Introduction: Arduino Based ZOOM MS70-cdr Midi Program Changer

This project is based on Lawrence Doss 's one. The only difference is on the choice of the usb host device (in this case a USBHOST2 from Hobby Tronic with Midi firmware on. If you haven't or cannot afford this device, please see my other instructable to try other shield. Here is an exemple of what you can generally make with an Arduino bord, here a Uno one and 2 switches. The number of presets depending of how many switches you need and the capacity of the Arduino board obviously.

Step 1: MS70 Arduino Midi Program Change


1. arduino UNO - chinese one they're cheaper

2. USBHost from Hobby Tronic

3. two momentary spst footswitches (or more than two depending on which example you'll take)

4. spare electrical cable

5. a box to fit all

6. a usb cable between usb shield and Zoom pedal + another one to program the arduino (different type)

7. spare arduino's male pins

8. nine to twelve volts transformator (positive center pin) for the Arduino

9. ZOOM MS70-cdr obviously / with its own power supply (negative center 9V.)


1. soldering device

2. iron

3. drilling tools if you want to fix all in the box

4. some hot glue always help!

5. Arduino simulator free @ (optional)


Step 2:

Solder cables with the male pins and the instant switches (see schematic), the choice of the pins is yours just adapt the code and send it thru your Arduino ide (mine is version 1.8.5). Pay attention that these chinese Arduinos need a proper driver.

Connect the usb host to your Zoom pedal, it doesn't need proper power when connected to USB but it's less noisy .

Plug your Arduino board to power transformer (wait a moment)

Test all the thing, it must do work! If not, check out all cables and wiring.


Step 3:

if it works disconnect it all, fix it all in your case (some drill work needed here)

drill a hole for power plug and another for the usb host, ensuring that it all fits in your box before.

Don't forget to drill holes for your switches, except if you plan to make'em externals...

I suggest to put a little hot glue on the soldered males pin and to NOT solder anything directly on your Arduino board.


Step 4:

Upload the exemple code here below but pay attention that they are two different schematics as two different projects like exemples... Connect it all again and enjoy!

You normally do have in the exemple 1 below, one switch to increase preset and another to decrease . For any other kind of controls just adapt your ino sketch. If you need help just ask.


Arduino example code (see below):

added: the sketch named MS70_4patches_2banks is an example suggested by a follower that involved 4 switches (4 patches) and 1 switch to select bank A or B, by ex: 1 to 4 = A / 5 to 8 = B.

Just adapt code to hardware (pin numbers etc...)


Step 2: Personal Links of Interest

check out the most outstanding band I actually play on !


Microcontroller Contest 2017

Participated in the
Microcontroller Contest 2017