PicoCat v2

All about PicoCat and the new upgrades and improvements

25 March 2022 by Kevin McAleer


Table of Contents


PicoCat Origins

PicoCat is a remix of Opencat, created by Dr. Rongzhong Li in his dorm room back in 2016. Rongzhong went on to create Bittle, Nybble and the company Petio.

PicoCat is different because its powered by the Raspberry Pi RP2040 chip, either in the Pico form or new Pimoroni Servo 2040 board.

What is PicoCat?

PicoCat is a 3d printable, opensource Cat robot, programmed using MicroPython.

Upgrades

Body

The first upgrade is the new body, which is designed to accomodate the Servo 2040 board, which is a tiny bit wider than the original body.

Servo 2040

The next upgrade is the Pimoroni Servo 2040 - a Raspberry Pi RP 2040 powered servo board, that can connect up to 18 servos, and a bunch of sensors to. Its the perfect size for PicoCat, and combines the MicroController with the Servo interface.

Previously I’d used a regular Raspberry Pi Pico, along with an PCA9685. The problem was that these PCA9685 boards can be a bit finicky, and it can require even more hardware to split the power between the Pico and the PCA9685.

MicroPython code

Next, I’ve revisited the MicroPython code, and simplified it somewhat. The RP2040 makes using the servos a lot easier, the servo movements to the correct angles are now much more acurate.


Electronics

PicoCat uses regular servos for each leg, foot, head, neck and tail. All 11 servos are the same type. You can use SG90s, MG90s or DS-929MG servos for the best quality.


3D Design & files

I created a couple of videos on how to design the PicoCat:

PicoCat & Fusion 360

PicoCat & Fusion 360 #2

PicoCat UnitTesting with MicroPython