Introduction: Launchpad / Sequencer With MIDI Output

Picture of Launchpad / Sequencer With MIDI Output

For a project we had to make an instrument, we came up with the idea to make a Sequencer capable of sending MIDI data to a MIDI player. We made this using Arduino and Processing. It took us about 5 days to design the instrument, collect all of the parts, construct it, make the software and put it all together. The costs for making it where quite low, about €30 (about $40).

Step 1: Materials and Tools

Picture of Materials and Tools

Materials needed:

  • 64 3mm red LED's
  • 68 high pushbuttons
  • 64 220 Ohm resistors
  • 12 1K Ohm resistors
  • 4 10K Ohm linear potentiometers
  • 1 Arduino UNO
  • 1 USB cable
  • 1 16bit parallel I/O expander (MCP23016)
  • 1 3K Ohm resistor
  • 1 33pF capacitor
  • Perfboard (aproximately 70x70 holes)
  • Wires
  • 600x300mm triplex for lasercutter
  • 64 Doorstoppers
  • 1 latex glove

Tools needed:

  • Soldering iron
  • Wirestripper
  • Wirecutter
  • Sandpaper
  • Sharp knife
  • Woodglue
  • Lasercutter
  • Duct tape
  • Glue

Software needed:

  • Processing -
  • Arduino IDE -
  • optional a vecor file editor (illustrator, coreldraw)

To get the sequencer up and running you need some basic processing and arduino knowledge. Understanding how it works requires average knowledge of processing and arduino. But don't hesitate to take a look at the code and learn from it.

Step 2: Electronics

Picture of Electronics

We used multiplexing to control the LED's and at the same time we read the state of the buttons.We used a separate piece of perfboard for the I/O expander to make it fit inside the box. To make sure that the multiplexing worked fine we changed the I2C speed to 4kHz, take a look over here on how to do that.

Step 3: Box

Picture of Box

We used to make the box and edited it in Adobe Illustrator for the buttons. We made a pdf file of our design and cut the wood with the lasercutter.

Step 4: Code

The code is made and tested on a mac, windows does not have an internal MIDI input. It is possible to adapt the code to run on a Windows machine. We used the SoundCipher library to produce the MIDI.

Step 5: Buttons

Picture of Buttons

We used a sharp knife to cut the ridges from the side of the door stoppers and made them smooth using sanding paper. For keeping the buttons in place we put a latex glove on the back with duct tape and glued the buttons on top of it.

Step 6: Putting It Together

Picture of Putting It Together

Sandwich the electronics between the stand and the buttons, attach all of the wires to your arduino and connect it to your computer. Upload the firmware to the arduino and run the processing software. Then start a music program capable of playing MIDI, you should now be able to use the sequencer.


ParnabS (author)2015-12-15

Hey dude,how can i add RGB led and use it like real launchpad basically the led designs

MattS418 (author)ParnabS2017-09-03

yeah if you know pls tell me

balsuryana (author)2016-10-13

Good projects! but, i can find theMCP23016. Can i use another?

balsuryana (author)balsuryana2016-10-13

can i use MCP23017 ? Thanks.

MattS418 (author)2017-08-25

i am making project with neopixels but can you show me where you bought doorstops or a list where you bought and also you should male a youtube video you would get ALOT OF VIEWS

Matax (author)2017-07-04

What to do so it will work on Windows? Made everything now the program is just not working yet.

RenéM44 (author)2017-06-30

Is this working, did somebody try it?

d359nan (author)2017-06-12

any chance you could still show how you soldered the wires from under the board? Preferably diagrammatically. Thanks

Israeld7 (author)2017-01-06

Youtube or it didn´t happen XDD. Just kidding, but it would be great to see a youtube of this project working.

emieliot1 (author)2016-09-08

What is the program to run this, so the program to actually connect this to the computer.

MRecord (author)emieliot12016-09-09

We tested it on Ableton and FL studio, but any program that can handle MIDI over USB should work.

기성문 (author)2016-08-06

can you show me source code, i want make it work?

Doctorn (author)2016-04-09

What price did all the components cost? (roughly if you do not know the exact cost)

jfrankhauser (author)2016-03-10

do you have a better circuit diagram? if not I'll have to figure it out and make one myself. not complaining, just curious.

MRecord (author)jfrankhauser2016-03-11

No, I'm sorry. I made this project a long time ago, and at the time I did not make a better diagram.

jfrankhauser (author)MRecord2016-03-11

that's okay, in going to make a circuit diagram and PCB template for this. I'm also going to do a step by step. I'm going to post it on mine and reference you.

Does this schematic look correct?

Sergio Ulloa (author)2015-12-11

This is a realy cool project, but, can i build it with neopixels?

MRecord (author)Sergio Ulloa2015-12-13

Yes you could. At the time I did not have any neopixels, but I think it might be a great improvement. Means that you could probably get rid of the parallel I/O expander also. Please let me know if you manage to make one using neopixels.

MineAngerBR (author)MRecord2016-03-09

Have you tested this build with neopixels? I will be beginning to buy the parts for one project...

MRecord (author)MineAngerBR2016-03-11

No, I have not. It should be possible, but you have to figure that out. If you do, please make an instructable about it.

sarvamala (author)2015-08-12

hello, I'm sorry but I can not find the code you used ..
where is it?

ParnabS (author)2015-05-01

hey bro,can you add a more better schmatic and size of the box to make it in boxmaker and instruction of those 4 codes. hanks for this project and i hope you continue making stuff like this.

Catsruler1 (author)2015-03-31

Is there a schematic for the leds and buttons? I am trying to figure it out with the diagram and pictures but I am not 100% certain how it should be wired up. Help??

engineerknow (author)2015-03-07

where ? download inttypes.h
I use is error
help me please .

hgarg2 (author)2014-06-12

can i see any video of its working?

zombiemom42 (author)2014-02-05

Could you hook this up to ableton live?

MRecord (author)zombiemom422014-02-05

Yes, Ableton live supports MIDI input so you can hook it up to that. We have done some tests with FL studio, and it works really well.

selp (author)2014-02-05

Awsome ! I was planning to do that !

Door stoppers are not a bad idea !

After searching silicone pads for months, I was planning to use translucent silicone sheets (about 5mm thick) glued on another sheet (1mm)

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