NEA-TTO | HP Robots | Otto Sweeping Robot

+++ I'm currently looking for betatesters for this model! If you own an Otto kit and want to help please let me know. I'll give away free FlexiDinos models to all the betatesters, just reach out if you're interested. +++

This is my entry for the Printables HP Robots Otto: Remix Challenge. Since I do not own an Otto kit to test it, it's more of a concept than a fully fledged design, but I hope to reach top three in the contest and win a kit to be able to continue working on it. So far everything twists  and turns as it's supposed to do, but I don't know if the motors have the power to drive it.

There will be some updates until the deadline of the contest, I just wanted to publish it and work in the feedback from people who try it out.

Introduction

When I was a kid I wanted to become a robot, when I grew up. I was very disappointed when my mum told me that this was impossible. So when 30 years later a vacuum robot became available at the local discount store I was very eager to get it. I didn't clean the floor for a month in advance to give it a challenge (actually I was just a lazy slob and it gave me an excuse not to, but it sounds much better that way).

If somebody told me then, that it will become achievable to design my own vacuum robot, I wouldn't have deemed that possible. But here we are now.

Print instructions and assembly

BOM

• PLA

• TPU

• 4 × M3 nuts

• 4 × M3 × 12 screws (can be longer)

• matching screwdriver bit

• knife for detaching the brush bristles

Step by step assembly

1. Print the PLA parts

2. Print the TPU parts

3. Attach the rear, geared, motorized wheels

4. Insert the 4 nuts in the outer shovel

5. Insert screws in the nuts from behind, don't tighten them yet, they act as tensioners for the belts later on

   

6. Insert the inner shovel into the outer shovel

7. Attach the assembled shovel to the holes in the Otto bottom part

   

8. Insert the small TPU spokes in the PLA gears. The tips of the spokes should face the short edges of the gears

   

9. Put the gears in the TPU roller, mind their orientation. The wheels should be able to move freely in the reverse direction. 

10. Put the roller in the shovel

11. Put the tracks over the wheels

    

12. Alternately twist in the screws to tension the belts. BE CAREFUL AS THIS COULD DAMAGE YOUR MOTORS!

    

Design 

As I have to work without being able to test my ideas on a motorized version of Otto, I decided to take a mainly mechanical approach and save the electronics for later. This means to use the existing parts of the basic model.

I wanted the already existing wheels to drive an additional brush in front of the robot. This means that the wheels are connected by a rigid joint, and I need to find a way to allow them to rotate independently. This resulted in three parts to get this done.

Belts

To apply the torque from the wheels to the roller I took inspiration from Alex Just Alex take on the tracks. 

Roller / Brush

This needs to have two separate wheels with one way only drives as it is the connection between the two drive wheels attached to the motors. I chose to have a print in place solution here at first but then came to the conclusion that the spurs need to be printed from a flexible material for durability.

I'll focus on getting the whole construction to the inside of the roller instead of attaching it to its sides over the next days, so this is not the final version yet.

There will also be a brush and a squeegee version, I'll add the brush in the end, as it takes up a lot of processing power to render all the bristles which makes it impossible to further work with.

Bearing / Shovel

originally these were two separate parts but I came to the conclusion it would be more elegant to combine them into one. This serves as a belt tensioning mechanism and a way to collect the cleaned up particles. 

Future add ons and modifications

1. Brush variation of the roller

2. Hide gear mechanic inside of the roller (this gives me much more space to work with and is a more elegant solution) ✅ 24. 3. 2026

3. Backpack and turbine for actual dust collection. The goal is to have an actual vacuum robot. Gemini came up with the RS-390 vacuum turbine. As I don't have any experience with electronics yet but achieved some astonishing results in BEAM robotics with Gemini's assistance I'm confident this will work. So I'll add a backpack to collect the dust attach it to the shovel and insert the turbine. It'll be so easy. /s

4. Programming NEA-TTO (If I manage to win a kit)

Edit, 24. 3. 2026:

• Replaced TPU and PLA parts file, switched out the front wheel with a modification that has the one way mechanics on its inside.

• Replaced the roller with a version with higher tolerances

Edit, 25. 3. 2026:

• Added photos for assembly and refined text

Disclaimer: This text was really typed by a human (me) but checked and corrected with the help of Deepl.com.