About a month ago, my youngest daughter borrowed a really neat toy called “Talkative Chick’s House Ppiyak-e House Bird Toy Mimiworld”, who’d brought the toy back with her on a trip from Korea.
The toy consists of a little bird, and a little bird house. The bird house has four activities for the chick. When the chick is placed over one of the play areas, a sound effect is played – the coolest of which was a washroom. You can kind of get the idea from this YouTube video (skip to 7 minute mark).
In any case, this was inspiration for a project I thought would be fun for she and I to work on together. Although I knew this wouldn’t be slick, I thought the quickest and easiest way to do this would be:
- Use a hall effect (magnet) sensor as a contactless sensor
- Install a magnet in a stuffed toy (not suitable for small children!)
- Take readings from the sensor with an Arduino
- Interpret the readings and play a selection of sound effects on a PC
We took a shoebox, and she built a home for a small stuffed toy, a “Teany Ty” she named Jelly. I cut open the the stuffed toy, and installed a couple of magnets, and sewed it back up. I picked up some hall effect (magnet) sensors from Creatron, and wired it up to an Arduino nano, and installed the sensors in key areas of the home.
I wrote a few lines of Python to read the data from the Arduino, and play back the samples. I’d never used Python before, and had heard about the PyGame libraries for years – I thought it would be rock solid, but even within a minute of play, with my setup, I had issues with MP3 sound effects that others had encountered as well. I converted them to WAV files and that went away.
We had fun picking and recording samples, eating and slurping water into the microphone. Freesound was a great place to look for sounds, though it didn’t quite have the breadth that my daughter was looking for (“I want a recording of a tiger walking on dry leaves”).
The sensor/magnet combination I chose wasn’t quite sensitive enough – the tiny magnet in the stuffed toy had to be really close to the sensor to trigger the sound. It does work, and it was a fun build.
Source Code: ProjectBird.zip