/*
This makes GIMPoletti a USB mouse, controlled with the IMUs gyroscope
LED colors correspond to the movement axis

TODO:
Interrupt driven IMU reading
Better scrolling
Gyro calibration triggered by button
Fancier LEDs
*/

#include “Mouse.h” //Library for USB CDC mouse profile, must also select “USB Support: HID” from Tools
#include <Wire.h> //i2c bus library, used to talk to IMU (MPU6050)
#include <Adafruit_NeoPixel.h> //Library for addressable LEDs (WS2812b)

// ====== Pin definitions ======
const uint8_t pwmPin = PA0; //Drives the speaker, PWM frequency on this generates sound at that frequency. DO NOT LEAVE HIGH!
const uint8_t pwmChannel = 1; //Channel of PWM timer connected to above pin
const uint8_t buttonPin = PB8; //Connected to the button. Low when pressed, high otherwise
const uint8_t ledPin = PA1; //Connected to the beginning of addressable LED string
const uint8_t sdaPin = PF0; //Hardware sda pin for i2c bus connected to IMU
const uint8_t sclPin = PF1; //Hardware scl pin for i2c bus connected to IMU

// ====== IMU variables ======
const uint8_t mpu_address = 0x68; //i2c address of the MPU6050 IMU chip
int16_t gx, gy, gz; //Gyro data values

const int16_t gx_offset = 0; //Offset values saved on IMU chip, it adds these to it’s raw output
const int16_t gy_offset = 0; //Adjust these if mouse drifts!
const int16_t gz_offset = 30;

// ====== Misc variables ======
const uint8_t ledCount = 6; //Number of LEDs on the string. There are 6 on GIMPoletti.

// ====== Mouse behaviour variables ======
int responseDelay = 5; //Loop delay
bool lastClickState; //Last status of click, used to detect change
uint32_t clickStamp = 0; //Timestamp of last detected click
uint32_t clickInhibitTime = 180; //Inhibit mousee movement for this many ms after a click, to minimize mouse jerking on click
uint32_t scrollInhibitThreshold = 50; //Inhibit scrolling if mouse movement is greater than this to prevent accidental scrolling
const uint8_t outConst = 120; //Maximum output value sent for mouse movement

// ====== Classes ======
Adafruit_NeoPixel strip(ledCount, ledPin, NEO_GRB + NEO_KHZ800); //Addressable LED library
//HardwareTimer *MyTim = new HardwareTimer(TIM2); //Timer for generating speaker PWM

void setup() {
pinMode(buttonPin, INPUT);
pinMode(pwmPin, OUTPUT);
Mouse.begin();

Wire.setSDA(sdaPin); //Set the i2c pins to the ones used in GIMPoletti circuit
Wire.setSCL(sclPin);
Wire.begin(); //Start the i2c bus

strip.begin(); // Initialize NeoPixel strip object
strip.show(); // Turn off all pixels ASAP
strip.setBrightness(40); // Set brightness, maximum is 255

// MyTim->setMode(pwmChannel, TIMER_OUTPUT_COMPARE_PWM1, pwmPin);
// MyTim->setOverflow(4000, HERTZ_FORMAT);
// MyTim->setCaptureCompare(pwmChannel, 50, PERCENT_COMPARE_FORMAT); // 50%

delay(10); //Wait a bit before talking to IMU just in case

Wire.beginTransmission(mpu_address); //Begin i2c transaction to device at this address
Wire.write(0x6B); //Set which register to write to, this is power management to turn on IMU
Wire.write(0x00); //Write 0x00 there to turn MPU6050 on
Wire.endTransmission(); //End transaction

//Unpack gyro biases into an array of uint_8 for sending over i2c
uint8_t toGyro[] = {gx_offset >> 8, gx_offset, gy_offset >> 8, gy_offset, gz_offset >> 8, gz_offset};

delay(10); //Wait a bit before talking to IMU just in case
Wire.beginTransmission(mpu_address); //Gyro offset registers, starting from X
Wire.write(0x13); //Set which register to write to, this is start of gyro bias bytes
Wire.write(&toGyro[0],6); //Write all values (each of the 3 has a 16 bit width consisting of 8 bit high and low part, so 6 in total)
Wire.endTransmission(); //End transaction

}

void loop() {

bool clickState = digitalRead(buttonPin);
if (clickState) {
//MyTim->resume();
//MyTim->setOverflow(3000, HERTZ_FORMAT);
}
else {
//MyTim->pause();
//digitalWrite(pwmPin,LOW);
}

if (clickState != lastClickState) {
clickStamp = millis();
lastClickState = clickState;
}

ReadGyro();

// calculate the movement distance based on the button states:
int xDistance = -gz / 256;
int yDistance = gy / 256;
int wheel = -gx;

//Do not scroll if vigorously moving mouse
if (abs(xDistance) > scrollInhibitThreshold || abs(yDistance) > scrollInhibitThreshold) {
wheel = 0;
}

if (millis() – clickStamp < clickInhibitTime) {
xDistance = 0;
yDistance = 0;
}

if (wheel > 0) {
wheel = max(0, wheel – 16000);
}
else {
wheel = min(0, wheel + 16000);
}
wheel /= 8192;

xDistance = constrain(xDistance, -outConst, outConst);
yDistance = constrain(yDistance, -outConst, outConst);
wheel = constrain(wheel, -outConst, outConst);

// if X or Y is non-zero, move:
if ((xDistance != 0) || (yDistance != 0)) {
Mouse.move(xDistance, yDistance, wheel);
}

// if the mouse button is pressed:
if (clickState == HIGH) {
// if the mouse is not pressed, press it:
if (!Mouse.isPressed(MOUSE_LEFT)) {
Mouse.press(MOUSE_LEFT);
}
}
// else the mouse button is not pressed:
else {
// if the mouse is pressed, release it:
if (Mouse.isPressed(MOUSE_LEFT)) {
Mouse.release(MOUSE_LEFT);

}
}
strip.fill(strip.Color(abs(xDistance) * 2, abs(yDistance) * 2, abs(gx) / 150), 0, 6);
strip.show();
// a delay so the mouse doesn’t move too fast:
delay(responseDelay);
}

void ReadGyro() {
Wire.beginTransmission(mpu_address);
Wire.write(0x43);
Wire.endTransmission();
Wire.requestFrom(0x68, 6);
gx = Wire.read() << 8 | Wire.read();
gy = Wire.read() << 8 | Wire.read();
gz = Wire.read() << 8 | Wire.read();
}