The usual input device for playing a synthesizer is the good old piano keyboard. However, you don’t have to stick to such pedestrian interfaces when making music. [Daisy] has a fun build that shows us how to put together a ribbon synth that makes wonderful little noises.

Naturally, the heart of the build is a ribbon potentiometer (also known as soft pots). It’s essentially a touch sensitive strip that changes in resistance depending on where you touch it. You can slide your finger up and down to vary the output continuously; in musical contexts, they can behave rather like a fretless instrument. [Daisy] employs one of these potentiometers in such a role by hooking it up to a Daisy Seed microcontroller board, which reads it with an analog-to-digital converter (ADC). The resistance values are used to vary the pitch of a dual-saw synthesizer programmed in the plugdata framework.

We’ve featured some other great ribbon synths over the years, too, like this tribute to the Eowave Persephone. They’re not the ideal choice for those that prefer their notes on pitch, but they’re beautifully fun to play with when you’re getting a little more experimental.

There’s just something about an analog synthesizer. You’d think that for electronic music, digital sampling would have totally taken over by now, but that’s really not true. The world of analog synths is alive and well, and [Polykit] has a new, open-source polyphonic synthesizer to add to the ever-growing chorus of electronic instruments.

The analog part is thanks to the eight identical voice cards that plug into the machine’s mainboard: each one has a voltage controlled oscillator to generate tones, an envelope generator, multiple voltage-controlled amplifiers, and even a pole mixing filter which is also, yes, voltage controlled. Each voice card outputs stereo, and yes, there are controllable mixing circuits for left and right output.

All that voltage control means a lot of lines from digital-to-analog converters (DACs), because while this is an analog synth, it does have a MIDI interface, and that means that a microcontroller needs to be able to speak voltage. In this case, the brains are an ATmega2560. Instead of stacking the board with enough expensive DACs to interpret the MCU’s digital signals, [Polykit] is instead is using some clever tricks to get more work out of the one DAC he has. Some things get tied together on all eight voices, like the envelope parameters; other values are run through a demultiplexer to make the most possible use of the analog lines available. Of course that necessitates some latching circuitry to hold the demuxed values on those lines, but it’s still cheaper than multiple high-quality DACs.

It’s a well-thought out bit of kit, down to the control panel and acrylic case, and the writeup is worth reading to get the full picture. The voice cards, main board and control board all have their own GitHub repositories you can find at the bottom of the main page. If you’re into video, [Polykit] has a whole series on this project you might want to check out on Makertube; we’ve embedded the first one below.

If you want to get your toes wet in the wonderful world of synthesizers, this library of seventy synths is an amazing place to start, because it has great simple projects.

Thanks to [Polykit] for the tip!

We absolutely adore inspired labor-of-love tales such as this one. [Alastair] wanted to build a synth for his daughter’s third birthday in spite of having no prior hardware knowledge. It became the perfect excuse to learn about CAD, microcontrollers, PCB design, and of course, 3D printing.

So, why a synth for a toddler? Aside from plain old ‘why not?’, the story goes that she received a Montessori busy-type board which she seemed to enjoy, and it reminded [Alastair] of the control surface of a synth. He wondered how hard it could be to build something similar that made sound and didn’t require constant button presses.

[Alastair] began his journey by dusting off a 15-year-old Arduino Inventors Kit. The initial goal was to get potentiometer readings and map them to 12 discrete values, and then emit MIDI messages. This was easy enough, and it was time to move to a synth module and an Elegoo Nano.

The full adventure is definitely worth the read. Be sure to check out the pink version in action after the break. You really don’t wanna miss the lil’ panda bear. Trust us.

Thanks for the tip, [dole]!