24-03-2020

Shedric gets all animated

Click the image to step through.

While we're closed, I thought it might be a good idea for us to write about projects we have done at the Shed, so I'll start with a piece about Shedric. He's a bit lonely at the moment, but setting a good example by avoiding social contact. Unfortunately that also means that we can't get a video or picture of him at the moment either.

The idea was to have a mascot to attract attention at fairs and in window displays. The torso came from M and S when they closed, and it was just an afternoon's work to make his head and limbs, using saw handles for the ears and folding rulers for the arms.

I had always wanted to animate him and thought maybe a windscreen wiper motor could wave his arm back and forth, but then Chris Nixon found me a Raspberry Pi computer and introduced me to a whole new world.

There's any amount of stuff on the web about using the Pi to control robots and wacky vehicles, and a lot of it is aimed at ten year-olds. But that's OK. We're all ten-year-olds at heart, just with a bit more pocket money. And the pocket money goes a long way. I've been amazed at how cheap the components are. The simplest Pi is under £30, servos and sensors only about £2 or £3 each.

Milton and I have fitted a servo to pull the arm down, and a spring to pull it back up again.It took a while to get to grips with new concepts and terminology, but it is very easy to write programs to control a servo. In a language called Python you just tell it how many degrees to move, and how long to wait before doing something else. That was stage 1. I've now added a movement detector so that the servo program only operates when someone walks past.

At the time of writing (March 2020) Shedric just needs to be plugged in and he will wave his arm whenever he detects movement. It's all still very crude, but it's been fun to do.

During our lockdown I can't make any progress, but I'm thinking about what to do next. Maybe some LEDs to make his eyes flash. Any suggestions?