwm signal is correct but maybe its picky on the voltage?