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I had 8 small and really old servos, as well as an ESP32 that was soldered onto a copper stripboard. I therefore decided to make a walking quadruped that would have something sticky on it’s stomach, allowing it to pick things up secretly when it belly flopped, (Like a card).

Because I only had 8 servos I could not use the normal 3 servos per leg that quadrupeds and hexapods use, I would be stuck using only 2 per leg. This combined with quadrupeds having a much harder time balancing than hexapods due to the gait, meant that it was destined to be slow from the start. (On the flipside, no-one ever expects a tortoise to run off with their credit card, so it always gets away).

In addition, most ESP32s have wifi, so we can control the bot from a PC. A lithium ion battery is best to power the ESP32 for this use because it won’t be limited by the range of a cable. I was planning on using a 3.7V lithium ion battery combined with a boost converter, however the converter I had was not operational. I was therefore forced to use a cable to power the ESP32.

I contolled it by running a webserver on the ESP32, then sending instructions from a PC using Python. The project was a weekend project, so some bits are rushed and could be optimised.

8 small servos, I used TGY-90s, these are old and were bought in 2014
ESP32 devkitC (Must have wifi), mine was soldered onto a copper stripboard before I got it.
4 AA batteries or a lithium ion battery with a buck/boost converter for the servos
Either a lithium ion battery with converter, 4 AAs, or a cable to power the ESP32
2x8pin and 2x6 pin headers
Lots of small screws, I used 7mm long and 1.45mm diameter screws. In hindsight these were too thin and had a tendancy for the head to snap off.
A sticky thing to go on the bottom, I just used 3M brown packaging tape folded on itself.
Double sided tape
Normal tape
Hot glue/ Super glue
Thin grippy rubber
Lots of small wires
Lots of zip ties
A switch
A 3D printer, or access to one
Paper to make the shell”

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