All articles

  1. Catch up

    We've been rushing to get some hardware working in time for the deadline and neglecting the blog in the process. Due to one thing and another we've had less time to work on the robot than we'd hoped. Now with the delay of the official competition date we've got room …

  2. Motor Board Bring Up

    I've populated the critical parts of the motor driver board now. The connectors and pin headers can wait until I've verified the microcontroller is running.

    Motor driver PCB with the main components populated.
    Mostly just connectors to add, there are some missing ESD protection diodes which are on backorder

    The STM32G0 series microcontroller on our motor board is …

  3. Backwards LEDs Don't Work

    Good lesson today as I tested out the battery status LEDs on the side of our main controller board; the polarising mark on the WS2812B smart-LED isn't on pin 1, in fact it's opposite pin 1.

    I'd populated the board and had assumed the chamfered edge on the LEDs was …

  4. Power and Pi

    Having designed the motor controllers the last main chunk of electronics needed is the stuff that wraps around the RaspberryPi. We're planning on using a Pi4 for two reasons. One is that we hope to exploit its processing power with a camera to do some tasks autonomously (time will tell …

  5. Motor Control

    We've already discussed what motors we're using. These motors need some fairly hefty speed control, they have a stall current of 3.4A. They've also got magnetic encoders which means we need real-time encoder monitoring ability. Real-time stuff on the Pi is challenging, and monitoring 4 quadrature encoders with one …

  6. Batteries

    Picking a power source for the robot was the next big challenge. We need to run quite power hungry motors and we're planning on using a Pi4 so we need a decent battery capacity.

    A Bosch Power4All power tool battery.
    A Bosch Power4All battery pack, this is the 4Ah battery pack.

    The first idea that sprang …

  7. Motors

    Obviously we need motors for our robot. The easiest option is to buy motors with a reduction gearbox already attached. This will reduce the speed but increase the torque (how "strong" the motor is).

    Picture of a small yellow platic motor and gearbox common in toy robotics.
    One common and cheap option for motors, a bit small for my ambitions.

    There are a …

  8. Starting Design

    A few weeks ago now we started discussing ideas for what our robot might look like. I asked John to come up with some ideas and he was initially enthusiastic about drawing. His idea of a robot does seem to be mostly based around a somewhat boxy but humanoid form …