// NEW IN VERSION 1.5: // Changed pin 8 from standard servo to normal digital output // NEW IN VERSION 1.4: // Changed Serial.print() for Serial.write() in ScratchBoardSensorReport function to make it compatible with latest Arduino IDE (1.0) // NEW IN VERSION 1.3: // Now it works on GNU/Linux. Also tested with MacOS and Windows 7. // timer2 set to 20ms, fixing a glitch that made this period unstable in previous versions. // readSerialport() function optimized. // pulse() modified so that it receives pulse width as a parameter instead using a global variable. // updateServoMotors changes its name as a global variable had the same name. // Some minor fixes. // Thanks to Jorge Gomez for all these new fixes! #define TIMER2_PRELOAD 100 char outputs[10]; int states[10]; unsigned long initialPulseTime; unsigned long lastDataReceivedTime; volatile boolean updateServoMotors; volatile boolean newInterruption; void setup() { Serial.begin(38400); Serial.flush(); configurePins(); configureServomotors(); initServos(); lastDataReceivedTime = millis(); } void loop() { if (updateServoMotors) { sendUpdateServomotors(); sendSensorValues(); updateServoMotors = false; } else { readSerialPort(); } } void initServos(){ //======================== //Modify the angle for each servos //======================== states[1] = 25; // claw states[5] = 125; // left (up/down) states[6] = 70; // right (forward/backward) states[7] = 90; // base //======================== servomotorS(5, states[1]); servomotorS(9, states[5]); servomotorS(10, states[6]); servomotorS(11, states[7]); } void configurePins() { for (int index = 0; index < 10; index++) { states[index] = 0; pinMode(index+4, OUTPUT); //digitalWrite(index+4, LOW); //reset pins } pinMode(2,INPUT); pinMode(3,OUTPUT); outputs[0] = 'c'; //pin 4 outputs[1] = 's'; //pin 5 outputs[2] = 'a'; //pin 6 outputs[3] = 'c'; //pin 7 outputs[4] = 's'; //pin 8 outputs[5] = 's'; //pin 9 outputs[6] = 's'; //pin 10 outputs[7] = 's'; //pin 11 outputs[8] = 'd'; //pin 12 outputs[9] = 'd'; //pin 13 } void configureServomotors() //servomotors interruption configuration (interruption each 10 ms on timer2) { newInterruption = false; updateServoMotors = false; TCCR2A = 0; TCCR2B = 1< 0) && ( array[j] < array[j-1] ); j--) swap( array, j, j-1 ); } void swap (int* array, int a, int b) { int temp = array[a]; array[a] = array[b]; array[b] = temp; } void ScratchBoardSensorReport(int sensor, int value) //PicoBoard protocol, 2 bytes per sensor { Serial.write( B10000000 | ((sensor & B1111)<<3) | ((value>>7) & B111)); Serial.write( value & B1111111); } void readSerialPort() { int pin, inByte, sensorHighByte; if (Serial.available() > 1) { lastDataReceivedTime = millis(); inByte = Serial.read(); if (inByte >= 128) // Are we receiving the word's header? { sensorHighByte = inByte; pin = ((inByte >> 3) & 0x0F); while (!Serial.available()); // Wait for the end of the word with data inByte = Serial.read(); if (inByte <= 127) // This prevents Linux ttyACM driver to fail { if (pin == 3) pin = 12; //using pin12 as map to pin3 states[pin - 4] = ((sensorHighByte & 0x07) << 7) | (inByte & 0x7F); updateActuator(pin - 4); } } } else checkScratchDisconnection(); } void reset() //with xbee module, we need to simulate the setup execution that occurs when a usb connection is opened or closed without this module { for (int pos = 0; pos < 10; pos++) //stop all actuators { if (pos != 1 && pos != 5 && pos != 6 && pos != 7){ states[pos] = 0; digitalWrite(pos + 4, LOW); } } //reset servomotors newInterruption = false; updateServoMotors = false; TCNT2 = TIMER2_PRELOAD; //protocol handshaking sendSensorValues(); lastDataReceivedTime = millis(); } void updateActuator(int pinNumber) { if (pinNumber == 8) digitalWrite(3, states[8]); else if (outputs[pinNumber] == 'd') digitalWrite(pinNumber + 4, states[pinNumber]); else if (outputs[pinNumber] == 'a') analogWrite(pinNumber + 4, states[pinNumber]); } void sendUpdateServomotors() { for (int p = 0; p < 10; p++) { if (outputs[p] == 'c') servomotorC(p + 4, states[p]); if (outputs[p] == 's') servomotorS(p + 4, states[p]); } } void servomotorC (int pinNumber, int dir) { if (dir == 1) pulse(pinNumber, 1300); //clockwise rotation else if (dir == 2) pulse(pinNumber, 1700); //anticlockwise rotation } void servomotorS (int pinNumber, int angle) { if (angle > 0 and angle < 180) { if (angle < 0) pulse(pinNumber, 600); else if (angle > 180) pulse(pinNumber, 2400); else pulse(pinNumber, (angle * 10) + 600); } } void pulse (int pinNumber, int pulseWidth) { initialPulseTime = micros(); digitalWrite(pinNumber, HIGH); while (micros() < pulseWidth + initialPulseTime){} digitalWrite(pinNumber, LOW); } void checkScratchDisconnection() //the reset is necessary when using an wireless arduino board (because we need to ensure that arduino isn't waiting the actuators state from Scratch) or when scratch isn't sending information (because is how serial port close is detected) { if (millis() - lastDataReceivedTime > 1000) reset(); //reset state if actuators reception timeout = one second } ISR(TIMER2_OVF_vect) //timer1 overflow interrupt vector handler { //timer2 => 8 bits counter => 256 clock ticks //preeescaler = 1024 => this routine is called 61 (16.000.000/256/1024) times per second approximately => interruption period = 1 / 16.000.000/256/1024 = 16,384 ms //as we need a 20 ms interruption period but timer2 doesn't have a suitable preescaler for this, we program the timer with a 10 ms interruption period and we consider an interruption every 2 times this routine is called. //to have a 10 ms interruption period, timer2 counter must overflow after 156 clock ticks => interruption period = 1 / 16.000.000/156/1024 = 9,984 ms => counter initial value (TCNT) = 100 if (newInterruption) { updateServoMotors = true; } newInterruption = !newInterruption; TCNT2 = TIMER2_PRELOAD; //reset timer }