minivolumidi Project

minivolumidi is a simple midi controller via wifi and rtpMIDI / apple network MIDI, based on a Wemos D1 mini (ESP8266) and a KY-40 rotary encoder that is intended to act as a volume controller. By default a short button press sets the CC value to the configured MIN_POS and a long button press sets it back to the value before the short button press.

This project is based on the following sources:

• https://github.com/lathoub/Arduino-AppleMIDI-Library/tree/master/examples
• https://github.com/LennartHennigs/ESPRotary/tree/master/examples
• https://github.com/FortySevenEffects/arduino_midi_library/tree/master/examples
• https://www.thingiverse.com/thing:2814909
• https://www.thingiverse.com/thing:3646462

Thanks to all the nice people making qick projects like this possible by their contributions to the open source world!

(more pictures in the img folder)

prerequirements for building the hardware

• Wemos D1 mini (ESP8266)
• a micro usb cable
• a KY-40 rotary encoder
• some wires
• soldering iron
• a 3d printer (if you want to print the case for it)
• hot glue gun

prerequirements for building the software

• install Platformio Core or Platformio IDE (which installes Pio core automatically)
• clone this repository

git clone https://github.com/Apfelwurm/minivolumidi.git

build (Visual Studio Code)

• open the cloned repo in VSCode

code minivolumidi

• open the src/main.cpp file and adapt the values in the configure section according to your requirements.
• open the platformio.ini file and change the upload_port to your needs (most likely /dev/ttyUSB0 on linux and COM3 on windows)
• Press f5 to build it.
• Press the PlatformIO:Upload button at the bottom navigation of vscode to flash your wemos d1.

build (CLI)

You can instead go to the repo folder with your terminal and run

pio run

respectively

pio run -t upload

depending if you want to just build or directly upload it to your wemos d1.

enclosure

You can find a 3d printable enclosure and the rotary encoder knob files in the case subdirectory. To print everything you can just use the case/wemos_stack_with_rotary_knob.stl in your favorite slicer. For customizing of the case or if you dont want to print the knob, look into the case/wemos_stack.scad and adjust it to your needs.

building the hardware

• print your case
• flash your Wemos d1
• bend the pins on your KY-40 rotary encoder so they face in the opposite direction as the rotary encoder or desolder them
• solder the KY-40s + pin to 3.3v of the Wemos
• solder the KY-40s GND pin to GND of the Wemos
• solder the KY-40s SW pin to configured BUTTON_PIN of the Wemos (dont use D8!) (default D5)
• solder the KY-40s CLK pin to configured ROTARY_PIN2 of the Wemos (default D7)
• solder the KY-40s DT pin to configured ROTARY_PIN1 of the Wemos (default D6)
• insert the KY-40 into the lid of the case (maybe you have to widen the hole a little bit for that)
• try to shorten the outstanding KY-40s pins on the bottom (be careful that you dont break something)
• fill the gapps between the KY40 and the lid with hotglue as good as possible and cover the whole back of the KY-40 with a 3-4mm thick layer of it. Be careful to clean all hot glue that will block the lids closing mechanism
• put the wemos in the case and close the lid with the KY-40 by pressing it together with the case
• put some hotglue into the rotary knob and press it on the rotary encoder

using the hardware on windows

• install rtpMIDI on your target machine
• initially connect your minivolumidi via usb to your pc, open a serial terminal and press the small reset button on the left side with a needle. You should now get a serial print out of the IP address, the name and the port of your minivolumidi.
• open rtpMIDI, add a session on the left side and enable it on the right side.
• add the minivolumidi in the Directory section with the data you gathered from the serial terminal
• press connect and test if it shows the connected client with a latency on the right side
• if everything works, you can now power the wemos everywhere in the wifi range of the configured network, without the usb connection and connect it via rtpMIDI
• open your DAW of choise and enable the rtpMIDI input and output channels
• map the midi parameter to whatever you want to control with it. Because of the wifi latency its not really useful for instant controls, but its perfect as a simple volume controller.

contributions

if you want to contribute to the project or if you have problems, dont hesitate to open issues or submit pull requests.