Introduction: USB MIDI Controller
I started this project because of my love with music. I can play various instruments but I am just getting started with music production. Something that I thought was useful was a MIDI controller which I would use to play samples with and have a bunch of potmeters used for volume control and various other effects. I also wanted to be able to turn of the potmeters any time I wanted. In this instructable I will show the steps to make the MIDI controller and my own experience creating it. As of now it is not finished.
In the pictures above you can find some drawings and a "flow chart" I made prior to starting the project. And the end product
Step 1: Parts and Tools
Here is a list of parts and tools needed for the project with some optionals:
1. Arduino Leonardo, or Micro
2. Adafruit Trellis with membrane
3. 3 10k Ohm linear potmeters
4. 3 10k Ohm linear mono slide potmeters (You can use stereo pots but I wouldn't recommend them)
5. Some screws (nuts are not needed)
6. Enough cables
1. Laser cutter
2. 3D printer
3. Soldering iron and solder
1. Adobe Illustrator
2. A Tinkercad account
Step 2: The Case
The wooden box is made using Adobe Illustrator and a laser cutter. Its an 180mm x 60mm x 100mm size box made with makercase.com the material is 3mm thick and and it has finger edges. On top of the box are holes for the pots and the trellis to fit in. The bottom of the box has flat edges this is important for later.
After you have all the pieces for the box check if the pots and the trellis fit. If not use a file to make the holes bigger. The holes for the slide pots came out extremely small I had to make them bigger using a small sort of buzz saw. Don't worry if the holes are a bit too large, as long as the're not bigger than the nut of the pot you should be alright.
Now glue the box together using wood glue every part except for the bottom.
The arduino will be attached to the bottom you can do this in two ways. If you want to use the arduino for a different project later drill holes in the bottom of the box and attach the arduino with screws. Else you can glue the arduino to the bottom like I did. Positioning is key. Most of the wires will come from the pots so having the arduino under the pots is the best position. To make sure the cable can come out of the box put the cable in the arduino and draw with a pencil the line the cable will follow out of the box. On the side the cable will come out file a hole the size of the cable. The bottom is detachable so if you need to use the cable for something else you can take it out whenever you like.
Its important for the bottom to not fall into the box so take two small bits of wood and place them 3mm into the box preferably next to the hole you created for the cable. The force from the wood will keep the bottom in place if you're worried the bottom will fall out though you can use a bit of tape.
Step 3: 3D Printing
A couple of parts need to be 3D printed these include :
Two hinges, a fitting for the trellis and four support pieces. The fitting for the trellis is 70mm x 84mm so make sure you have enough room to print it out.
Step 4: Assembly
The first thing to place in the box will be the trellis. The're aren't any holes on top of the box so you'll need to drill them yourself. Place the fitting of the trellis that you've 3d printed and with a pencil draw through the holes on the fitting. Grab a drill and carefully drill through the wood.
Solder 4 wires on the trellis. On SCL, SDA 5v and GND.
Place the membrane, the trellis and the fitting inside the box. Put screws through the holes you've made and through the holes of the fitting. If the screw is too large for the fitting force them through or make the holes of the fitting larger by drilling through them.
Next in the middle of the holes for the slide pots drill two small holes. Put the slide pots in their place and take a small but thick piece of wood long enough to overlap the slide pots. Place the piece of wood over the slide pots and drill two screws in the wood.
And finally grab the three turn pots and solder two wires. One on the left and one on the right. This will make soldering later much easier.
Glue the support pieces on the bottom of the box on each side one
Step 5: Soldering
This is the most frustrating part and I will not go into much detail on how to solder everything together but there are some things that are important to know.
Both type of pots have three things to solder: the voltage, ground and output. On the slide pots the 2 ground and 1 output are on one side of the pot, 3 voltage on the other.
Solder every ground together and every voltage together. The output will go into the analog ports of the arduino. The cable you have left from soldering every ground must go to the middle part of the toggle switch. The other cable from the toggle switch goes into one of the GND ports of the arduino. The final cable you get from soldering all the voltages together must be soldered together with the 5v cable from the trellis. The cable you have left goes into the 5v port of the arduino. The two cables that are left from the trellis need to go into the SCL and SDA ports.
In the end a problem I encountered was that the switch I wanted to use to turn off the pots did the exact opposite. I thought that it would put everything to 0 because the power going to them was cut off by the switch. Instead it put everything to its max. Which can also give a cool effect. ;)
Step 6: Code
As of now I don't have a code that works with software like Pro Tools or Ableton. However the controller does get recognized by Ableton as a midi device. For now its best to check if all the individual components work. For this I used a test code from the arduino website and one from the adafruit website