Call for reviewers OWI-535 Robotic Arm Edge

Update 12th November 2015:

Hi all! We have the winner for this review: TitiMoby. You will be contacted shortly.
For all the rest please keep trying as any of you can be the next one. Good luck!

Update 4th November 2015:

Hi! Thank you all you who answered for being interested to review. Next week this call for reviewers will be closed. Stay tunned!



Hi dear LMR members!

It is always hard to create your first robot arm, but now you can get one in a kit for free! Keep reading!

Today we have the chance to get for free one nice OWI-535 Robotic Arm Edge by Owi for your review. It’s good to start in robotics specially for children: a robot that actually moves like a robot, easy to assemble and handle.

Its main features are:


  • 2nd Generation OWI Robot Arm trainer

  • 100g lifting capacity!

  • Wired control of gripper, wrist, elbow, base rotation and gripper LED

  • Quick to assemble and requires no soldering

  • Ages 13 and up


If you want to get a chance just tell in a comment:

  1. That you are a member for at least 1 month, with at least 1 publications of enough quality (it is at the discretion of LMR to decide that quality, but they are fair, just try your best!).

  2. What would you like to do with this OWI-535 Robotic Arm Edge.

  3. It´s not compulsory, but at least that you will consider the “Tips on writing reviews at Let’s Make Robots”, specially videos with LMR intro and end.

Between all contestants LMR will select 1 member who will receive for free and review this robot. Good luck!


Hello all!1. I want to be a

Hello all!

1. I want to be a reviewer but the only problem I have is that I have been only a member on LMR for 2 weeks. But I have done 3 publications (robots) on LMR and I think they’re of good quality :slight_smile: Just check out my profile under robots. I don’t know if my 3 publications can help me a little to qualify or not. 

2. I don’t actually have a plan but I was thinking of somehow, someway, to use it to pick up small bearings and maybe place them in columns. Or something that has to do with sorting/picking small objects. But I am not sure yet on how this robot is running and it there is some way to progam procedures into it. But I will try to figure that out along the way. And it could help me learn more about robotics :slight_smile:

3. I will ceratinly use the tips on how to write reviews on LMR and I will incorporate the intro and end of LMR of any video made for the review.

I hope to be considered. Thanks for your time for reading this!

That will be a perfect fit

That will be a perfect fit for the collaborative videos I want to make with my son (near 13)

We’ve already done some projects together like a robot here : TomTom robot

or some minecraft computercraft tutorial on youtube.

As this year he first started to have ideas on a possible study field, this will be a good shot for both of us.

In case of review this arm, I think I’ll let him assemble the thing and explain what was hard or easy, then we will try to show some basic drums with it (my son is a young drummer)

If it’s not with this robotic arm, I’ll find another way to help him share his passion, and I will post here of course :wink:

already tried it

I successfully hacked it with Arduino. Disassembling it i found it has 5 DC motors rated for 3-6 volts, feeded at -/+3 volts by alcaline batteries. So just adding a L293 or L298 motor driver won’t work, bacause they have an high voltage drop. Dagu mini driver can drive fine any of these motors, because uses low forward drop diodes instead of a one-chip motor driver.Each motor takes about 200-300mA, so do not power the motors from the arduino.

The solution is to power the whole thing with 4nimh AA every two motors or a 2s lipo regulated at 5v, a quad motor driver shield and a last motor driver to drive the 5th motor.The light can be driven by a pin with a small resistor. The arms weight about 400g, so it needs a base better than the usual beginner rover.

That’s a very useful

That’s a very useful comment!

Even without this review thing, I was wondering if it could be hacked to go further.

So the main issue was to keep high enough voltage to the motors?

it could sure get hacked

Well there is a bit of theory behind. H-bridge chips are tipically not simmetrical, and have diodes to prevent current going back to the microcontroller or in the reverse direction, with a transistor which switches the direction of the current, forward and backward, with the default position being forward. Cheaply engineered drivers have a less voltage drop on the forward direction, than the reverse direction, so the motor was running fine forward, with only 0.1V less than provided by the battery, by only buzzing in reverse, because the transistor had a big overhead of 2.5V(which is negligible if you are driving 12v loads).
In better engineered motor drivers have voltage drops that are about the same in both directions.

It is also powered in the kit by bid D size alcalines, which are good for a toy, but don’t last much and are quite expensive, nimh and lipo are much better. With 5v it gets better(faster, more load), but over 6v there is a chance to burn the motors, i tried with 7volts and makes a bad smell.

The precision and repeatability aren’t great, steppers and servos do better.
A good hack would be to add some accellerometers or encoders to get feedback about the position.
The gears shouldn’t be moved by hand, so it isn’t trainable directly.

Nice! I’ll prepare my son

Nice! I’ll prepare my son with the idea that he will have to work on this :slight_smile:

**Congratulations! **

Good TitiMoby! Congratulations!

We all look forward for your review and feedback from your soon :wink:

we are waiting for the

we are waiting for the arm.

but to be honest, today we talked a lot on other sad topics with the kids.

I just received the

I just received the package.

I don’t know if I will have enough time this week, but at least unboxing is coming

Glad to hear you received

Glad to hear you received the product. Looking forward to your review.