This week’s flashback installation comes from lucky MAKE Volume 13: the R-Tronic 8-Bit Toy Music Sequencer by Brian McNamara. Phil Torrone originally blogged this sequencer about 2 years ago. He had seen it on Etsy, made by seller RareBeasts (Brian’s shop). Brian shared this how-to with us about a year later in Volume 13.

As Brian describes in the intro:

I wanted to make a unique present to give my daughter for her first birthday, a musical toy that she could sit down and play with immediately but that would also become more educational for her in a few years. So I built her the R-Tronic 8-Bit, a simple music sequencer that lets you build up, play back, and edit musical patterns. It uses wooden shapes as buttons, and LEDs instead of fancy displays.

I started on the project 3 months before my daughter’s birthday, programming a Picaxe microcontroller with a speaker on a breadboard, using just enough software to make the sequencer’s 4 noises. Then I added 4 switch inputs to trigger the sounds, followed by 12 LED blinkies. I ported the tangled breadboard circuit to a neat printed circuit board, and finally built the wooden frame and fit the electronics. The final wiring was completed the night before my daughter’s birthday party.

If I had any worries that she wouldn’t like the R-Tronic, I needn’t have. As soon as she saw it, she knew just what to do.

The R-Tronic loops sounds in sequences that are 8 beats long. LEDs along the top flash in series to show which beat it’s on. Push one of the shape pegs, and it adds its corresponding sound into the repeating sequence, at the current beat, overwriting other sounds (or erasing it like a toggle if the same sound is already there).

Here’s a glance under the hood:


And here is the project shared with you in our Digital Edition, so you can get started building for your favorite future circuit bender.

You can also still pick up back issues of MAKE 13 in the Maker Shed. Lucky 13 is the Magic issue, loaded with telekinetic pens, levitating heads, ghostly blocks, fireball shooters, plus dozens of other projects, ideas, tips, and tricks for doing everything from growing giant vegetables to finding lost screws.