Behavioral Logic

Fetchbot Hardware

I primarily work in theory and software development, so when I wanted to test my theories in an implementation of robot software, I became severely out of my comfort zone. I was hoping that I could purchase a simple rover bot with motors and a camera programmable in my choice of platform (and in a hobbyist price range.)

Most robot kits are meant for hardware experimentation, but I wanted a stable and simple set of components so I could focus on software. Many of the ready-made robots can only be programmed in a proprietary language—often a "kids" development platform where you drag blocks around. This is completely inappropriate for exploring advanced AI. I also found the other extreme: robots meant to be programmed in C. It's a great language for embedded development like writing hardware drivers, but I needed a very high level language for natively manipulating complex data structures. (I had been exploring proof of concepts in Python, Node.js, and Erlang.) These are the reasons I grudgingly decided that I had to build my own Fetchbot

When I am confident in a stable kit of hardware, I'd love to share it with other robot programmers who are in a similar situation. I'll publish a comprehensive parts list and instructions, and I am considering compiling a crowd-funded kit so you can order everything in one box, including an SD card with core software and tools already installed.


State of the Hardware - August 2018

Version 2 of Fetchbot has been stalled for a while due to an issue with my chosen motor driver (I think.) 4 alkaline cells are not sufficient to power the motors of the Runt Rover. However, when I increase the power to 6 cells, the motor controller stops working. I am doing some troubleshooting to try and fix this as soon as I can, but I am not experienced at this sort of thing.

Fetchbot 2 Parts


Total Cost

About $95.00


With batteries, jumpers, and other parts you should plan on spending about $100.00 on this project, not including necessary tools like screwdrivers, a computer, and for setting up the Pi Zero: a keyboard, mouse or touchpad, HDMI monitor, and mini HDMI cable or adapter.

Fetchbot 1 Parts


Total Cost

About $120.00


For working with the Raspberry Pi


This was my first attempt at building my own robot and it worked, but I spent more money than I wanted. I think the cost could be brought down with a less expensive single-board computer (maybe a Raspberry Pi Zero) and USB camera.

The Actobitty has 2 rear wheels and a single front plastic runner so it is only capable of movement on a smooth, flat surface.

Assembly of the robot hardware is easy - a 12 year old should be able to handle it. Working with the Raspberry Pi is harder. Make sure you have the tools and experience needed for a Pi before you start.