Core Electronics Forum

TEE1010 Part 3 - Modifying the Insides - A FCB1010 rebuild with a Teensy 4.1

I’m am rebuilding a FCB1010 into something that is more capable. To do this I am gutting the internals and installing a Teensy 4.1 and Teensy Audio card. I have delusions of it working like a bass pedal, MIDI sequencer and/or drum machine.

In this Video I explain how I modified the inside electronics. You can tell by the soldering and general construction that I am more of a programmer!


Hi John,

That’s excellent! Pretty impressive what the Teensy with an appropriate Audio card is able to do. I’d imagine you’ve seen The Euclidean a project Ken was working on a while back, might be an idea for another project to put together:

Also, I’m working on a little PR for your code at the moment. Just want to grab a Teensy from stock and ensure that my modifications will work correctly before I create a commit for it :wink:


Thanks. The code is just for testing, but feel free to make suggestions.
I have seen the project you suggested. I am interested but I have a lot of ideas to go through on the current project…


Hey John,

No worries. Thought I’d make a suggestion to see whether it’s something you can use in the final project to make it shorter. I mainly modified your function readSwitches() to use a for loop iterating over an array rather than checking every single value in an if-statement.

/* Testing Hardware for TEE1010
   By John Melki-Wegner (aka Expensive Notes)

// === MIDI ==================================================================== MIDI
#include <MIDI.h>
MIDI_CREATE_INSTANCE(HardwareSerial, Serial7, MIDI);
int channel = 1;

// === Variables =============================================================== Variables

int reading;           // the current reading from the input pin
//Pots :  Analogue pins
const int potPin[] = {A0, A8, A14, A15, A16, A17};   // Input pins from the potentiometers
int potVals[6]; //input values from pots

const int foot[] = {0, 1, 2, 3, 4, 5, 30, 31, 32, 33, 36, 37, 26, 27, 34}; // Note that the last five positions represent footUp, footDown and the three additional switches respectively
const int additionalSwitch[] = {26, 27, 34};

const char footPrint[][12] = {" foot1 ", " foot2 ", " foot3 ", " foot4 ", " foot5 ", " foot6 ", " foot7 ", " foot8 ", " foot9 ", " foot10 ", " footUp ", " footDown ", " addSwitch1 ", " addSwitch2 ", " addSwitch3 "};

// #define numberSwitches 15 // This appears to be unused, just commenting up

//=== Oled Screen ================================================================ Oled Screen
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define OLED_RESET     4 // Reset pin # 
#define SCREEN_ADDRESS 0x3C // Found using scanner

//Changed Wire to Wire2 for SCL2 and SDA2 Yay!
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire2, OLED_RESET);

// === MIDI ========================================================================= MIDI
byte stopMIDI = 0xfc; //MIDI stop
byte midi_clock = 0xf8;
int note = 60;
int BPM = 250;//Beats per Minute maximum?
int waitTime = 40; //Time between sending MIDI clock
int spareTime = 40; //Time left after processes are done that needs to be padded/wasted while waiting for mext beat/note

// === Setup ======================================================================== Setup

void setup()
  //USB Serial for debugging

  for (int cFoot : foot) pinMode(cFoot, INPUT_PULLUP); // Sets every pin in foot to

  //MIDI Serial in and out
  Serial7.begin(31250); //MIDI baud rate
  Serial7.write(stopMIDI); // just in case

  MIDI.begin(MIDI_CHANNEL_OMNI);                      // Launch MIDI and listen to channel 1

  //--- Screen ------------------------------------------------
  //   SSD1306_SWITCHCAPVCC = generate display voltage from 3.3V internally
  if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
    for (;;); // Don't proceed, loop forever

// === Loop ======================================================================== Loop

void loop()
  int t1 = millis();

  int t2 = millis();
  Serial.print("\tTime to Read Switches etc. :\t");
  Serial.print(t2 - t1);
  Serial.print("\tSpare time:\t");
  spareTime = waitTime - (t2 - t1);
  Serial.print("\tMIDI in?? ");
  while (t2 - t1 < waitTime) {
    if ( {
      byte type = MIDI.getType();
    t2 = millis();

// === ============================================================================

void showScreen() {
  display.setTextColor(SSD1306_WHITE); // Draw white text
  display.setCursor(15, 0);
  display.setCursor(15, 20);

void sendMIDInote() {
  MIDI.sendNoteOff(note, 100, channel);
  if (note > 65) note = 60;
  MIDI.sendNoteOn(note, 100, channel);

void readPots() {
  for (int i = 0; i < 6; i++) {
    potVals[i] = analogRead(potPin[i]);
    Serial.print("  ");
  BPM = map( potVals[0] , 0, 1023, 20, 250);
  waitTime = int(60000 / BPM / 6); //Time between MIDI clock out

void readSwitches() {
  for (int iter = 0; iter < 16; iter++) if (digitalRead(foot[iter]) == LOW) Serial.print(footPrint[iter]);

Thanks Bryce. I usually do what you have suggested and iterate through arrays. For example, in the real program I will have arrays inside arrays in order to implement key and scale changes. I was just being lazy with this program. Your use of the constant char array was great idea for the names of the pedals. I appreciate your feedback, thanks for taking the time to improve it.

One thing I have very little experience with it GitHub so I am not sure if I have accepted your changes correctly.


Hi John,

It looks like the pull request was closed without being committed to the main branch where your code currently is, all is not lost though, this topic on StackOverflow goes through how to merge a closed branch! github - Git : How to merge the changes from a closed pull request? - Stack Overflow

Git can be a bit awkward to get started with but their documenation does a good job at keeping things succinct and detailed: Merging a pull request - GitHub Docs


1 Like

Thanks for your help Liam. I ended up just adding the new version to Github, unfortunately that means Bryce’s work isn’t acknowledged. However, it is appreciated. Next time I will try to use Github properly.

1 Like

Hey John,

No worries at all!
A quick Google search should get them pointed at this forum topic, though a comment might be a good way to link everything together.

I’m loving the updates by the way, the video explanations are superbly sucinct and give a lot of info!


Thanks. Appreciate the nice comment.