Power to the Hbridge

Drive a 4-wire bipolar stepper motor or a pair of DC motors from your Arduino. [Product page]
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micky
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Joined: Sat Jan 17, 2015 3:54 am

Power to the Hbridge

Post by micky » Sun Dec 27, 2015 9:46 am

Hi,

I have a Uno, and your Hbridge.

At the moment, I always disconnect the power to the Hbridge BEFORE I de-power the Uno, as I have read that leaving the Hbridge powered up with the Uno unpowered can cause major dramas to either the Uno and /or the Hbridge.

Is this correct, or can I de-power the Uno, then the Hbridge?

In your quick start guide, there is a photo showing 12v into the Uno's DC jack, and also, I assume, a USB cable into the Uno as well. I thought that the Uno only could be powered by either the USB OR the 12v jack, not both!

Ultimately, a USB cable will only be used to upload the sketch, so will the 12v input into the Uno's jack be enough to power both the UNO and the Hbridge and the motor?

Sorry to ask this question at this time of year, but I have patience.

Thanks

Mick

andrew
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Re: Power to the Hbridge

Post by andrew » Sun Dec 27, 2015 11:27 pm

You can remove power from either first, however it's easier to have one power source for both your Uno and the HBRIDGE shields.
The USB cable can be left in when uploading a new sketch, we must have done this during the original photo shoot.

Sure you can power both via the Uno's DC socket, or via the HBRIDGE with the "Bridge motor power to Vin" jumper on the shield. As long as you don't exceed 12V of course.
If you have any more questions let us know.

micky
Posts: 8
Joined: Sat Jan 17, 2015 3:54 am

Re: Power to the Hbridge

Post by micky » Mon Dec 28, 2015 12:04 am

Thank you Andrew

So to clarify it all in my brain, if I

1 ) power the Uno with a 9v battery to the Uno's jack

2 ) Remove the "Bridge motor power to Vin" jumper on the shield

3 ) In-put an 18v nimh rechargeable battery pack into the screw terminals on the shield to make sure that there is always at least 12v going to the motor and shield.

All will be good with the world.

At the moment I'm using a 12v adapter via the screw terminals on the shield, jumper removed, but as the shield, and the motor need a min of 12v, and typical 12v battery packs, tend to run from 12.6v down to 10.5v , I will probably run out of battery, hence the 18v pack.

Thanks

Mick

andrew
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Re: Power to the Hbridge

Post by andrew » Mon Dec 28, 2015 1:04 am

That's fine, as you're not connecting motor power to Vin.
You should use 4 x AA instead of a 9V to the Uno, as they will last a lot longer.
The average 9V battery is around 200 mAh, whereas 4 x AA should get you around 2000.

micky
Posts: 8
Joined: Sat Jan 17, 2015 3:54 am

Re: Power to the Hbridge

Post by micky » Mon Dec 28, 2015 2:34 am

Thank you Andrew, this info has solved the major issue!

I thought that the Uno needed between 7 & 12v to operate, if I can use 6v all the better. I will give it a try.

Mick

andrew
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Re: Power to the Hbridge

Post by andrew » Mon Dec 28, 2015 5:41 am

micky wrote:Thank you Andrew, this info has solved the major issue!

I thought that the Uno needed between 7 & 12v to operate, if I can use 6v all the better. I will give it a try.

Mick
Oops you're right - use 6 x AA not 4 x AA. I've been napping too much during the holiday :)

micky
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Joined: Sat Jan 17, 2015 3:54 am

Re: Power to the Hbridge

Post by micky » Mon Dec 28, 2015 9:16 am

Thanks

I went to sleep during the cricket too!!

Enjoy New Year.

Mick

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