Simple Bots: Wobbler




About: My name is Randy and I am a Community Manager in these here parts. In a previous life I had founded and run the Instructables Design Studio (RIP) @ Autodesk's Pier 9 Technology Center. I'm also the author ...

Typically, you learn how to wobble before you learn how to walk. But in the world of bots, anything is possible! That is why a day after showing you how to walk and two after showing you how I roll, I am back to show you how to do a little wobble wobble. That's right! In almost no time, you can be out wobbling around with the best of 'em. All of the parts in this project are simple to find and even less-than-experienced bot builders should be able to make this one pretty easily. And, more experienced bot builders should be able to have some fun modding this one, as the casing leaves a lot of room for experimentation.

Want to watch me build this project from start to finish? Check out this webinar I led on June 13th 2017 to see me complete the whole build!

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Step 1: Go Get Stuff

You will need:

(x2) continuous rotation servo motors with the controller removed**
(x2) self-adhesive oval coat hooks
(x1) 4 x AA battery holder
(x4) AA batteries
(x1) small plastic container
(x4) zip ties

**To learn how to remove a servo controller, visit this page.

(Note that some of the links on this page are affiliate links. This does not change the price of any of the items for sale. However, I earn a small commission if you click on any of those links and buy anything. I reinvest this money into materials and tools for future projects. However, you are obviously free to source the items as you please.)

Step 2: Remove the Horns

Remove the servo horns from the motors.

(The servo horns are the gear-like objects attached to the motor shafts.)

Step 3: Insert

Place the servos inside the plastic container such that they are mirrored back to back. The servo shafts should be located near the bottom of the plastic container and off-center.

Step 4: Mark

Mark the plastic container with a dry erase marker to indicate the position of the motor shafts and the servo mounting holes.

Step 5: Drill

Drill holes in the plastic container where you have just made the dry eraser marks in the previous step.

For the smaller mounting holes, an 1/8" drill bit should be suitable. For the motor shaft, I recommend using either a 3/8" or 1/2" drill bit.

Step 6: Mount the Motors

Position the motors inside the case and zip tie them securely in place.

Step 7: Wire It Up

Twist together a red wire from one of the motors with a black wire from the other motor, and either wire from the battery holder.

Next, twist together the remaining three wires to form another pair.

You can solder them for a more permanent bond, if you wish.

Step 8: Close It Up

Place the battery holder inside the case.

Close the case and reattach the servo horns.

Step 9: Wheels

Take the coat hooks and trim off the hook part with diagonal cutting pliers or a small saw.

You should now be left with self-adhesive oval wheels.

Step 10: Attach Wheels

Peel off the adhesive backing and secure the wheels to the servo horn such that the horn is completely hidden behind the wheel and the wheel is very off-centered from the axis of rotation.

Step 11: Power It Up

Remove the lid, insert batteries, replace the lid and let it go.

Experiment with putting the bot on different sides to observe all of the ways it moves.

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20 Discussions


1 year ago

Great and simple, the good idea is to advance the bot as a swimmer on the ground,
maybe when I build it, I do an infrared or ultrasound to avoid obstacles, back, left, right
Thank you.


2 years ago

Thank you for putting the video first. Several times I have been interested by a title, but had to look for a while to see what the project was actually going to do. Your way is more efficient.


8 years ago on Introduction

Where do you get the self-adhesive oval coat hooks? I can't find anywhere in the US that sells them (Google shows them only in the UK). Any suggestions?

3 replies

Awesome project neat if i change the wheels to something that makes noise and hook up to a timer i will be awake on time
ur awesome


7 years ago on Introduction

Nice & innovative idea!Can you please tell me can we use toy motors instead of servos as they are expensive and wheels instead of coat hooks? Thank You!

1 reply

yes because the servos already have their *stuff* removed and act like normal motors that you would find in RC cars

rajat j

7 years ago on Introduction

hey can we use normal wheels in place of those self adhesive oval coat hooks as they r not available in india ??

1 reply

hey, randofo. can you please suggest a very easy yet innovative robot that a 13 year old like me, could build in 3 hours? since i really liked your projects, thought i could ask you to help me... i need to make it on the spot, so can't use anything like soldering,chips,servo motors,etc
Thanks a ton

rajat j

7 years ago on Introduction

hey can u please tell wether v can use normal wheels???


9 years ago on Introduction

Amusing! I had to laugh, even though I'm reading this from a Library. You need to figure out how to make it go in a relatively straight line. 8>)


Reply 9 years ago on Introduction

It has to do with the wheel positioning, one is slightly higher than the other one. I have re-adjusted them a few times and I could never seem to get it perfect, as it always drifted to one direction over the other. I figured that, perhaps, that is just what it wants to do.