Versatile Educational 2WD Robot

Description

The goal of this project is to provide a very affordable and customizable robotic kit, that can be 3D printed relatively quickly, and has a minimalistic design with the least possible amount of parts, but that is capable of perform several tasks, as line follower, obstacle avoidance, sumo fighting, etc.

Details

I had the following criteria in mind to coose the components of the robot and to design the chassis that would hold them in place forming the robot:

Economy
Ease of assembly/use
Versatility (different behaviours)
Adaptability to various coices of electronics and batteries
Easy to print
Parts easy to source
Compact form factor

With this as guidance, the firs important decision was to choose among various alternatives for the motors: DC geared micro metal motors, 5v geared steppers, or 360º servos.

The DC motors and the steppers would mean to include aditional electronics. So I choose 360º micro servos, prioritizing the simplicity of the assembly over, for example, the accuracy of movements of the steppers or the strength of the geared DC motors.

Files

connections_schematic.pdf

Preliminar connection schematic, might change.

Adobe Portable Document Format - 177.38 kB - 07/23/2017 at 15:01

Preview

avoid_bumps.zip

Arduino code of the "avoid bums" behavior test.

Zip Archive - 844.00 bytes - 07/23/2017 at 14:47

Download

printed_parts_stl.zip

All the 3d printed parts necessary for the robot, ready to be sliced and printed in a 145x135mm area.

Zip Archive - 393.64 kB - 07/22/2017 at 11:06

Download

LICENSE.TXT

The TAPR Open Hardware License

plain - 13.61 kB - 07/19/2017 at 15:41

Download

Components

2 × Continuous rotation micro servo A micro-sized hobby servo motor that has 360º rotation instead of 0º-180º

1 × Batteries A power bank or battery holder whose size does not exceed 105x60x25mm

1 × Development board The chassis is designed to carry an Arduino Uno form factor board.

1 × Marble A 16mm diameter marble is the cheapest and most available carter wheel

2 × Mini micro switch LxWxH Size:12.8x5.8x6.5mm,ON-ON 3P, Lever long 13mm

Project Logs

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Reinforcing the hinges
Dasaki • 07/24/2017 at 07:49 • 0 comments

Yesterday the new half mounted version of the rbot fell down the desk and one of the bumpers higes broke.
So I did some reinforcement in the design. The top image is the old version and the bottom image is the new version:
Avoiding bumps
Dasaki • 07/23/2017 at 14:58 • 0 comments

Quick video showing one of the simplest behaviors: the robot reacts to bumps detected with the microswitches, and changes trajectory accordingly to avoid the obstacle:
I used the previous chassis version (old parts printed in white PLA, one of the new version wheels in gray), before I mount everything on the improved chassis (shown in other logs, in yellow PLA)
Screwless (snap-in) servo mount
Dasaki • 07/22/2017 at 10:51 • 2 comments

One of the goal of the design is to reduce the amount of "vitamins" or buyed parts as much as possible, and at the same time to simplify the assembly.
So I modified the main chassis piece some to allow to snap in the wheel's servo motors, hoping they would hold in place firmly. The results are great, four less screws and motors quickly intalled.
Testing the bump sensors
Dasaki • 07/22/2017 at 10:08 • 0 comments

I've made a quick video showing the microswitches working with the arduino's internall pullups enabled, so you spare an external resistor:
Improving the wheels
Dasaki • 07/20/2017 at 11:26 • 0 comments

For better assembly of the rubber band (after noticing the inconvenience of having to remove the wheel to replace the band), I've redesigned the wheels so that the band is easier to put/remove.
Watch this video to learn how to put the rubber bands on the wheels:

View all 5 project logs

Discussions

Versatile Educational 2WD Robot

Description

Details