Asked — Edited
Resolved Resolved by Rich!

Need Help On H-Bridge.

Has anyone worked with the Soduino?

Specs 60A SX7970 Made by:

as you can see in the picture, it has in1,in2,in3,in4, just like the other popular hbridges.

Now, i don't know what the en_L and the en_right is for (i will guess encoders which I won't have on my robot for now.

+5V and Ground are self explanatory.

The problem is when I get the unit in, it has all together different labels and instead of having one horizontal row of 8 pins, it has two rows of 4 pins.

The labels are as follows:

  1. R_PWR
  2. L_PWR

3 R_EN (assuming this is encoder but not sure.) 4. L_EN (Where should I hook it?, What pin does it line up with?) 5. R_IS (Have NO idea what this means or Where it should hook up.) 6. L_IS (Have NO idea what this means or Where it should hook up.) 7. VCC +5V 8. Ground

How do all of these pins line up with in1,in2,in3, in4 and EN_L EN_R.

Is seems that the other h-bridges that I used I only used 1234 and +5v and ground for the logic control.

It looks like it's time to ask an Engineer. I am in the dark. Please help me on this.

Thanks, Mel User-inserted image

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En usually means enable. These will be used for PWM for speed control if it's anything like the L298n.

I'll see if I can grab a datasheet and have a read over it and confirm all pin connections needed.

Saying that, it has PWM inputs anyway so may be different... IS I have seen somewhere, possibly the Dagu controller... I would guess it is a current monitor which can connect to ADC to let you know how much current is being drawn by the motor.

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OK so all I can find is one that looks like this... User-inserted image

Different pin names, different board... The above seems to match your description but not your picture. Which do you have? The one you showed is not the one you said it is.

Do you have a datasheet with it?

Do you know if a datasheet that isn't in Chinese exists?


Right! that's what it looks like.

The reason I bought this one because it was $45 as apposed to $300 that I could not afford. This is the controller for my wheelchair. I completely disassembled the Sunshine robot and I am going to rebuild her. Hopefully!

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From the limited information I have seen on the board it is for a single motor not two motors. Hence the lack of 2 connections for motors...

B- & B+ are battery in for the motor supply. M- & M+ are the connections to the single motor.

On the other side of the board we have the 4x2 header. This is where even I get confused since it's a single motor output but you have L and R pins.

VCC is likely to be your +5V from your controller GND is your ground

The rest is unclear and with no datasheet it will be a huge amount of guess work.

Please don't take offence but I would be reluctant to tell you what to try in which order based on some of your posts regarding incorrectly connecting things up.

Some H-Bridges (L298n etc) use In1 & In2 to tell the direction to move, to apply a brake or to freewheel. I.E. if both are high on the L298n it applies a brake, if both low it freewheels, if 1 is high and 2 is low it spins in one direction, if 2 is high and 1 is low it spins the other way. Then the ENa and ENb are used for speed control with PWM.

Other H-Bridges use a different method. The Dagu for instance has current and direction. If current is high it says "Ok, let's go" and then checks the high/low of the direction pin for forward or reverse, while the third pin alters the speed based on the PWM.

I'll have a bit of a better look now I know what it is I'm looking for however, if you got this to drive 2 motors I believe you will be disappointed.

A side note: You get what you pay for. If you want to run high current draw motors you will need a sabertooth or similar. I know the cost is high but they will work without a single problem.

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Ah ha!.. Perseverance and thou shalt succeed...


The control method Method 1: VCC by single chip microcomputer of 5 v power supply, GND MCU GND. R_EN and L_EN connect 5 v high level, drive into the working state. LPWM input PWM signal, RPWM to low level or impending, motor is turned. RPWM input PWM signal, LPWM to low level or impending, motor reversal. Method 2: VCC by single chip microcomputer of 5 v power supply, GND MCU GND. With L_EN R_EN together and input PWM signal's speed. High level LPWM input, RPWM input low level or impending, motor is turned. High level RPWM input, LPWM input low level or impending, motor reversal.

Obviously a poor translation.

VCC is +5v from the EZ-B GND is ground Tie L_EN and R_EN together and put to a digital pin. i.e. D17 LPWM to another digital pin. i.e D18 RPWM to another digital pin. i.e. D19

To enable movement first set D17 high. Then for direction... For forwards set D18 high and D19 low For reverse set D18 low and D19 high

Speed control looks like it may be done by using PWM on D18 and D19.

L_IS and R_IS are current monitoring pins. Connect these to ADC ports for current monitoring. Before you do, check the voltage with a multimeter to ensure that it will never go above +5v. According to what I read I = 19.5 x UIS, so current will be 19.5 x the voltage on L_IS or R_IS (as applicable).


Hey Mel...Why not just use the sabertooth 2x25 which will work fine for your wheel chair base.... it only cost $124 and it is the easiest and in my opinion the best controller in the world to use.... Not sure where you were shopping to need a $300 controller.... And no offense, but you always claim you are so poor but yet in the last little while I believe you bought the wheel chair base and a 3d printer... ! As Rich says, if this H_bridge turns out to have only a single motor channel (which is looking to be the case), you won't be able to use it as planned... Don't cheap out anymore, get the Sabertooth...;)


the wheel chair was a gift to me. It had the top part broken. Remember, I live in an old folks home. I considered the sabertooth, but I was told that I would need a 60A. This one is supposed to go upto 70A. I cannot afford the sabertooth. sorry.

This controller is supposed to be a dual motor controller. When I saw the first picture you see displayed, it had the same type of connections ; ie; as the sabertooth. I figured it was just a chinese copy of the sabertooth. I bought the 3D printer by going to the loan company and hocking my car. I had the fever for that printer and I have enjoyed it.

sorry if this frustrated you. I have got to stop doing that.

Here is the link. I believe the price is now $20+ but, I paid $39.99 link

Thank You Both for your help and advice.


Mel, I am not dissing you at all... Tying to save you frustration, time and money.... Listen, you do not need the 2x60 controller.... Whoever told you that is plain wrong. I am willing to bet even the 2 x12 would work just fine as well.... Go to dimension engineering's web site and see for yourself... the 2x25 can handle robots of up to 300lbs...and peak amps greater than 50... Also, those motors will be lucky if the draw 5amps (locked) each... that still gives you 20amps per channel breathing room... By the way, if are still worried about it just put a 20 or 30amp fuse on the positive side of the battery... if the chair pulls too many amps (which guaranteed won't happen) it will just blow the fuse protecting everything else...

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I sort of agree with Richard, in the fact that you shouldn't go cheap.

Personal experience over the past 2 years has shown me that buying cheap, buying chinese replicas, etc. has cost me more in the long run than if I had gone and got the right thing for the job with the correct, clear instructions.

The H-Bridge you have got here is a "Dual BTS7970" based H-Bridge however it will only control a single motor. The dual BTS7970 doesn't mean it is two channel. The tell tale sign it's for a single motor is that it only has one motor output on it.

So with that in mind, you spent $40 for 1 motor when you need to control 2 motors. Total would be $80. A better, well documented motor driver is available for just a little more.

Sure, we managed to figure out how to wire it this time but that's not always the case. This one was one of the more difficult to find information on since everything was in Chinese and was image based rather than text based which meant it couldn't even be run through google translate.

The datasheet on the BTS7970 chip is here if you need it or for anyone interested in it.

Do your research, ask on here for advice and opinions for things you are not 100% sure on before laying out any money, you'll find you get a lot less problems:)

With regards to the current the motors will pull, have you measured this? A multimeter is your best friend and for a few bucks you can pick one up. Measure the current draw from the motors and use actual readings along with datasheets to help you decide on controllers and drivers.


Thanks Dual Rich Bridge. I will have to do this over since it is only one motor. Blah!

ok, I'm over it.




@richard r,

Where is the link for $124? on the 2X25?


I show it at @280 plus SHH


The shipping alone is $117!

where is it for $124?

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Sabertooth 2x25

Why buy a possible counterfeit board from a seller in hong kong through ebay? Ebay is one of the worst places to buy from at times, this seems to be one of those times.


@Richard R,

I am on a tight budget. I live on SSI at $721 per month. I used to make good money, but not now.

I have in fact ordered the one you suggested. Lucky for me, I have a birthday in June. I was going to get the Simplify3D software, but I guess I need this more.

Now, I could use help, I would like to know how to set the switches. I want to run it on 12v instead of 24 so it won't go so fast. I have two batteries so hooking them in PAR should get a lot of time. I would like to be able to control with the little windows on the screen that lets me go in any direction plus have a power control on it. Also, I would like to give it commands from the command script console and run things like navigation.

I plan to have two EZB3s and one EZB4.

It will look like Lexi but in a spastic sort of way. I will have much weaker arms.

Thanks to both of you for the help.


DJ has already done the work for you on the sabertooth.... Sabertooth setup

Being on a fixed income is exactly my point of why it is so important not to buy cheap... You don't have money to throw around, so make sure your purchases count... buying cheap usually means buying twice... costing more in the long run... LEDs or toggle switches, etc... little things like that, then eBay is your friend for sure....


OK, then, I am all set. Just waiting for the sabertooth to come in. I forgot about Roboshop which I have purchased from many times. I bought from the factory.

Thanks again for all of the help!


One more caveat... make sure you wire the battery correctly ...with all it's virtues the sabertooth (2x5 anyway) does not have reverse polarity protection built in.... I have a charbroiled black coloured one in the corner to prove it.... Talk about a waste of money... I lost $69 in a few seconds on that brilliant move...:)



I hope you didn't cancel your order based on my last post. I miss read thinking you were looking for a 12 amp ST. Please disregarded.


Hey Dave, did you also say you had a 2 x12 for sale as well? Not sure if this or the 2x12 that was what you offered Rich... anyway, I was going to buy myself another 2 x12, so if have one to sell, I am interested...


Thanks Richard, I hope I didn't cause Mel any trouble by offering him something that wouldn't work. I see now you guys were coaching him towards the 25 amp model ST. If he only needs the 12 amp model that is what I have and I'm still willing to sell him the one I have available. It's the only one I'm willing to let go at this time.


No worries Dave... He has wheel chair motors.... the 2x12 would probably still work if he takes it easy and the bot is light, but I would still recommend the 2x25 for those size motors... the 2 x 12 might get a little annoying by shutting down on him occasionally if too much current is asked of it...


Thanks, Dave. I have already ordered and have solved the problem. But, I did not even see your post. It must've not been on this thread.