Powering Servo Motor via breadboard to myRIO

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Hi,
I am working on a uni project which involves controlling a SG5010 TowerPro Servo Motor using myRIO and LabVIEW. I have created a LabVIEW VI which can control a SG92R Micro Servo over a pulse width of 0.5ms-2.5ms with 50Hz frequency with no issues.

I purchased the SG5010 servo as I need a stronger motor for this project, but when when I run the code it makes a ticking noise and doesn’t move consistently. The motor is connected to the +5V power output pin on the myRIO which has a maximum current current draw of 100mA. It seems that this +5V pin doesn’t supply enough current to power the SG5010 servo, but could be fixed with an external power source connected via a breadboard.

What type of power supply (voltage/current) can be used to control the SG5010 servo motor? I heard that servo motors can be powered using 4xAA batteries or a LiPo battery but I am not sure what current is required and what the best rechargeable or wall outlet option is.

Any help would be greatly appreciated, thanks!

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Hi Kate,

I think you’re on the money there! A guide that uses that servo specifies it’s current reaching up to 300mA during motion, or up to 600mA at stall, so a beefier power supply may just solve your problems.

Usually you want your motors on a separate power supply anyway, as voltage dips can make a microprocessor seriously unreliable.

We’ve got quite a few supplies in our store, so if you let us know what the rest of your equipment setup looks like (breadboards?) we can suggest something easy and beefy enough.

-James

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Hi James,

Thanks for the reply!. That definitely makes sense if the motor requires up to 300mA during motion!

This is what the equipment set up looks like:

Set up
Set up1920×1440 234 KB

This is for a myoelectric claw project so other components will be attached to the breadboard, but only the servo requires a power supply. I assume something could be added directly to the board?

Let me know what you think, thanks!

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Hi Kate,

Unfortunately, you can’t just connect everything together and have it work (or work long-term), you’ll need to use an Optoisolator (sometimes called optocoupler) to convey the signal to the servo without back-powering the controller, or creating a ground loop where your power supplies are effectively fighting each other.

This breakout should be pretty easy to use, it has two channels so you could even use it with 2 servos down the line if you decided you needed to:

As for your power supply, a plug pack with a barrel jack at the end is all you need, you can plug them into a breadboard easily with one of these:

A suitable 5V supply would be something like this:

All the best with your project, and let us know if you need more info!
-James

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Thanks James, that helps so much.

Is the opto-isolator breakout needed due to the high output current (2A) from the DC barrel adaptor which can interfere with the myRIO device?

Could I use something like this breadboard attachment and eliminate the need for an opto-isolator as the output current is only 500mA (enough to move servo?):

I found this video of servo control with power supply and Arduino (similar to myRIO I assume), where they just used the breadboard attachment so would be interested to hear what you think:

Sorry about the questions, I’ve never used an opto-isolator before and can’t find much information online so am not really sure how they work!

Thanks again!

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Hey Kate,

Seems my understanding of ground loops and isolation was a little off, I’m going to do some reading and get back to you with a verdict!

(Maybe someone with a better understanding than me can pipe up)
-James

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