"tbish" update on "synthiota" board, jam starting at 1:20

video upload by todbot

"Start at 1:20 for a little fun jam.
Got some time to work on "tbish" TB-303 emulator in CircuitPython.
This video shows some of the updates.
The updates include:
new mapped_pot_controller to allow the pots to have different modes
sequencer has separate lane for slides so that accent & slide can happen on same step
tbish_synth now has 4 different waveforms to choose from
can edit the sequence steps, both notes and accents/slides/mutes
can switch between sequences
can adjust bpm & steps_per_beat
actually using the LEDs

code and schematics: https://github.com/todbot/synthiota

#tb303 #circuitpython #raspberrypipico"

previously:

"tbish" almost on "synthiota" board

video upload by todbot

GreyScale-KOSMOS #raspberrypi #pico #rp2040 #midi #sequencer #algorithmic #generative #kosmos

video upload by plantssystem

Follow-up to this post.

"KOSMOS – A Compact Generative Sequencer Driving the Prophet‑5

This short clip features KOSMOS, my standalone generative MIDI sequencer, controlling a Sequential Prophet‑5. KOSMOS creates evolving melodic patterns and rhythmic variations in real time, while the Prophet‑5 provides its unmistakable analog warmth and depth.

The performance is completely autonomous — no DAW, no external processing — just KOSMOS generating the sequence and the Prophet‑5 responding with its classic tone.
It’s a small glimpse into how KOSMOS interacts with hardware synths and how expressive the pairing can be."

An eyebrow-raising MIDI controller for $35

video upload by Floyd Steinberg

"Mediapipe + OpenCV caused a big stir some 4 years ago, but I never got around trying it myself. Until today, and of course I'm sharing my results with you. This Open Source software can detect gestures, poses and facial expressions and transform them to so called landmarks that can easily be used for all kinds of shenanigans (in this example: controlling your synths).

00:00 introduction: what's this?
00:38 demo 01: playing chords + bass + controlling filters
01:32 hardware needed
02:12 installation
02:56 what are OpenCV and Mediapipe?
03:55 this example explained: reading landmarks, converting to MIDI
06:35 demo 02: controlling an arpeggiator
07:37 demo 03: controlling filter cutoff frequency and pitch bend with my eyebrows
09:21 demo 04: playing pads on Akai MPC Live 3 with backing track
10:10 conclusion / do the YouTube thing!"

Where to get the stuff: [affiliate links]
Mini camera: Amazon DE | Amazon US
RasPi Zero 2: Amazon DE | Amazon US
SD card: Amazon DE | Amazon US

Installation instructions

sudo apt update
sudo apt upgrade
pip install mediapipe opencv-python --break-system-packages
git clone https://github.com/mrfloydst/eyebrowr...

then python3 ./hand.py or python3 ./eyebrow.py

HÄLP ZIS CHANNEL
https://www.patreon.com/floyd_steinberg
https://floydsteinberg.gumroad.com/
https://floydsteinberg.bandcamp.com/"

GreyScale – A Standalone MIDI Sequencer KOSMOS Powered by Raspberry Pi Pico (RP2040)

This one is in via GreyScale aka plantssystem whose videos you have likely seen on the site.

"GreyScale is a compact, self‑contained MIDI sequencer built entirely around the Raspberry Pi Pico (RP2040).

Its minimal hardware footprint hides a surprisingly deep generative engine, combining Euclidean rhythm generation, step sequencing, probability control, and evolving melodic behavior.

The clean GreyScale UI provides immediate visual feedback — step activity, Euclid parameters, probability states — all rendered on a crisp LCD. A joystick and four dedicated buttons offer fast, tactile control, keeping the workflow musical and instrument‑like rather than menu‑driven.

GreyScale runs completely standalone with standard MIDI output, making it an ideal partner for hardware synths, desktop modules, or DAW setups.

Designed for spontaneity and long‑form generative performance, it encourages exploration and rewards experimentation. A small instrument with a refined feel, GreyScale blends DIY charm with a polished, modern sequencing experience."

Update: demo here.

CLICK FOR MORE »

Bizarre Love Triangle/New Order (Circuit Tracks & MiniDEXED version)

video upload by Guinan

"‘Bizarre Love Triangle’ from 1986 is first off the rank for my ‘New Order February’ recreations.

I love this perfect slice of dance-synth-pop and I was keen to get the DX7 bass intro as close as I could. Earlier this week I’ve been showing the tiny $75 Raspberry Pi synth, MiniDEXED, that I built to add this vital ingredient. If you are interested check out the video showing more details, • I made a synth for $75* ! (*excluding tar... [posted here]

A couple of very clever folk identified what I was cooking up!

The MiniDEXED was sequenced from the MIDI tracks on the Circuit Tracks and routed into the audio in to add effects from the Tracks. All that you hear was programmed into the single Circuit Tracks and no further additional synths or processing were done to the sound – it’s straight audio out recorded direct into a Zoom L6.

The arrangement was taken from several versions posted on Musescore and compressed into the 4 melodic tracks and rhythm. Thanks to everyone who posts their transcriptions there.

I hope you enjoy the track as much as I did making it. Stay tuned for more New Order recreations and reworkings for the rest of this month.

(Ableton Move version coming in just a couple of days...I'll post a link here when it's live).

CLICK FOR MORE »

Making ANOTHER $75 synth! (MT32-pi)

video upload by Guinan

Follow-up to this post.

"I made ANOTHER Raspberry Pi-based $75* synth to pair with my Circuit Tracks.

(*approx price depending on a whole bunch of local factors...)

The commentary is long and unscripted (full of ums & errs!) so if you want to jump to a particular section the sections are as follows,

00:04 Intro
00:21 MicroDEXED synth
01:00 MT32-pi
01:52 Why emulate the Roland MT-32?
02:55 General MIDI vs. MT-32
04:03 Soundfonts (.SF2)
05:21 MT32-pi bootup
05:55 JV-1010 emulation soundfont demo
08:23 Using the Circuit Tracks Mixer and Effects on the MT32-pi
09:55 Selecting presets from the Tracks
12:00 Conclusions

This time I've used open-source hardware and software designed around the MT32-pi project. See link here,
https://github.com/dwhinham/mt32-pi

There's a very excellent detailed build and demo video from ‪@mr_floydst‬ here, • MT32-Pi DIY synthesizer: bare metal 80s no... [below]

Oddly the hardware worked out cheaper (despite a bigger display) as this is a commoner target build.

This excellent project uses any Pi from the Pi Zero 2W upwards to recreate a multi-timbral emulation of the Roland MT-32 synth and also act as a player for soundfonts in the .SF2 format.

Roland MT-32,
https://en.wikipedia.org/wiki/Roland_...

Editing software and library of downloadable soundfonts,
https://www.polyphone.io/en/soundfonts

I used a pre-assembled hardware kit from Ebay with a Raspberry Pi Zero 2W (with header). The assmbled complete hardware can also be bought from sites such as Etsy etc."

MT32-Pi DIY synthesizer: bare metal 80s nostalgia

video upload by Floyd Steinberg

"This week, let's build and take a look at the #MT32 PI, another "bare metal" synthesizer running on #RaspberryPi. This is an emulator for the late #80s Roland MT-32 sound module, which was used by a lot of games for their sound track. The MT-32 PI can also load soundfonts, so you can use it as a ROMpler in your setup. Table of contents:

00:00 introduction
00:36 hello
01:28 hardware needed
02:34 breadboard explained
03:09 building the UI
03:28 wiring
03:55 LCD setup
04:32 software installation, ROMs and soundfonts
05:04 config file setup
05:31 using the device, soundfont editing
06:31 important considerations
06:48 demo 1 (MT-32 emulation)
08:43 demo 2 (soundfonts)
09:45 bye-bye

HÄLP ZIS CHANNEL
https://www.patreon.com/floyd_steinberg
https://floydsteinberg.gumroad.com/
https://floydsteinberg.bandcamp.com/"

He Made a synth for $75* ! (*excluding tariffs/postage...)

video upload by Guinan

"I made an open-source Raspberry Pi based DX-emulation synth for around $75 and hooked it up to my Novation Circuit Tracks.

MiniDEXED is the open source DX emulation project,
https://github.com/probonopd/MiniDexe...

I used the following open source hardware Raspberry Pi HAT which delivers a DAC and DIN MIDI in and out, https://github.com/tebl/BulkyMIDI-32

Build is also here, https://www.pcbway.com/project/sharep...

I ordered mine pre-built from Ebay - but that's just a reflection on my soldering skill!

To run the software it also needs a Raspberry Pi Zero 2 (buy one with a 'GPIO header' as then it's just plug and play once you have loaded the software from the above link). Make sure it's a 'Zero 2' as the older model is much slower.

Much more detail and slicker presentation here....
• MINIDEXED - honey, I shrunk my DX7 collection [posted here]

All of the above work was inspired by the very excellent and similar MT32-pi project by Dale Winham which emulates the Roland MT-32 synth and others. I've got a 2nd Pi Zero 2 and some parts in the wings for a further video...."

Roland Future Design Lab and Neutone Introduce Project LYDIA

Press release follows:

A Technology Preview Exploring AI, DIY Culture, and the Future of Music Creation

Los Angeles, November 11, 2025 — Roland Future Design Lab, the advanced technologies research group of Roland Corporation, announces Project LYDIA, an audio processing platform preview created in collaboration with Neutone, developers of next-generation AI tools for musicians and artists. Project LYDIA merges Neutone’s trainable AI software with Roland’s hardware expertise, using a Raspberry Pi 5 single-board computer to deliver a compact, stage-ready prototype that reimagines DIY innovation for a new generation.

Bridging AI and DIY Creativity
Roland’s legacy in DIY music creation began in 1981 with AMDEK (Analog Music Digital Electronic Kits), a line of build-it-yourself kits that encouraged musicians to experiment with technology. Today, Roland Future Design Lab revisits that spirit, asking how modern creators can explore sound through emerging AI tools.

AI for Sound Discovery and Exploration
Powered by Neutone’s Morpho technology, Project LYDIA, named after DIY and AI, uses “neural sampling” to learn the tonal qualities of any sound and apply it to another in real time, with the sonic results ranging from highly musical to exotic and surprising. The current Project LYDIA mockup houses a Raspberry Pi 5 computer running Neutone’s special version of Morpho alongside Roland’s latest ideas for a simple, tactile control panel. Audio I/O is currently managed via a USB-connected Roland Rubix interface, with future iterations aiming to fully integrate I/O for a completely self-contained device.


AI Innovation at Roland
Project LYDIA builds on Roland’s growing exploration of AI as a creative partner for musicians. In 2024, Roland and Universal Music Group (UMG) jointly introduced the Principles for Music Creation with AI, a framework outlining shared commitments to ethical and artist-centered innovation.
“Roland has taken a leadership role globally in practicing responsible development with AI for music creation,” said Paul McCabe, Senior Vice President of Research and Innovation at Roland. “Part of being responsible is getting input from creators on what they find useful, helpful, or inspiring, and what ideas may not be welcome in their workflows. Releasing Project LYDIA as a technology preview allows us to demonstrate possibilities, seek community input, optimize, and improve.”

Shaping the Future Together
Project LYDIA debuted at the Audio Developer Conference taking place November 10 through November 12 in Bristol, UK, inviting feedback from the creative community to guide future research in AI-driven music tools. Musicians and makers can share their thoughts and ideas via a short survey here.

To learn more about the inspiration and technology behind Project LYDIA, visit Roland’s feature story on Roland Future Design Lab.

CLICK FOR MORE »

Tiny Sequencers Compared -MicroDexed, Picotracker, Woovebox, RK-008, MEDO, Elecrow MINI PC & more

video upload by Floyd Steinberg

"In this video, I compare 6 compact hardware sequencers and a Raspberry Pi 5-based Mini DAW by Elecrow https://www.elecrow.com/small-mini-pc... . Whether you're into grooveboxes, trackers, or portable MIDI tools, this roundup covers everything from connectivity to workflow.

🔍 What’s inside:
Track counts & sequencer types
MIDI options: TRS, DIN, USB
Battery-powered gear
Workflow & usability
Raspberry Pi 5 Mini DAW with OLED screen & PCIe SSD support

🕒 Timestamps
00:00 this looks nice :-)
00:10 the idea
00:33 overview
01:05 the Monkey
05:07 the Tracker
08:21 the wannabe PC
10:47 the mini groovebox
14:16 the underrated
17:57 the rectangle
21:14 the serious one
24:29 grouping these by category: which ones have batteries, which ones have TRS MIDI, ...
25:15 subscribe kkthxbye

🔗 Gear featured in this video:
RasPi Mini PC DAW: https://www.elecrow.com/small-mini-pc...
MicroDexed: https://codeberg.org/positionhigh/Mic...
Woovebox: https://www.woovebox.com/ Monkey: https://wavyindustries.com/monkey/
Picotracker: https://xiphonics.com/
MEDO https://www.donnermusic.com/products/...
RK-008: https://www.retrokits.com/rk008/
Geonkick https://geonkick.org/
Surge XT https://surge-synthesizer.github.io/
ZynAddSubFX https://github.com/zynaddsubfx/zynadd...
TAL Noisemak3r https://github.com/Nexbit/tal-noisemaker

HÄLP ZIS CHANNEL
https://www.patreon.com/floyd_steinberg
https://floydsteinberg.gumroad.com/
https://floydsteinberg.bandcamp.com/"

PlantsSystem-PRA32-U

video upload by plantssystem

"Build your own digital synth with PRA32-U × Raspberry Pi Pico!

ISGK Instruments' PRA32-U is a digital synthesizer that uses Raspberry Pi Pico.
The Pico and various circuits can be arranged smartly, making prototyping and modification a lot of fun, and allowing you to quickly put your ideas into shape.
This time I put together everything from MIDI input to sound generation and output, and it was extremely easy to use as the foundation for a homemade synth, and it was a very fun experience to build it."

https://risgk.github.io

Overview

4 Voice Polyphonic/Paraphonic Synthesizer for Raspberry Pi Pico 2/RP2350

Built-in Chorus and Delay FX

Controlled by MIDI -- PRA32-U2 is a MIDI sound module

Having the function of writing the parameters to the user programs and the flash

Modifiable with Arduino IDE and Arduino-Pico (by Earle F. Philhower, III)

An I2S DAC hardware (e.g. Pimoroni Pico Audio Pack) is required

PWM Audio can also be used instead of I2S (PWM Audio does not require an I2S DAC hardware)

Prebuilt UF2 files ("bin")

"Digital-Synth-PRA32-U2-Pimoroni-Pico-Audio-Pack.uf2" is for Raspberry Pi Pico and Pimoroni Pico Audio Pack

"Digital-Synth-PRA32-U2-PWM-Audio.uf2" is for Raspberry Pi Pico and PWM Audio

Bottom pic with control panel.


Demos by the maker Ryo Ishigaki:

MIDI Controller PRMC-1 (type-0) Demo (2025/04/13)

video upload by Ryo Ishigaki

Digital Synth PRA32-U with Panel Prototype 2 Audio Demo (2024/09/11 v2.5.1)

video upload by Ryo Ishigaki

Clockwork PI, ESI XSynth - when these work together, it's awesome (lots of sound examples)

video upload by Floyd Steinberg

"The ClockworkPI u console is a so-called Cyberdeck (think oversized Blackberry) powerful enough to run DAWs. The ESI XSynth is a digital synthesizer that registers both as an audio interface and as a MIDI keyboard. Now this should be the perfect match, right? Table of contents:

00:00 sound example
00:05 hi
00:20 what on earth is this
01:19 what is the XSynth?
02:07 hello linux
03:13 patch examples: A001 XSynthGo (Poly AT demo)
03:37 A006 LoFiPicks
03:54 A008 Fatness
04:13 A009 Whales
04:26 A015 On Clouds
04:47 A028 7Flower
05:42 A074 Pianism
06:05 A102 LeGrand
06:45 B060 EP Pad
07:18 B075 RevPad
07:48 some patches I made: C001 Nostalgia
08:40 C002 David
09:07 C003 Warm Pad
09:42 C004 Chaos
10:00 C005 TR909L
10:14 XSynth Architecture: Creating a patch with FM, PWM and Ring Modulation, Mod Matrix, Effects, ...
15:25 Layering tracks on the ClockworkPi to create this track (XSynth only)
17:16 some thoughts on this setup
18:35 bye, subscribe, support

Links:
ClockworkPI https://www.clockworkpi.com/home-ucon...
Clockwork OS https://wiki.clockworkpi.com/ClockworkOS
Reaper https://www.reaper.fm/

CLICK FOR MORE »

【新・楽器開発してみた 1】自作MIDIコントローラーのテストプレイ / yummy / raspberry pi pico

video upload by - WASHIYAMA GIKEN -鷲山技研

"自作の楽器「key-bowed」と同じような操作感で既存のシンセサイザーを演奏するためのMIDIコントローラー「yummy」を作成しました

「yummy」は
　7月5日「Hamamatsu Micor Maker Faire 2025」
で展示するので興味のある方はぜひいじりにきてください！

◆ X : https://x.com/washiyamagiken
◆ BLOG : https://washiyamagiken.hatenablog.com/"

Googlish:

"I created a MIDI controller called "yummy" to play existing synthesizers with the same feel as my homemade instrument "key-bowed". "yummy" will be exhibited at "Hamamatsu Micor Maker Faire 2025" on July 5th, so if you're interested, please come and play around with it! ◆ X: https://x.com/washiyamagiken
◆ BLOG: https://washiyamagiken.hatenablog.com/"

Module X – A Modular Synthesizer based on Sunvox

video upload by Marco Antonio Müller Lopez

"Module X is an extremely flexible modular synthesizer with an interface that adapts to a wide range of needs. The system is powered by a Raspberry Pi, an Arduino Due, and a 192 kHz audio interface from Pisound. It uses the open-source software SunVox for sound synthesis. With SunVox, users can create any number of virtual synthesizer and effect modules, making the sonic possibilities virtually limitless."

ZicBOX - DIY open source modular scalable groovebox

video upload by Floyd Steinberg

"The #ZicBOX Pixel is the smallest example built in the ZicBOX ecosystem. The idea here is modular hardware meets modular software, so you can quickly scale up or down your #synthesizer and #groovebox ideas with a couple of JSON files and some 3D printed enclosures. Sponsored by #PCBWay. Table of contents:

00:12 concept
00:45 PCBWay https://pcbway.com/g/4nkLCf
01:49 parts needed / costs
02:13 building the thing
06:30 installing the software
06:56 UI overview
07:15 using the thing
11:09 conclusion, and call for papers (coders and designers)
12:10 if you find my videos useful, please consider supporting this channel (building DIY devices and learning how they work and then making a video is expensive and time consuming)

Relevant links
ZicBOX gitHub https://github.com/apiel/zicBox
Bill Of Materials https://github.com/apiel/zicBox/wiki/...
PCBWay - https://pcbway.com/g/4nkLCf - you can upload the ZIP folder from the GitHub page there; the measures are 100x84,5mm - price is $5 per board with a minimum of 5 boards per order

HÄLP ZIS CHANNEL
https://www.patreon.com/floyd_steinberg
https://floydsteinberg.gumroad.com/
https://floydsteinberg.bandcamp.com/"

Additional designs:

Custom White MiniDexed - TX-816 in a tiny box

Note: links to listings are affiliate links for which the site may be compensated.

via this VEMIA listing

Click the auction link on top when you get there for additional listings.

VEMIA is Peter Forrest's auction house. He is the author of The A-Z of Analogue Synthesizer Books.

"What is it? MiniDexed is a high-performance FM synthesizer that replicates the sound of eight DX7 instances, delivering the iconic tones of the TX816 and TX802. Designed to run 'bare metal' on the Raspberry Pi, MiniDexed operates without the need for a Linux kernel or operating system, ensuring efficient and seamless performance. It is assembled into a custom made case, 3D printed. It’s ready for immediate use and compatible with any MIDI keyboard or sequencer featuring MIDI out. By default, its eight modules are assigned to MIDI channels 1-8, but these settings—and more—can be easily customized using the intuitive menu. Used just 3 hours: I had bought it just to compare it to my vintage TX816. I loaded the same sounds in either synth (yes, it loads by MIDI the DX / TX sounds!) and compared A/B. Simply UNBELIEVABLE. For a deep dive into MiniDexed's software and features, please visit this page."

CLICK FOR MORE »

Syd and I - Live at the Faight collective in San Francisco 2025

video upload by Saul Stokes - Frequensea

This one is in via supporting member Saul Stokes.

"Syd and I are a father-daughter electronic music duo. Our style of music comes from Syd's amazing singing, lyrics, and compositional skills combined with my 30-year history of electronic music. This is our first EP, 24 on 7. For our live sets, we have fine-tuned the perfect live show setup. Our entire set is battery-powered and built into a travel case. This allows us to set up and perform quickly anywhere. Contact me for booking possibilities! Check out the rest of our EP using the links below.

Instruments:
1010 blackbox
Novation Circuit Tracks
Korg Kaoss pad Nts-3
Rasperry Pi MiniDexed
Bastle Bestie
all battery-powered!

Spotify -
https://open.spotify.com/track/54cHys...

Bandcamp -
https://saulstokes.bandcamp.com/album...

Apple
/ syd-and-i

Thank you,
Saul

Follow us to stay updated on future live shows and new music.

ig@syd_and_i"

Teensy Audio Library on Raspberry Pi Pico 2 W

video upload by Ghost In Translation

"Raspberry Pi Pico 2 W is capable of running Teensy's Audio Library after some minor modifications.

Here I'm sending MIDI over USB to Pico which is running a 16 voices polyphonic synth sketch. The audio is then sent by I2S to a DAC (the same audio expander from my Motherboard).

There is some light cracking that is coming from the I2S library that I still need to take a look at, otherwise that chip is very capable."

Modu-Grain: The Ultimate Granular Synth for MODULOX BRAIN | Open-Source software & MIDI-Ready!

video upload by RaspiAudio



"🎛️ Introducing Modu-Grain: The Granular Synth for MODULOX BRAIN! 🎛️

🔗 More info & get yours here: https://raspiaudio.com/produit/brain

We're thrilled to introduce Modu-Grain, a powerful granular synthesizer for the MODULOX BRAIN, designed for music creators and sound designers! 🎶

🧠 What is MODULOX BRAIN?
The RASPIAUDIO team has spent two years developing an open-source audio synthesizer platform. Our vision? A versatile hardware unit capable of running multiple applications. This week, we're releasing the Granular Synthesizer, with more to come, including Sampler, VA, and FM. Our open-source code on GitHub allows the community to create and share new applications!

⚡ Why Modu-Grain?

Comes with pre-recorded samples
Four-voice polyphony for rich sound layering
Adjustable sound parameters (grain size, density, envelope, random playback, sample duration)
Real-time waveform visualization and boundary adjustments
Live sample recording via built-in mic or external input
Customizable real-time effects: Filter, Delay, and an assignable LFO
MIDI support for integration into any setup

💾 How does it work?

Precompiled firmware available in our [app store] (apps.raspiaudio.com)
Community-driven: Modify, enhance, and expand features!
🔧 MODULOX BRAIN Specifications:

24-bit DAC & ADC resolution
320x240 color screen
Headphone jack + onboard mic & speaker
MIDI in/out (3.5mm jack) + USB-C MIDI
Expandable via magnetic connectors for MODULOX devices (Knob, Touch, Slide)
Nano pad anti-slip bottom for stability

🎛️ Accessories Included:

3.5mm jack to MIDI DIN RX-TX + sync cable

🚀 Join the Open-Source software Revolution!
MODULOX BRAIN is more than a synthesizer—it’s a platform for endless sonic exploration. Download the firmware, modify it, and create your own instruments!

🔗 Get started now: https://raspiaudio.com/produit/brain

🔗 Explore the source code: [GitHub Link] (apps.raspiaudio.com)"

CLICK FOR MORE »

Zoxnoxious: The Four Voice Cards

video upload by Ultratroninator 3000

"Four voice cards developed (so far!). And their VCV Rack interfaces.

Up til now the voice cards were named based on the analog chip the card was designed around. The Z3340 for the Curtis / Alfa Rpar 3340 VCO, Z3372 for the Curtis / AS3372 chip, and the Z5524 for the Curtis / Alfa Rpar 3394 + SSI2130 (3394 + 2140 = 5524). A boring but technically accurate description.

The most recent card could have been named Z2140, for the SSI2140 filter chip. Or 2040, after the SSM chip it originated from. Z4330 would have also been acceptable given it's core function is SSI2140 + SSI2190 chips. However, nothing better describes its function than Pole Dancer. It's a rarity and deserves a name better describing the function. Take a great sounding analog filter, add voltage controlled mixing of the filter poles, and you've got the Pole Dancer. This voice card does a good job of realizing many many filter types. Lowpass, highpass, bandpass, notch, allpass. Along with morphing between them. Not to mention it has options for resonance compensation, something not present on other '2140 implementations. So boom. Baby. Boom.

Open source on github: https://github.com/brer-rabbit/zoxnox..."

DIY Oscillator using PIC12F1571

video upload by alloutofsync

"I used this weekend to create a square wave oscillator that operates with the PIC12F1571, which is an extremely affordable CPU available for just $0.71 each.

Since it was my first time using PWM, I spent an entire day generating a square wave at the desired frequency. The required settings and their interconnections were so complex to me, so that I had to carefully investigate each one as I went, which was quite challenging.

The next day, I spent working on ensuring that the output sound smoothly followed the CV input. To convert the CV input into a frequency assuming 1V/Oct, exponential calculations are typically used. However, the PIC12F1571 has limited program memory, so I couldn't use a floating-point math library. I had no choice but to approximate the calculation of powers of two using a Taylor series expansion and rely solely on integer arithmetic. Initially, I approximated up to the second-order term, but the accuracy was insufficient at higher frequencies. Eventually, I extended the approximation to the fourth-order term, which gave excellent results.

While testing with the Pico3 sequencer, I noticed that when the RATE was set to the maximum, the output failed to keep up with the changes. Increasing the PIC's clock frequency from 1MHz to 4MHz resolved the issue, and it followed the changes without any problems.

At this point, about 70% of the program memory has already been used, so I'm not sure how much further I can expand. At the very least, I want to implement duty cycle adjustment. If possible, I’d also like to use an additional PWM channel to detune and combine the signals for richer synthesis."