MOD2 Prototype test | Seeed XIAO RP2350 based Drum module for eurorack

video upload by HAGIWO

":Almost all of the programs were generated by ChatGPT.
Since the circuit has been simplified, there are few CV inputs and the audio is output via PWM, but the RP2350 is fast enough that even a simple program can produce reasonably good sound.

Although there are no plans to use it as a VCO, it also supports V/oct.
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Repository of HAGIWO's DIY Modular Synth
https://note.com/solder_state/n/n54e0..."

DIY eurorack modular synth | MOD1 Square VCO & 3ch LFO : Arduino based general-purpose module

video upload by HAGIWO

"This module is an open source general-purpose CV/Gate module based on Arduino nano. It can be applied to various CV/Gate modules by changing the program. There are some performance limitations, but it uses general-purpose inexpensive components.

Square VCO:
Audio output operation is somewhat unstable and produces a noise sound.

Square wave oscillator with V/oct support.
LFO for vibrato and octave like chiptune.
The capacitor in the D11 output circuit needs to be removed."

DIY eurorack modular synth | MOD1 3ch LFO : Arduino based general-purpose module

video upload by HAGIWO

"This module is an open source general-purpose CV/Gate module based on Arduino nano.
It can be applied to various CV/Gate modules by changing the program.
There are some performance limitations, but it uses general-purpose inexpensive components.

3ch LFO :
1 CV in , 3 CV out.3 waveform."

DIY eurorack modular synth | MOD1 Clock sync Trigger burst : Arduino based general-purpose module

video upload by HAGIWO

"This module is an open source general-purpose CV/Gate module based on Arduino nano.
It can be applied to various CV/Gate modules by changing the program.
There are some performance limitations, but it uses general-purpose inexpensive components.

Clock sync Trig burst :
When POT3 is turned fully left, it accepts an external clock for F1.
When POT3 is to the right of 9:00, it switches to the internal clock.
The internal clock can be adjusted with POT3.

working documents
https://note.com/solder_state/n/nc05d...
https://note.com/solder_state/n/n59f6...

PCB gerber data & PCB assy production data Download
https://www.patreon.com/posts/mod1-ar..."

DIY eurorack modular synth | MOD1 Random CV sequencer : Arduino based general-purpose CV/Gate

video upload by HAGIWO

"This module is an open source general-purpose CV/Gate module based on Arduino nano.
It can be applied to various CV/Gate modules by changing the program.
There are some performance limitations, but it uses general-purpose inexpensive components.

Random CV sequencer : Periodic random CV sequencer.

working documents
https://note.com/solder_state/n/nc05d...
https://note.com/solder_state/n/nd2af...

PCB gerber data & PCB assy production data Download
https://www.patreon.com/posts/mod1-ar...

Please support me to continue projects."

DIY eurorack modular synth | MOD1 Tap tempo clock : Arduino based general-purpose CV/Gate module

video upload by HAGIWO

"This module is an open source general-purpose CV/Gate module based on Arduino nano.
It can be applied to various CV/Gate modules by changing the program.
There are some performance limitations, but it uses general-purpose inexpensive components.

Tap tempo clock : 4-output tap tempo master clock.
Four outputs: 4x fixed output, 1~16x variable output, and two variable 1~/16 division outputs.

working documents
https://note.com/solder_state/n/nc05d...
https://note.com/solder_state/n/nf004...

PCB gerber data & PCB assy production data Download
https://www.patreon.com/posts/mod1-ar..."

DIY eurorack modular synth | MOD1 Envelope generator : Arduino based general-purpose CV/Gate

video upload by HAGIWO

"This module is an open source general-purpose CV/Gate module based on Arduino nano.
It can be applied to various CV/Gate modules by changing the program.
There are some performance limitations, but it uses general-purpose inexpensive components.

Envelope generator : 3-output EG. end-of-cycle outputs can be self-patched for use as LFO or clock

working documents
https://note.com/solder_state/n/nc05d...
https://note.com/solder_state/n/n7499...

PCB gerber data & PCB assy production data Download
https://www.patreon.com/posts/mod1-ar..."

DIY eurorack modular synth | MOD1 Euclidean sequencer : Arduino based general-purpose CV/Gate

video upload by HAGIWO

"This module is an open source general-purpose CV/Gate module based on Arduino nano.
It can be applied to various CV/Gate modules by changing the program.
There are some performance limitations, but it uses general-purpose inexpensive components.

Euclidean sequencer: 8step or 16step sequencer. Adjustable output probability and number of hits.

working documents
https://note.com/solder_state/n/nc05d...
https://note.com/solder_state/n/n4284...

PCB gerber data & PCB assy production data Download
https://www.patreon.com/posts/mod1-ar..."

DIY eurorack modular synth | MOD1 LFO : Arduino nano-based general-purpose CV/Gate module

video upload by HAGIWO

"This module is an open source general-purpose CV/Gate module based on Arduino nano.
It can be applied to various CV/Gate modules by changing the program.
There are some performance limitations, but it uses general-purpose inexpensive components.

LFO: 3CV in - 1CV out simple LFO.

working documents
https://note.com/solder_state/n/nc05d...
https://note.com/solder_state/n/ne91e...

PCB gerber data & PCB assy production data Download
https://www.patreon.com/posts/mod1-ar..."

[$18] DIY eurorack modular synth 山景DSP FX Pitch Shifter & Reverb | BP1032 based

video upload by HAGIWO

"My 84th original eurorack modular synth DIY projects.
BP1032 DSP Reverb module from China based FX module.
Effect types and parameters can be changed using PC software called APCWrokbench.

working documents (schematics)
https://note.com/solder_state/n/nba86...

Sound test videos for other effects and parameter changes (patreon)
https://www.patreon.com/posts/shan-ji...

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Repository of HAGIWO's DIY Modular Synth
https://note.com/solder_state/n/n54e0..."

Module description, Google translated:

Background
The 84th work of my own modular synth.
There are many suspicious circuit modules on sale on Aliexpress whose purpose is unknown.
Depending on your idea, you can easily create original modules at low cost.
This time, I planned to create a Pitch Shifter using such a suspicious and attractive Chinese module.

Pitch shifter
A pitch shifter is a type of effect that raises or lowers the frequency of the input sound. By layering 5th or octave sounds, you can create a thick sound.
There are also several Pitch shifter modules on the market for modular synths.

Specifications of the work
Eurorack standard 3U 8HP size
Power supply: 50mA (+12V), 10mA (-12V)

Pitch shifter module using BP1032 DSP IC manufactured by Mountain View Silicon, a Chinese semiconductor manufacturer.
The amount of pitch shift is fixed. In my case, I use it at a perfect fifth (5th).

DRY POT: Adjusts the DRY volume
WET POT: Adjusts the WET volume
INPUT LEVEL: Adjusts the input signal. Adjusts the input level to accommodate ±5V of modular synth sound and general line level.
OUTPUT LEVEL: Adjusts the output volume
Signal IN: Audio input
L Out: Left output. Not used with Pitch shift, but valid when the Reverb effect is selected.
R Out: Right output. Not used with Pitch shift, but valid when the Reverb effect is selected.
The biggest drawback of this module is that it does not have an interface for the applied effects or effect parameters on the front panel.
You can adjust the effects and parameters by connecting it to a PC via USB C.
In addition to being a pitch shifter, it can also be used as a reverb or delay depending on the settings.
ACPWorkbench
To switch effects, use PC software called ACPWorkbench.
This software is made in China and is of questionable origin, so use at your own risk. My PC's antivirus software did not detect any viruses, but I don't know if it's safe.

[$9] DIY eurorack modular synth Arduino Unison VCO w/ Seeed XIAO RA4M1

video upload by HAGIWO

"My 83rd original eurorack modular synth DIY projects.
Seeed XIAO RA4M1 based Dual Oscillator VCO.
You can create a thick sound by using detune or adding a 5th.

working documents (schematics , code)
https://note.com/solder_state/n/na0ae...

Python program for wavetable generation , Additive , FM and PWM duty. / 114675733

Seeed XIAO RA4M1
https://www.seeedstudio.com/Seeed-XIA..."

"Specifications

Eurorack standard 3U 6HP size

Power supply: 10mA (±12V), 20mA (5V)

2-oscillator digital VCO using Seeed XIAO RA4M1.

Supports V/oct, and the waveform can be selected from 16 types of wavetable.

The frequencies of OSC1 and OSC2 are always in a relative position relationship, and detune and overtones can be added by shifting the frequency of OSC2.

OSC1 FREQ POT: Adjusts the reference frequency of OSC1 and OSC2
OSC2 FREQ POT: Adjusts the frequency of OSC2 relative to OSC1. Can be set from 0 oct to 2 octs above.
OSC2 volume POT: Adjusts the volume of OSC2
OSC2 volume CV in: CV input for adjusting the volume of OSC2
Wave push SW: Selects the wavetable. 16 types in total.
V/oct IN: V/oct input, range is 0~5V.
OUT: Audio output, range is Vpp10V.

The selected waveform information is stored in EEPROM. When the power is turned on again, the last selected waveform is selected."

Seeed studio XIAO RA4M1 simple Arduino synthesizer : VCO for eurorack modular synth

video upload by HAGIWO

"Modular synthesizer VCO. using Seeed studio XIAO RA4M1.
Supports V/oct and audio output via built-in DAC.
This is an improved version of the UNO R4 VCO created in the past."

https://note.com/solder_state/n/n76a6b0a4a5d6

[$5] DIY eurorack modular synth Low pass gate for percussin | with cheap vactrol made in China

video upload by HAGIWO

"My 82nd original eurorack modular synth DIY projects.
Low pass gate for percussion sound.
Cheap, mass-produced vactrol LCR-0203 from China is used.

working documents (schematics)
https://note.com/solder_state/n/n4f1f...

Comparison of Attenuation Characteristic Curves for vactrol made in China
/ 109954005

Please support me to continue projects.
In patreon you will find content about my background , technical information. / hagiwo

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Repository of HAGIWO's DIY Modular Synth
https://note.com/solder_state/n/n54e0..."

DIY modular synth jam #9 | Practice techno with the Arturia BeatStep Pro

video upload by HAGIWO

"Yeah, I definitely need more practice with playing, but I can't help it because building modules is just so much more fun."

Repository of HAGIWO's DIY Modular Synth

[$11] DIY eurorack modular synth SSI2131 VCO | analog oscillator

video upload by HAGIWO

"My 79th original eurorack modular synth DIY projects.
SSI2131 IC based analog VCO.

working documents (schematics)
https://note.com/solder_state/n/nf478...

Additional information about SSI2131 VCO module
https://www.patreon.com/posts/1054345...

Please support me to continue projects.
In patreon you will find content about my background , technical information.
https://www.patreon.com/hagiwo"

[$9] DIY eurorack modular synth opto compressor | vactrol type optical compressor

video upload by HAGIWO

"My 78th original eurorack modular synth DIY projects.
LCD-0203 based opto compressor.

working documents (schematics)
https://note.com/solder_state/n/n60c2...

Gerber data download (Envelope follower PCB module)
https://www.patreon.com/posts/1036574...

Please support me to continue projects.
In patreon you will find content about my background , technical information. / hagiwo"

Google translated:

background
The 78th work of my own modular synth.
One of Eurorack's standard modules is MATHS. One of the uses of MATHS is Envelope follower, but this Envelope follower is difficult to use properly.
I have created an Envelope follower in the past. This time, I decided to create a compressor as one of the application examples of Envelope follower.

Opto compressor
Compressors include VCA and FET as means of compressing audio, but there is also a type called opto compressor that uses Vactrol (analog photocoupler).
Although the responsiveness is poor, we decided to create an opto compressor this time because it can be created inexpensively with few parts.

Product specifications
Eurorack standard 3U 6HP size
Power supply: 20mA (+12V), 20mA (-12V)

opto compressor using Vactrol LCR-0203.
The idea is to use it to increase the sound pressure by compressing the entire MIXed audio, or to change the impression of the sound by compressing a single percussion sound such as KICK.

THRESHOLD: Adjustment of the level at which compression starts.
RATIO: Attenuation rate adjustment. By increasing RATIO, it is possible to compress at a magnification of 1x or less. In other words, the louder the input audio, the lower the output can be.
RELEASE: Adjust the RELEASE TIME of the built-in Envelope follower.
VOLUME: Audio out amplification. Lowering the THRESHOLD lowers the overall volume, so the VOLUME POT compensates for the volume drop.
LED: The more compresson is applied, the brighter the light will light up.
Also used for calibration.
IN: Audio input. It is assumed to be used at Vpp=10V (-5V~+5V).
OUT: Audio out

Production cost
Total about $9
---------------------------------
LCR-0203 $1
Front panel $1
Envelope follower module $2
Variable resistance $0.3*4pcs
Others (see link below for general purpose parts)

[$11] DIY eurorack modular synth SSI2140 VCF | 4pole Low Pass Filter

video upload by HAGIWO

"My 77th original eurorack modular synth DIY projects.
4 pole low pass filter based on SSI2140 VCF IC.

working documents (schematics)
https://note.com/solder_state/n/n9fd3...

Study of SSI2140 Q VCA function (patreon)
Video of waveforms when tuning the resistance of the SSI2140 Q VCA.
https://www.patreon.com/posts/study-o..."

[$25] DIY eurorack modular synth Hard/Soft SYNC VCO with Arduino uno R4 , digital VCO

video upload by HAGIWO

"My 76th original eurorack modular synth DIY projects.
Arduino UNO R4 based digital VCO , it has Hard/Soft SYNC function.
Since the SYNC frequency is controlled by CV, SYNC sound can be created with fewer modules.

working documents ( code & schematics)
https://note.com/solder_state/n/n79d1..."

[Prototype] Arduino UNO R4 synthesizer : modular synth simple VCO

video upload by HAGIWO

"Modular synthesizer VCO. using Arduino uno r4 for technical verification.
Supports V/oct and audio output via built-in DAC.
Since this is a verification circuit, it is not recommended to make a module with this circuit as it is.

working documents ( schematics & code)
https://note.com/solder_state/n/na5ab..."

[$5] DIY eurorack modular synth Dual Slew Limiter

video upload by HAGIWO

"My 74th original eurorack modular synth DIY projects.
Dual Slew limiter , I aimed for simple functionality with few components.

working documents ( schematics)
https://note.com/solder_state/n/n09b1...

Please support me to continue projects.
In patreon you will find content about my background , technical information and CAD data.
https://www.patreon.com/hagiwo"

Description (Google translated):

The 75th work of my own modular synth.
One of the most basic modules of a modular synth is the Slew Limiter. Eurorack's most popular module, Make noise Maths, also has this slew limiter function.

I have also created modules with Slew limter functionality, but since I have never created a Slew limiter itself, I decided to create one.

Product specifications
Eurorack standard 3U 6HP size
Power supply: 15mA (+12V), 15mA (-12V)

Dual Slew Limiter with two types of functions.
Priority is given to low price and fewer parts.

top of module
Slew Limiter allows you to select the slew rate range from three types.
Select 3 types of range with the toggle switch.
L range: Assumed to be used for slow CV such as LFO
M range: Assuming the use of pitch CV portamento
S range: Assumes the use of an audio frequency low-pass filter
Control the slew rate with Pot.

Supports bipolar input.
Since the accuracy of the output voltage with respect to the input voltage is high, it can be used for V/oct pitch CV.

module bottom
Slew Limiter allows you to set Rise and Fall slew rates individually.
It is assumed that ASR envelope generator will be used.

Supports bipolar input.
Due to the circuit, the accuracy of the output voltage with respect to the input voltage is low. The use of V/oct pitch CV is not assumed.

Hagiwo's 9$ DIY Chord VCO v2

[ $9 ] DIY eurorack modular synth CHORD VCO v2 with Seeed XIAO RP2040 | Raspberry pie pico

video upload by HAGIWO

"My 61th original eurorack modular synth DIY projects.
RP2040 based 5 polyphonic CHORD VCO , easy to play chord progression.
Built-in quantizer and autoharmonics.

working documents ( schematics & source code )
https://note.com/solder_state/n/n64b9..."