I have a very specific project -
I want to illuminate an LED strip (5v but powered separately) for 7-10 seconds when an a ground mounted upright (a 42 mm pole) receives a contact from a moving object (a ball). My plan is to test if an MPU 6050 interfaced with an Arduino Uno (ultimately an embedded Micro Pro) is capable of detecting contacts across a wide range of conditions from direct hits to very light contacts.
To-date I have managed to upload and run an I2C program that provides a range of variables potentially capable of responding to contacts (the best variables are yet to be determined), -
#include <Wire.h>
long accelX, accelY, accelZ;
float gForceX, gForceY, gForceZ;
long gyroX, gyroY, gyroZ;
float rotX, rotY, rotZ;
void setup() {
Serial.begin(9600);
Wire.begin();
setupMPU();
}
void loop() {
recordAccelRegisters();
recordGyroRegisters();
printData();
delay(100);
}
void setupMPU(){
Wire.beginTransmission(0b1101000); //This is the I2C address of the MPU (b1101000/b1101001 for AC0 low/high datasheet sec. 9.2)
Wire.write(0x6B); //Accessing the register 6B - Power Management (Sec. 4.28)
Wire.write(0b00000000); //Setting SLEEP register to 0. (Required; see Note on p. 9)
Wire.endTransmission();
Wire.beginTransmission(0b1101000); //I2C address of the MPU
Wire.write(0x1B); //Accessing the register 1B - Gyroscope Configuration (Sec. 4.4)
Wire.write(0x00000000); //Setting the gyro to full scale +/- 250deg./s
Wire.endTransmission();
Wire.beginTransmission(0b1101000); //I2C address of the MPU
Wire.write(0x1C); //Accessing the register 1C - Acccelerometer Configuration (Sec. 4.5)
Wire.write(0b00000000); //Setting the accel to +/- 2g
Wire.endTransmission();
}
void recordAccelRegisters() {
Wire.beginTransmission(0b1101000); //I2C address of the MPU
Wire.write(0x3B); //Starting register for Accel Readings
Wire.endTransmission();
Wire.requestFrom(0b1101000,6); //Request Accel Registers (3B - 40)
while(Wire.available() < 6);
accelX = Wire.read()<<8|Wire.read(); //Store first two bytes into accelX
accelY = Wire.read()<<8|Wire.read(); //Store middle two bytes into accelY
accelZ = Wire.read()<<8|Wire.read(); //Store last two bytes into accelZ
processAccelData();
}
void processAccelData(){
gForceX = accelX / 16384.0;
gForceY = accelY / 16384.0;
gForceZ = accelZ / 16384.0;
}
void recordGyroRegisters() {
Wire.beginTransmission(0b1101000); //I2C address of the MPU
Wire.write(0x43); //Starting register for Gyro Readings
Wire.endTransmission();
Wire.requestFrom(0b1101000,6); //Request Gyro Registers (43 - 48)
while(Wire.available() < 6);
gyroX = Wire.read()<<8|Wire.read(); //Store first two bytes into accelX
gyroY = Wire.read()<<8|Wire.read(); //Store middle two bytes into accelY
gyroZ = Wire.read()<<8|Wire.read(); //Store last two bytes into accelZ
processGyroData();
}
void processGyroData() {
rotX = gyroX / 131.0;
rotY = gyroY / 131.0;
rotZ = gyroZ / 131.0;
}
void printData() {
Serial.print("Gyro (deg)");
Serial.print(" X=");
Serial.print(rotX);
Serial.print(" Y=");
Serial.print(rotY);
Serial.print(" Z=");
Serial.print(rotZ);
Serial.print(" Accel (g)");
Serial.print(" X=");
Serial.print(gForceX);
Serial.print(" Y=");
Serial.print(gForceY);
Serial.print(" Z=");
Serial.println(gForceZ);
}
I have also managed to find a relay program (and breadboard circuit with 5v relay, diode, 2n222 transistor and 1K resistor) which works well with the following code -
// connect digital pin 8 to the transistor, via a resistor
int led = 8;
// the setup routine runs once when you press reset:
void setup() {
// initialize the digital pin as an output.
pinMode(led, OUTPUT);
}
// the loop routine runs over and over again forever:
void loop() {
delay(5000); // wait for 5 seconds
digitalWrite(led, HIGH); // turn the relay off
delay(5000); // wait for a second
digitalWrite(led, LOW); // turn the relay on
}
My main question is - how can I link these sketches so that a specific output from the 6050 might trigger a change in the relay state.
I don't need the Serial.print output.
I want the main MPU program to return to the state where it reads the 6050 output ready for the next impact contact.
As an inexperienced Arduino user (I bought a Uno 5 days ago) I suspect that I need to become familiar with Interrupts (ISRs). If this is the case I would very much welcome some help and guidance.
GB