This whole thing started when my son Adam (who was 10 at the time) brought home a string of slightly decrepit Christmas Bells. He and his mom had found them at an after Christmas sale and bought them for a song (pardon the pun) - only about half the 12 bells were working! He spent the next hour with his soldering iron and wire strippers. Success! Well, if you define success as 12 very loud and piercing bells playing the same 25 Christmas songs over and over again...

After 2 weeks of non-stop ringing, I was blessed with silence one day and discovered Adam at the computer with an open spreadsheet at least 1000 lines long. "What are you doing?" I naively asked. "Trying to figure out a way to get the bells to play through the computer." Apparently he was creating his own version of a music box. Confused, I asked if he was using MIDI from the computer, and his eyes got huge. "MIDI! That's it! Then I can play them from my keyboard, too!"

He had received a BASIC Stamp kit for Christmas, so he dug it out to check on its specs. Serial Input was too slow for MIDI. "Dad, can I have a Propellor chip?"

We finally got the Propellor chip last summer (special thanks to the great people at Parallax for their support), and he was off and running. Tom Dimock had created MIDI In Spin Object, so the hard part of the programming was complete. We dissected the old bells and discovered how to drive the solenoids (here's a wonderful You tube video we found that explains the bells better), found the MIDI specs, and drew up schematics. Adam breadboarded the whole thing and rewired the bells to have an RJ45 jack for easy connection. All we had to do was find the right solenoid timing and the contraption worked!

Of course, that wasn't enough for Adam - he had started devising many more uses, such as sequenced Christmas lights, sequenced fountains, and even a MIDI pipe organ! For years now he has also wanted to design a custom PCB, and we thought this would be a great opportunity. So he put the specs together and we drew the schematic, laid out the PCB, and had ExpressPCB deliver 4 beautiful boards. He was so excited the day they arrived he soldered the whole thing up right after school.

Last thing he wanted to do was make the bells more portable - they came in a long string that was unwieldy and tended to break the wires. So we built up an oak carillon tower and rewired all the bells into the tower. His music teacher at school was so excited she asked him to play it in a series of Christmas recitals!

Here's a YouTube video of the whole thing.

Great You Tube video I found  explaining the bells.