Connecting Sounds With Objects
Combining object sensing with sound is more powerful than you might think. The most obvious application is just for the bear to make appropriate noises in response to other toys. But what about interacting with other objects, besides toys? An ID tag stuck inside the cover of a book can trigger the bear to read it. A tag in a CD case can trigger the bear to play the corresponding music, without a small child’s having to fuss with smudge- and scratch-prone CDs or age-inappropriate computers.
If you have a child who just won’t listen to you, maybe they’ll listen to their friend the bear. Record some tags in “bear voice” saying that it’s time to go to sleep or time to brush our teeth. And don’t forget to give the parents a keychain RFID tag that has no sound associated with it. This very handy tag will instantly make the bear go silent! These are some of the Charlie’s Bear sound applications I’ve used successfully with the kids in my life, and I’m sure you can come up with many more.
Mod Charlie’s Bear!
The software for Charlie’s bear is fairly straightforward and easy to modify. For example, the existing code interrupts the current sound playing when a new tag is brought into range, but you can change its behavior so that it plays the current sound file until the end before starting the new one.
There are a few obvious physical modi-fications you might like to try. The bear has no power switch, so to turn it off you need to unplug the battery pack. Instead, you could add a switch inside a paw or combination of paws.
Alternatively, you might like to add some kind of motion-sensitive switch and modify the code so it uses less power when idle. With software power management, turning off the RFID antenna will save the most power. Then the batteries will last long enough that you might never need to switch your bear off.
Or maybe the bear would like to dance along with the sounds it makes? Consider adding a vibration motor or stepper motors that the Arduino can trigger along with the sound files. Perhaps you can modify the code so that some tags play sound and others cause vibration or movement.
Let us know how you use Charlie’s Bear!
This project first appeared in MAKE Volume 28, page 106.