StrandBeests are moving mechanical sculptures created by Theo Jansen with mesmerizing legs movements that organically flow with the wind. The beauty in their leg design and construction has inspired many to build robot walkers with similar gaits.
I've always wanted to build a Strandbeest robot, and after trying many projects on MakerWorld and Printables, I've come across two that I can recommend after building them with my kids. This post covers the first.
The first is a design by a Turkish maker Mert Kilic:
Instructables
Mert has many other easy-to-follow builds on his Instructables and YouTube channel, I recommend checking his portfolio out.
Our version of Mert's Octopod robot is named Spidey and it's fast.
This is our first robot with a "brain" powered by the ESP32. In making the robot, we had to learn how to use a breadboard and connect the wires in the right pattern to move the robot. We also learned about H-Bridges and motor drivers, though I don't think much of the H-bridges stuff stuck. The motor driver I used as a DRV8833. I used a USB power bank as the battery.
Using an ESP32 meant that we could control the robot via Bluetooth Low Energy using an iPhone. Phone control was a decision I reversed later on and swapped in an IR remote so the kids can play without taking my phone and snapping random pictures.
One downside to this robot is that often the legs would get stuck because the weight bearing down on the 3d-printed linkages. These incidences can be quickly resolved by quickly switching back and forth, but remain an annoyance if you want the bot to traverse large areas.
The kids got pretty rough with the robot and our breadboard circuit didn't last long. So I soldered a protoboard with an Arduino mini and motor driver and stuck it inside the robot. In this next iteration of the robot, I also added ultrasonic sensing and we talked about the basics of sonar and how animals used it to echolocate.
In this version, I replaced the phone app control with an IR remote so the kids can grab the robot and play at anytime without needing me to unlock the phone.
The ultrasonic sensor gives the robot an autonomous mode where it backs away from obstacles and turns to try to go around it. However, autonomous mode only lasts until the leg linkages start sticking.
All in all, a great starter project and very easy to put together for us. This won't be our last Strandbeest. We'll carry the concepts here to larger and smaller ones.