Moon Germs

A one-handed portable synthesizer from the future

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A fun, pocket-sized synthesizer that uses an IR proximity sensor to modulate frequency. Using a combination of buttons and triggers, the device can produce several different waveforms and effects. An 8x8 LED matrix shows useful and colorful information while in use. I wanted to explore digital synthesis using the Teensy Audio shield and experiment with a unique way of interacting with a synthesizer with minimal buttons/knobs, all while designing a device with an interesting and retro form factor. Check out some demo videos here: and

Traditional synthesizers can be intimidating to approach with all their knobs and sliders, and difficult for a beginner to understand. This project aims to provide a fun and addicting way to mess around with a couple different waveforms and  explore creative and strange musical ideas. With only 4 buttons, and 2 analog inputs, interacting with the Moon Germs synthesizer and creating sound is really simple. Simply press down the "play" button and move your hand around relative to the IR sensor. Cycle through various waveforms with button 2, and switch octaves with buttons 3 & 4. For a "fatter" sound, apply force to the trigger to detune oscillator 2. The 8x8 display shows what type of waveform you're hearing, and dynamically speeds up or slows down with pitch.

For full details check out my github page for this project:

A zip file of the full GitHub repo. Includes all instructions, BOM, files etc.

x-zip-compressed - 18.55 MB - 10/15/2018 at 02:49


  • 1 × Teensy 3.2 Development Board, no headers $19.80
  • 1 × Teensy Audio Adapter $14.25
  • 1 × 4mm M2 Plastic Screws $7.50
  • 1 × 8mm M2 Plastic Screws $8.12
  • 1 × Adafruit PowerBoost 1000 $19.95

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  • Finalist!

    Kenneth Marut4 days ago 0 comments

    Super excited to have made it through to the finals! I'm really proud and honored, thanks to the judges for liking my work!

    With that being said, the deadline for the finalist submissions is less than a week away, but I'm going to see if I can work in a couple more interesting features before then. As I've been thinking more and more about this project, I've really started to get a better feel for what this instrument does best. I've realized that as a monophonic, drone-y noise machine, this synthesizer sounds best in the lower registers. The de-tune feature really fattens up the sound and really reminds me of this track from the Blade Runner soundtrack. In the next couple days I'm going to see what I can do to widen the preset sounds even more and make them more dynamic. I'm also going to decrease the range of the instrument so that it focuses more in the lower range. 

    I'm going to take a shot at building a simple desktop app to build your own custom sounds with minimal knobs/sliders. I want the entire experience of using the device to be straightforward and easy to use, but still very dynamic and fun!

     We'll see how far I get...

  • Finishing up

    Kenneth Marut10/07/2018 at 17:30 0 comments

    I'm currently in the final stages of completing the assembly and am now working on some documentation so I can submit this thing before tomorrow! I'm pretty happy with the results so far, and will be messing around with it all afternoon in an attempt to create something musical. I've updated the project's github page with a ton of information, photos, and files (, and will be uploading some more detailed photos and videos later today.

    The final model!

    The whole assembly

    Thoughts and Ideas:

    As I've been finishing up this version, I've had a couple thoughts and ideas about where to go from here. Although the device is fun to play with and easy to use, its current feature set is a little bit limited (which is okay). I am exploring the idea of creating a simple desktop app which can interface with the device over USB to allow deeper exploration into sound creation. The app would provide the user with a simple GUI with some knobs and sliders, and a way to preview and save sounds. The GUI could also have a graphical representation of the 8x8 matrix to allow the user to "draw" their own images to be associated with each sound. The saved sounds and 8x8 image would be then stored on the device. Below is a quick concept sketch of the app:

  • PCBs and more testing

    Kenneth Marut10/04/2018 at 19:33 0 comments

    The PCB breakouts for the Teensy finally arrived and I proceeded to hook everything up, so far so good! Currently working on some of clean up and finalizing the code for the first prototype. 

  • More printing + coding

    Kenneth Marut09/25/2018 at 21:37 0 comments

    After a bit of fiddling around with my Wanhao D7 resin printer, I've finally settled on some enclosure prints that I'm happy with. Printing with resin has its own set of challenges that can be tricky to work through, especially with larger parts. There's a good bit of post-processing involved once the parts come off the machine (removing supports, UV curing, sanding, drilling) and it can be a pain.

    In the meantime I've also been working pretty hard on writing code for the Teensy. It's been pretty interesting playing with the audio shield and I'm happy with the results so far. The basic synth I've designed has 2 main oscillators, a filter and an envelope (these are configurable via code, so I can easily change it up later on if I want to). I've mapped the IR sensor to the oscillators' frequency and also added functionality for octave shifting and a low-pass filter that can be adjusted with the linear pot trigger. I've also been manually drawing out frame-by-frame dynamic animations for the 8x8 dot matrix display, and they're looking pretty cool so far!

    I'll be traveling for the next couple of days for a wedding so I'm trying to get as much as possible done before that. Hopefully when I get home my PCB's will be waiting for me in the mailbox!

    Fitting the components in place:


    Synth block diagram (subject to change):

  • Resin Printing

    Kenneth Marut09/22/2018 at 16:08 0 comments


  • Finishing up enclosure design and moving on to some coding

    Kenneth Marut09/19/2018 at 23:03 0 comments

    I've been trying to finish up the housing over the past 2 days. I think I'm pretty close to being done. Currently printing out a couple quick prototypes on my FDM machine to test fit everything and if everything looks good I'll send it to the resin printer.

    I've started laying out the Arduino code and have been playing with a couple of the audio shield's features. I'm not entirely set on what I want each button to do, but hopefully after a bit of messing around it'll start to become a little more obvious.

    In the meantime, check out some renderings I did of the enclosure:

  • 1-Day PCB design, hope it works...

    Kenneth Marut09/17/2018 at 15:48 0 comments

    I was able to knock out the schematic and layout for the PCB last night and this morning. I used the Fusion 360 + Eagle integration to generate a pretty cool board outline and was able to seamlessly work between the two CAD programs. Routing the board was a little tricky, but ultimately not that bad. I sent off the Gerber files to Seeed for manufacturing (I had a $1 coupon for 3 PCBs, making the total cost $18 including shipping, incredibly cheap!). Let's see how fast they can turn this around.

    The "triple stack" of PCBs

  • Wiring things up + planning the PCB

    Kenneth Marut09/16/2018 at 17:06 0 comments

    Hooked up everything to a breadboard and ran some preliminary tests using the Arduino IDE to check connections and functionality. So far so good! The 8x8 matrix and teensy Audio shield share the same I2C bus and everything seems to work fine. I was able to get the device to generate some audio waveforms while also displaying some simple images on the matrix (what a relief). 

    I've also decided that I'm going to go ahead and try to crank out a PCB breakout for all these components before the submission deadline. It should be pretty straightforward, but I'm a little bit concerned about the lead time. If I can get this thing sent out by the end of the day tomorrow, I think I'll feel pretty good. I've marked out all the pins I'll be using and started creating my EAGLE library. Between the pins being used by the Audio shield and the pins I'll be using for my additional components, I have a single free pin left (17), pretty lucky! 

  • Bredboarding and prototyping

    Kenneth Marut09/14/2018 at 21:26 0 comments

    Just spent the afternoon soldering wires to all my components and terminating them with some 0.1" headers for easy breadboarding. The enclosure prototype just came off the machine and things are starting to fit pretty nicely! 

    It's been a very productive day, now time for a beer or 3.

  • Component layout + plastics design

    Kenneth Marut09/14/2018 at 19:30 0 comments

    Trying to move quickly here! I've laid out my internal component structure and started shelling out the  2-part enclosure and adding mechanical mounting features. For the final design, I'm planning to 3D print the enclosure using my Wanhao Resin printer, so I thought it was best to design the enclosure as if it were to be injection molded (ribs, bosses , etc). Going about it this way will allow me to save on resin and also prevent warping during the print process. 

    Some cool mechanical features that I've incorporated into the design:

    • Mechanical "Cherry" keyboard switches as inputs
    • A springloaded linear pot with trigger. Sot sure exactly what I'll be controlling with this, but it should be a pretty fun input

    I'm currently printing a prototype of the enclosure's lower half to test fit my components. If everything looks good I'll move on to the upper half (this is where I'll be housing the 8x8 LED display and LiPo charger.

    In the meantime, I've started breadboarding my circuit. Once I get a proof-of-concept, I'll probably transfer everything to a perf-board. Ideally, I would like to make a custom breakout PCB, but I don't know if I can afford a 10-day lead time on manufacturing!

    Still a lot to do! 

    Check out a quick rendering I did in Fusion 360 below:

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Enjoy this project?



Nathan Stanley wrote 09/20/2018 at 04:03 point

Looks very cool! I'm keen to hear what kind of sounds it will make.

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