#pwm — Public Fediverse posts
Live and recent posts from across the Fediverse tagged #pwm, aggregated by home.social.
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FAKE- or Pseudo PWM - STM32 Bare Metal #9
In this video we will cover handling external interrupts using nothing but bare metal.
#STM32 #BareMetal #Tutorial #Timer #PWM #STM32World #CurrentMakers #Streamline
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Управление фазой аппаратного PWM сигнала на STM32
На микроконтроллерах STM32 можно генерировать аппаратные PWM сигналы. Это всегда применяют для регулирования яркости свечения, управления температурой нагревателей, управления крутящим моментом на моторах. При этом легко можно регулировать частоту, заполнение и инвертировать фазу меняя полярность. Однако как непрерывно регулировать фазу PWM?. В этом тексте я написал три способа управлять фазой PWM сигнала.
https://habr.com/ru/articles/1023940/
#pwm #stm32 #phase #pwm_phase #hw_pwm #pwm_hw #шим #masterslave #master #slave
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Polémica con el Galaxy S26 Ultra – Su función estrella «Privacy Display» está provocando fatiga ocular y dolores de cabeza
Lo que debía ser la innovación más aplaudida de Samsung para 2026 se está convirtiendo en su mayor dolor de cabeza, literalmente. A pocos días del lanzamiento oficial, una oleada de usuarios del Galaxy S26 Ultra ha comenzado a reportar fatiga ocular, náuseas y cefaleas tras usar el dispositivo. El culpable parece ser el nuevo panel «Privacy Display», una tecnología diseñada para ocultar el contenido de la pantalla a los curiosos, pero que está pasando factura a los ojos más sensibles (Fuente AndroidAuthority).
Esta controversia, se suma a una semana difícil para Samsung tras el error de certificación de Google Play que bloqueó apps bancarias en algunas unidades del S26.
El problema: PWM de baja frecuencia y «texto borroso»
Aunque Samsung promocionó el S26 Ultra como la cima de la ingeniería visual, los entusiastas de la tecnología han descubierto que la compañía sigue utilizando una frecuencia de PWM (modulación por ancho de pulsos) de solo 480Hz, muy por debajo de los estándares de salud ocular que ya ofrecen sus competidores chinos como Vivo u Oppo.
- Parpadeo invisible: Los usuarios sensibles al parpadeo de las pantallas OLED experimentan mareos similares a los de las gafas de VR, ya que el cerebro detecta el ciclo de encendido y apagado de los píxeles aunque el ojo no lo vea.
- Falta de nitidez: Se han viralizado fotos macro que comparan el S26 Ultra con el S25 Ultra, mostrando que el texto en el nuevo modelo parece «sucio» o difuminado. Esto se debe a la Black Matrix, la estructura física necesaria para que funcione el filtro de privacidad, que reduce la claridad de los bordes de las letras.
¿Es un fallo de hardware o de software?
Lo más preocupante para los compradores es que estas molestias ocurren incluso con la función de Privacy Display desactivada.
«Es como si estuvieras mirando la pantalla a través de una lente empañada», comentan usuarios en Reddit.
Dado que la capa de privacidad es una característica física del panel OLED, expertos como el filtrador Ice Universe sugieren que una actualización de software no podrá corregirlo por completo, aunque Samsung podría intentar mitigar el efecto aumentando el brillo artificialmente mediante un parche.
Confusión con los «10 bits»
Para empeorar las cosas, Samsung ha tenido que rectificar sus materiales de marketing. Aunque inicialmente se dijo que el S26 Ultra tenía un panel nativo de 10 bits (1.000 millones de colores), la empresa ha confirmado que se trata de un panel de 8 bits con FRC (una técnica que hace parpadear los píxeles para simular más colores). Este parpadeo adicional, sumado al bajo PWM, es la combinación perfecta para generar fatiga visual en sesiones largas.
La respuesta de Samsung
Ante la presión, Samsung ha declarado que está investigando los reportes, pero mantiene que la pantalla cumple con todos los estándares de seguridad vigentes. Mientras tanto, recomiendan a los usuarios activar el «Escudo de comodidad ocular» y evitar niveles de brillo extremadamente bajos en habitaciones oscuras.
Este «Display-gate» ocurre en un marzo de 2026 donde la industria está bajo la lupa: mientras Apple filtra su iPhone plegable sin pliegues, Samsung se enfrenta a críticas por una pantalla que, por intentar proteger la privacidad del usuario, ha terminado comprometiendo su bienestar.
#android #arielmcorg #ciberseguridad #DisplayGate #GalaxyS26Ultra #infosertec #innovación #pantalla #PORTADA #PWM #salud #Samsung #TechNews2026 #tecnología -
Micro Music Media Library (2019)
by @protodome
"This is the companion web page for the Micro Music: Exploring the Idiosyncratic Compositional Strategies Encountered in 1-Bit, Limited Memory Environments doctoral project. [...] 1-bit music, generally considered a sub-division of chiptune, is the music of a single square wave. [...] [T]he unique techniques and auditory tricks of contemporary 1-bit practice exploit the limits of human perception. Through layers of modulation, abstraction and clever writing, these compositional methods generate music far more complex than the medium would, at first impressions, indicate..."
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https://www.europesays.com/pl/118123/ Chieftec The Cube – tania obudowa mATX jak głośnik, która oferuje składaną konstrukcję i 200 mm wentylator. Specyfikacja i cena #chieftec #ChieftecTheCube #hdb #matx #microatx #MiniITX #Nauka #NaukaITechnika #NaukaTechnika #obudowa #PL #Poland #Polish #Polska #Polski #PWM #Science #ScienceAndTechnology #ScienceTechnology #specyfikacja #Technika #Technology
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The most literal LED lighting dimmer switch in the known universe. #pwm
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Обзор микросхемы DRV8870
DRV8870 - это старая простая микросхема управления коллекторным DC -мотором с токами в обмотках до 3.5 Ампер от компании Texas Instruments. По сути это драйвер H-моста . Причем H-мост встроен прямо внутрь корпуса самой микросхемы. Это полностью интегрированное решение. В этом тексте я произвел обзор микросхемы DRV8870. Посмотрим с какой стороны следует подходить к микросхеме DRV8870.
https://habr.com/ru/articles/952484/
#DRV8870 #hbridge #hмост #stm32 #DevEBoxSTM32F4XX_M_V30 #STM32F407VGT6 #pwm #TIMER #gpio #18650
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Simple PWM Filter PCB Build Guide
Here are the build notes for my Simple PWM Filter PCB Design. Below you can see it connected to my Pico Touch Board.
Warning! I strongly recommend using old or second hand equipment for your experiments. I am not responsible for any damage to expensive instruments!
If you are new to electronics and microcontrollers, see the Getting Started pages.
Bill of Materials
- PWM Audio Filter PCB (GitHub link below)
- 2x Suitable filter components, for example, per channel:
- 3x 1KΩ resistors
- 2x 100nF ceramic capacitor
- 1x 2u2 electrolytic capacitor
- Optional: Pin headers
- Optional: 2x 3.5mm TRS sockets (pcb mounted, see photos for footprint)
Build Steps
Taking a typical “low to high” soldering approach, this is the suggested order of assembly:
- All resistors.
- TRS sockets (if used).
- Disc capacitors.
- 3-way jumper headers (if used).
- Electrolytic capacitors.
Here are some build photos.
If the electrolytic capacitors will be bent over, then they should be bent and soldered in place before the header pins.
Testing
I recommend performing the general tests described here: PCBs.
PCB Errata
There are no known issues with this PCB at present.
Enhancements:
- As previously mentioned it might have been useful to label the left and right channels and use the alternative resistor circuit symbol.
- It might have been useful to include solder jumpers to allow the simple combining of the left and right inputs and outputs
- Some additional connection points for an oscilloscope might have been useful too.
Sample Applications
Here are some applications to get started with:
- Pico Touch Board Audio – 3x 1K resistors, 3x 100nF capacitors, and 1x 2u2 electrolytic per channel.
Experimenter board
Rather than fixed components, it is possible to solder on round pin header sockets to allow components to be pushed into place. This means that it is fairly easy to experiment with alternative component values to see what difference they make.
When doing this, I only soldered up one channel, but joined the left/right inputs and outputs by adding a solder bridge across the pin headers. I also soldered additional pins to the spare GND connections from the second channel. This allows plenty of pin connections for an oscilloscope.
The connections for components aren’t as tight as they could be, especially for low-wattage components with pretty thin legs.
It might be that just continuing to use solderless breadboard for experiments is simpler, but it was pretty useful to be able to leave oscilloscope connections and the input and output connected whilst experimenting.
Board Manufacturing
These boards are sized to allow them to be ordered in a 2×4 panel if required, and still remain within a 100x100mm footprint. I used jlcpcb’s panel options with v-cuts and it was really quite inexpensive to do.
Closing Thoughts
I’m still not sure I really understand enough analog electronics to get the theory of how a dual-stage filter incorporating a potential divider still works, and any simulation is still not quite matching my theory to experiment.
As has been said, “in theory, theory and practice are the same, in practice they are different”.
This might make some proper practicing a bit easier.
Kevin
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Simple PWM Filter PCB Design
Having spent a bit of time attempting (although I’m not sure I’m succeeding yet) to understand how to get a useful filter for my Pico Touch Board Audio, I thought it would be useful to have a simple template PCB that could be used for a range of PWM low-pass filtering options.
This is my design.
Warning! I strongly recommend using old or second hand equipment for your experiments. I am not responsible for any damage to expensive instruments!
If you are new to electronics and microcontrollers, see the Getting Started pages.
The Circuit
This is following on from the discussion in Pico Touch Board Audio creating the template for a simple two-stage low-pass filter with an option for including a potential divider resistor to drop the overall voltage too.
I’ve doubled the circuit to allow for stereo in and out if required and have included both 3.5mm TRS sockets and pin jumper headers for both input and output.
It requires no power, being a completely passive filter.
If stereo is not required, then just one of the circuits can be populated – ideally the one connected to the TRS tip.
PCB Design
There isn’t much to this pcb layout really. I was particularly keen to keep the PCB away from specific values of components, so instead used the silkscreen to present a pseudo-circuit diagram to make it clear which components are which.
I’ve also tried to leave enough room for the electrolytic capacitors to allow them to be bent over if required.
Closing Thoughts
With hindsight, I can think of a couple of additions that would have been useful on the silkscreen – labelling which circuit is left and right for example.
And having the boards back, I should have added manual “wavy line” resistor diagrams rather than rectangles, but it is enough for what I need.
And it might have been useful to include some additional test points for connecting an oscilloscope.
Kevin
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STM32 Tutorial #65 - Bit Banging PWM SUPER Optimized
In this Tutorial video we will dive further into timers by using a timer to bit bang PWM on a GPIO where no timer channel is available (such as PC13). We will begin by letting STM32CubeMX generate all the code but then optimize that by creating our own interrupt handler.
#STM32 #GettingStarted #Tutorial #STM32CubeIDE #STM32CubeMX #Timer #PWM #BitBang #STM32World
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Converting a Sprinkler System to DC https://hackaday.com/2025/08/22/converting-a-sprinkler-system-to-dc/ #greenhacks #conversion #sprinkler #solenoid #drv103 #grass #lawn #pwm #ac #dc
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Converting a Sprinkler System to DC - Famously, Nikola Tesla won the War of the Currents in the early days of electrific... - https://hackaday.com/2025/08/22/converting-a-sprinkler-system-to-dc/ #greenhacks #conversion #sprinkler #solenoid #drv103 #grass #lawn #pwm #ac #dc
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I just found this blog post about how to make #music using #pwm on #lego #powerfunctions #motors. not that I want to, but there is quite some technical information in there.
Gets me thinking about building a simple #train motor Forth library. To run on a microcontroller inside your #locomotive to which you connect via wifi ... hmmm ... @f4grx what do you think?!
https://brickexperimentchannel.wordpress.com/2023/05/06/music-with-lego-motors-pwm/
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A Repeater for WWVB - For those living in the continental US who, for whatever reason, don’t have access... - https://hackaday.com/2025/08/07/a-repeater-for-wwvb/ #clockhacks #wristwatch #amplifier #arduino #clock #radio #watch #wwvb #pwm
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Pico Touch Board Audio
I wanted to go back to my Pico Touch Board PCB Design and see if there was a way to make it more stand-alone. The original design was to make it a MIDI controller, but that isn’t the only option.
https://makertube.net/w/tADSyrPrUdR1mx7yKRXZTC
Warning! I strongly recommend using old or second hand equipment for your experiments. I am not responsible for any damage to expensive instruments!
These are the key Arduino tutorials for the main concepts used in this project:
If you are new to microcontrollers, see the Getting Started pages.
Parts list
- Pico Touch Board PCB – built
- Resistors: 1x 220Ω, 1x 1K
- Capacitor: 1x 100nF ceramic, 1x 22uF electrolytic
- Breadboard and jumper wires
The Circuit
Most of the GPIO are linked out to the touch pads, but the three analog inputs are still available. They are added on to the header on the right hand side of the board at the top, so we can use one of these as an audio output.
Initially, I thought of connecting it to an 8Ω speaker. If I was using an Arduino then I’d use a 220Ω resistor in series to limit the current to less than 20mA. But as I’m using a Pico, the maximum current has to be a lot less. I seem to recall it is a little complicated, and there are some options, but I have a figure of around 4mA that I tend to work to. It is also running at 3.3V, which means that it would need an in series resistor of 3.3 / 0.004 = 825Ω. This would work, but the speaker will be really quiet!
So I ditched that idea (there is a software reason too, but I’ll talk about that in a moment) and went straight to a PWM output with a low-pass filter to try to give me some vaguely useful as a line-out signal.
I’ve not done the calculations, but instead went a bit “hand-wavy”, combing a 1K and 220Ω resistor to drop the voltage, along with a 100nF capacitor. I’ve also added a 22uF capacitor to remove the DC bias.
That seems to give me something useful, but as you can see from the trace below of a square wave PWM output, there is a lot of room for improvement!
Update
Ok, so going back and doing this semi-properly as per my notes from Arduino PWM Output Filter Circuit, I can see that the 1K and 220Ω resistors can be treated as a 180Ω equivalent (take them as two in parallel) for the filter circuit, which means a cut-off of around 8kHz which ought to be pretty good….
But reducing a 3V3 signal to around 20% leaves for quite a low level of audio – around 660mV peak to peak. It would probably be better to aim for a reduction of around a half.
Using a 1K and 500Ω resistor would be an equivalent resistance of 333Ω, so putting that into a low pass filter calculator gives a cut-off frequency of around 5kHz for a 100nF capacitor.
Weirdly the only thing that really seems to improve things is to raise that capacitor value to 1uF. My calculation would suggest a cut-off frequency of around 480Hz which is pretty small for an audio signal. But it seems to work.
The PWM frequency I was seeing was coming in at around 120kHz so should be plenty high enough to get filtered out. In the Circuitpython code, it is apparently chosen to support the number of bits required at the base clock frequency whilst being inaudible. For the RP2040 running at 125MHz, and with the chosen 10 bit resolution (more here) this is:
- 125,000,000 / 1024 = 122,070 Hz
A 5kHz (or even 8kHz) cut-off I thought ought to be fine, but Davide Bucci on Mastodon explained for me:
“120kHz is 25 times 4.7kHz, that is about 1.4 decades and with a first-order filter you have a tad less than 30dB of attenuation, that is not a lot. A signal at 3.3V peak to peak at 120kHz becomes about 100 mV on the output after the filter.”
So switching to 1uF, as Davide explains: “if you put 1µF, you are indeed filtering a decade lower, therefore you gain 20dB in the attenuation and the 100mV become 10mV, much less noticeable.”
The alternative is to repeat the 1K+100nF stage and add a second order filter which also seems to work pretty well.
The final circuit that works fine for me at present, will be on of the following.
The first is less components but assumes that the frequencies won’t go much about ~1KHz or so. That is ok for my current setup but would limit the audio range a fair bit.
This is the output of the two-stage filter. It is so much better!
The Code
I wanted to stick with Circuitpython, so my initial thought was to use simpleio.tone() to generate a tone based on a frequency from an IO pin. However, this has the problem that the code is blocking whilst the tone is playing which isn’t very useful.
Instead I went straight to synthio. It turns out that using synthio was actually a lot easier than the “simple” simpleio…
Here is the basic code to generate an ASR-shaped square wave on a PWM audio output on GPIO 28 based on the touch pads as input.
import board
import touchio
import synthio
import audiopwmio
from adafruit_debouncer import Debouncer, Button
audio = audiopwmio.PWMAudioOut(board.GP28)
synth = synthio.Synthesizer(sample_rate=22050)
audio.play(synth)
synth.envelope = synthio.Envelope(attack_time=0.1, release_time=0.6, sustain_level=1.0)
touchpins = [
board.GP2, board.GP3, board.GP4, board.GP5,
board.GP6, board.GP7, board.GP8, board.GP9,
board.GP10, board.GP11, board.GP12, board.GP13,
board.GP14, board.GP15, board.GP16, board.GP17,
board.GP18, board.GP19, board.GP20, board.GP21, board.GP22
]
THRESHOLD = 1000
touchpads = []
for pin in touchpins:
t = touchio.TouchIn(pin)
t.threshold = t.raw_value + THRESHOLD
touchpads.append(Button(t, value_when_pressed=True))
while True:
for i in range (len(touchpads)):
t = touchpads[i]
t.update()
if t.rose:
synth.press(60+i)
if t.fell:
synth.release(60+i)I did experiment with overclocking the Pico to give double the PWM frequency, using
microcontroller.cpu.frequency = 250_000_000
But although this did double the PWM frequency to around 244kHz, it didn’t seem to make much difference for the filtered signal.
Battery Power
One last thing I wanted to explore was if it was possible to power the touchboard with batteries. I left in a number of power options, so for this one I’m using the 5V/GND pin header. I’ve included a couple of capacitors for smoothing, and need to add the 1N5817 diode as shown below.
This requires the following additional components:
- 1x 1N5817 Schottky diode.
- 1x 100nF ceramic capacitor.
- 1x 47uF electrolytic capacitor.
- Jumper wires.
- 3 or 4 battery box.
The 5V/GND header pins connect to the Raspberry Pi Pico’s VSYS pin via the Schottky diode. The 1N5817 has a typical voltage drop of 0.45V, so combined with the Raspberry Pi’s accepted input voltage of 1.8V to 5.5V this means that ideally two or three AA batteries (at 1.5V each) would work. Four 1.2V rechargeables might be an option too.
It might be possible to get away with four 1.5V AAs, but that would give an input voltage of just over 5.5V, so I think that is probably pushing things too far. It might be a good use for some spent AAs though that are no longer reading a full 1.5V…
One of the downsides of battery power is that the touch works best when your fingers are at the same GND potential as the board. It works best if the GND pin of the (unpopulated) barrel jack is touched when using the board.
Closing Thoughts
With hindsight it would have been useful to have included a simple PWM output stage on the original board, but it is relatively straight forward to add one.
It might even be worth me making an add-on board that will connect to the header pins of the power and analog pins containing the simple passive filter components.
What is pretty impressive though, is how easy it is to use synthio with Circuitpython.
Kevin
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Show HN: My GPU Fan Saga – A DIY ATX Fan Controller
https://shafq.at/my-gpu-fan-saga.html
#ycombinator #firmware #hardware #tech #pwm #attiny85 #fan -
Timer Input Capture
In this video we'll be revisiting timers. In a much earlier video we were using Timer Input Capture to decode rotary encoders. In this video we will be using input capture mode to measure frequency and duty cycle of a pulse width moduleated input.
#STM32 #GettingStarted #Tutorial #STM32CubeIDE #STM32CubeMX #PWM #Timer #InputCapture #STM32World
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Portland International Jetport - Portland, United States
https://en.wikipedia.org/wiki/Portland_International_Jetport
https://www.openstreetmap.org/#map=13/43.646198/-70.309303#KPWM #PWM #Portland #UnitedStates #airport #aviation #avgeeks #GIS
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Разработка больших цифровых часов на светодиодной ленте
Когда-то давно в детстве, когда я ещё только начинал заниматься электроникой, у меня была мечта изготовить огромные часы на семисегментных индикаторах. Для их изготовления я рассматривал люминесцентные лампы дневного света. По прошествии многих лет в обиход вошли светодиодные ленты. Именно они и послужили стимулом воплотить свою старую задумку в реальность. Имея возможность и опыт программирования микроконтроллеров, я решил, конечно же, самостоятельно изготовить электронную плату для часов со своими функциональными возможностями. В данной статье я не буду подробно описывать принципиальную схему и прошивку МК. Напишу лишь краткий обзор и историю разработки своей конструкции.
https://habr.com/ru/articles/844440/
#atmega8 #atmega32 #часы #светодиодная_лента #pwm #шим #tcp/ip #rs232 #ds3231 #bmp280
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Homebrew Reader Brings Paper Tape Programs Back to Life https://hackaday.com/2024/06/15/homebrew-reader-brings-paper-tape-programs-back-to-life/ #phototransistor #Retrocomputing #altair8800 #papertape #simulator #terminal #Wedge #pwm
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Homebrew Reader Brings Paper Tape Programs Back to Life - We may be a bit biased, but the storage media of yesteryear has so much more perso... - https://hackaday.com/2024/06/15/homebrew-reader-brings-paper-tape-programs-back-to-life/ #phototransistor #retrocomputing #altair8800 #papertape #simulator #terminal #wedge #pwm
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Arduino Audio and MIDI Frameworks
I’ve been collecting bookmarks for interesting Arduino audio projects for a while now, and having now played with the XIAO SAMD21 I started looking back over my list for other things to try. One thing that occurred to me is that there are a now a number of more powerful audio frameworks available for a range of microcontrollers, so in this post I’m doing an introductory “look see” at some of them, largely as “notes to self” to come back to them for some more detailed projects in the future.
Note: Many of these require a 32-bit processor, which is one of the reasons I’ve not looked at them so far.
Warning! I strongly recommend using old or second hand equipment for your experiments. I am not responsible for any damage to expensive instruments!
If you are new to microcontrollers, see the Getting Started pages.
Mozzi
I’ve spent quite a bit of time with Mozzi of course, the synthesis library for Arduino that supports a large range of microcontrollers, including the “original” 8-bit Arduino ATmega328P, so I won’t go over that again here.
For a starting point with Mozzi, see: Arduino PWM MIDI Synthesis with Mozzi. For using Mozzi on a 32-bit SAMD processor, there is more here and here.
But Mozzi isn’t the only game in town, especially if we’re expanding out to 32-bit microcontrollers.
The Arduino Sound Library
https://www.arduino.cc/reference/en/libraries/arduinosound/
This is an official Arduino library that supports SAMD21 based microcontrollers using an I2S digital to analog converter. It is designed for the MKR series of official Arduino boards.
Interestingly it appears to only support I2S audio devices for sound input and output. That seems like a little bit of a missed opportunity to me in that the SAMD21 has a built-in DAC, but I guess analogWrite() deals with access to the DAC relatively easily.
It is designed for official Arduino SAMD architecture boards – so those in the MKR series. It might work on other SAMD architecture boards, I haven’t looked into it in detail.
Phil Schatzmann’s Arduino Audio Tools
https://github.com/pschatzmann/arduino-audio-tools
This is a suite of open source code for audio stream processing, providing a range of audio sources (e.g. microphones, Internet streams, files, sensors, and so on) and sinks (e.g. DACs, PWM audio, MP3, codecs, audio modules, etc).
It can be used to build audio players, processors, effects, file processors, audio visualisers, networked audio tools, and so on.
I believe it supports the following microcontroller architectures:
- ESP32 (S and C variants)
- ESP8266
- RP2040 (MBED and non-MBED)
- AVR
- STM32
- SAMD
It supports several audio output boards too, including: ESP32-A1S based boards (ES8388 or AC101 codecs); VS1053 modules; and WM8960 modules.
I believe this is a library for audio processing, not necessarily audio synthesis.
Marcel Licence’s ML Synth Tools
https://github.com/marcel-licence/ML_SynthTools
This is a comprehensive synth library for producing synthesizers, organs and effects. Most of the code is open source, but there are certain key elements that are provided only in pre-built library form.
It provides libraries for the following microcontrollers:
- ESP32
- ESP8266
- XIAO SAMD21
- Teensy 4.1
- Daisy Seed
- Raspberry Pi Pico RP2040
- STM32F407
As well as the synthesizer core oscillators there are modules for arpeggiators, effects, meters, scopes, and MIDI file playing. Here are some example builds using the library:
- ML Organ (all platforms): https://github.com/marcel-licence/ml_synth_organ_example
- SAMD21 Synth: https://github.com/marcel-licence/samd21_mini_synth
- ML Synth (all platforms): https://github.com/marcel-licence/ml_synth_basic_example
- ESP32 FM synth: https://github.com/marcel-licence/esp32_fm_synth
- ESP32/RP2040 e-piano: https://github.com/marcel-licence/ml_epiano_example
Although it isn’t fully open source, this non-the-less looks like it would be worth taking a more detailed look. The provided videos of Marcel playing are particularly excellent.
MIDI Controller Libraries
There are a number of Arduino libraries for building MIDI controllers. Here are a selection of some that I’ve found so far.
OpenDesk MIDI Platform – https://github.com/shanteacontrols/OpenDeck
This is a set of firmware and two official PCB designs for MIDI controllers. In addition to the official boards, it also supports many microcontrollers, including:
- Arduino Mega 2560
- Arduino Nano 33 BLE
- Raspberry Pi Pico
- XIAO RP2040
- Teensy++ 2.0
And many others. It includes a web-based configuration utility for defining the MIDI commands for the controls. Official boards are available on Tindie and you can read more about them here: https://shanteacontrols.com/.
It supports a range of buttons, encoders, potentiometers, force sensitive resistors, certain touchscreens and can provided feedback using LEDs and displays.
Control Surface – https://github.com/tttapa/Control-Surface
This is a general purpose library for building MIDI input and output control devices. It supports a wide range of microcontrollers, including:
- AVR (Uno, Mega, Leonardo).
- Arduino Nano Every and 33.
- Teensy.
- ESP8266
- ESP32
- Raspberry Pi Pico
It supports a range of MIDI transports, including serial, USB, “direct serial” (using Hairless MIDI) and MIDI BLE. It also supports a range of buttons, potentiometers, rotary encoders, switches, keyboard matrices, and so on and can provide visual feedback using a range of LEDS and displays. It has built-in support for multiplexers, shift registers and LED drivers.
It includes a huge number of example projects to browse.
MIDIPal – https://github.com/pichenettes/midipal
This is a “MIDI Swiss Army Knife” that, with the additional of a display and rotary encoder, can provide a wide range of MIDI processing functions. It includes an editor application for programming MIDI filters.
This is a “native” AVR application, not for the Arduino environment.
Notes and Volts MIDI Controller – https://www.notesandvolts.com/2016/04/arduino-midi-controller-buttons.html
This is provided for completeness as it is a fairly common codebase for people to find and use with an Arduino. It supports a range of potentiometers and buttons and makes the task of configuring them as a MIDI control device relatively straight forward.
Closing Thoughts
As I say, this post is really almost a bit of a “to-do list” of things that look interesting and that I might try to take a more detailed look at, at some point.
If you have experience of any of these frameworks or libraries; or have suggestions of others that might be worth a look, do let me know in the comments!
Kevin
#ArduinoAudioTools #ControlSurface #dac #esp32 #fmSynthesis #i2s #midi #midiController #MIDIPal #MLSynthTools #mozzi #OpenDesk #pwm #rp2040 #samd21 #synthesis #xiao
