Psi Swarm Robot
Library for the PsiSwarm Robot - Version 0.7
Fork of
PsiSwarmLibrary
by 
James Hilder
Diff: sensors.cpp
- Revision:
- 0:d6269d17c8cf
- Child:
- 1:060690a934a9
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/sensors.cpp Thu Feb 04 21:48:54 2016 +0000
@@ -0,0 +1,480 @@
+/* University of York Robotics Laboratory PsiSwarm Library: Sensor Functions Source File
+ *
+ * File: sensors.cpp
+ *
+ * (C) Dept. Electronics & Computer Science, University of York
+ * James Hilder, Alan Millard, Alexander Horsfield, Homero Elizondo, Jon Timmis
+ *
+ * PsiSwarm Library Version: 0.4
+ *
+ * February 2016
+ *
+ *
+ */
+
+#include "psiswarm.h"
+
+//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// Ultrasonic Sensor (SRF02) Functions
+//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+// The ultrasonic sensor needs a start command to be sent: this is done by calling update_ultrasonic_measure().
+// It can be set to automatically refresh at 10Hz by called enable_ultrasonic_ticker and disable with disabled_ultrasonic_ticker
+
+void enable_ultrasonic_ticker(){
+ ultrasonic_ticker.attach_us(update_ultrasonic_measure,100000);
+}
+
+void disable_ultrasonic_ticker(){
+ ultrasonic_ticker.detach();
+}
+
+void update_ultrasonic_measure(){
+ if(waiting_for_ultrasonic == 0){
+ waiting_for_ultrasonic = 1;
+
+ char command[2];
+ command[0] = 0x00; // Set the command register
+ command[1] = 0x51; // Get result is centimeters
+ primary_i2c.write(ULTRASONIC_ADDRESS, command, 2); // Send the command to start a ranging burst
+
+ ultrasonic_timeout.attach_us(IF_read_ultrasonic_measure,70000);
+ }else{
+ debug("WARNING: Ultrasonic sensor called too frequently.\n");
+ }
+}
+
+void IF_read_ultrasonic_measure(){
+ char command[1];
+ char result[2];
+ command[0] = 0x02; // The start address of measure result
+ primary_i2c.write(ULTRASONIC_ADDRESS, command, 1, 1); // Send address to read a measure
+ primary_i2c.read(ULTRASONIC_ADDRESS, result, 2); // Read two byte of measure
+ ultrasonic_distance = (result[0]<<8)+result[1];
+ ultrasonic_distance_updated = 1;
+ waiting_for_ultrasonic = 0;
+ debug("US:%d cm\n",ultrasonic_distance);
+}
+
+//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// Additional Sensing Functions
+//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+float get_temperature(){
+ return IF_read_from_temperature_sensor();
+}
+
+//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// Voltage Sensing Functions
+//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+float get_battery_voltage (){
+ float raw_value = vin_battery.read();
+ return raw_value * 4.95;
+}
+
+float get_current (){
+ // Device uses a INA211 current sense monitor measuring voltage drop across a 2mOhm resistor
+ // Device gain = 500
+ float raw_value = vin_current.read();
+ return raw_value * 3.3;
+}
+
+float get_dc_voltage (){
+ float raw_value = vin_dc.read();
+ return raw_value * 6.6;
+}
+
+//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+// IR Sensor Functions
+//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
+
+// Estimates the distance to an obstacle from one of the IR sensors, defined by index (range 0-7).
+// The value is converted to an approximate distance in millimetres, or 100.0 if no obstacle found.
+// NB This function is preserved for code-compatability and cases where only a single reading is needed
+// In many cases it is preferable to call store_reflected_ir_distances() to save all 8 values then read using get_reflected_ir_distance()
+float read_reflected_ir_distance ( char index ){
+ // Sanity check
+ if(index>7) return 0.0;
+
+ //1. Read the ADC value without IR emitter on; store in the background_ir_values[] array
+ background_ir_values [index] = IF_read_IR_adc_value(1, index );
+
+ //2. Enable the relevant IR emitter by turning on its pulse output
+ switch(index){
+ case 0: case 1: case 6: case 7:
+ IF_set_IR_emitter_output(0, 1);
+ break;
+ case 2: case 3: case 4: case 5:
+ IF_set_IR_emitter_output(1, 1);
+ break;
+ }
+ wait_us(ir_pulse_delay);
+
+ //3. Read the ADC value now IR emitter is on; store in the illuminated_ir_values[] array
+ illuminated_ir_values [index] = IF_read_IR_adc_value (1, index );
+
+ //4. Turn off IR emitter
+ switch(index){
+ case 0: case 1: case 6: case 7:
+ IF_set_IR_emitter_output(0, 0);
+ break;
+ case 2: case 3: case 4: case 5:
+ IF_set_IR_emitter_output(1, 0);
+ break;
+ }
+
+ //5. Estimate distance based on 2 values using calculate_reflected_distances(); store in reflected_ir_distances()
+ reflected_ir_distances [index] = calculate_reflected_distance( background_ir_values [index], illuminated_ir_values [index]);
+ ir_values_stored = 1;
+ return reflected_ir_distances [index];
+}
+
+
+// Returns the stored value of the reflected obstacle based on last call of either read_reflected_ir_distance or store_reflected_distances
+float get_reflected_ir_distance ( char index ){
+ // Sanity check: check range of index and that values have been stored
+ if (index>7 || ir_values_stored == 0) return 0.0;
+ return reflected_ir_distances[index];
+}
+
+// Returns the stored value of the non-illuminated sensor based on last call of store_background_raw_ir_values
+unsigned short get_background_raw_ir_value ( char index ){
+ // Sanity check: check range of index and that values have been stored
+ if (index>7 || ir_values_stored == 0) return 0.0;
+ return background_ir_values[index];
+}
+
+// Returns the stored value of the illuminated sensor based on last call of store_illuminated_raw_ir_values
+unsigned short get_illuminated_raw_ir_value ( char index ){
+ // Sanity check: check range of index and that values have been stored
+ if (index>7 || ir_values_stored == 0) return 0.0;
+ return illuminated_ir_values[index];
+}
+
+// Stores the reflected distances for all 8 IR sensors
+void store_reflected_ir_distances ( void ){
+ store_ir_values();
+ for(int i=0;i<8;i++){
+ reflected_ir_distances [i] = calculate_reflected_distance( background_ir_values [i], illuminated_ir_values [i]);
+ }
+}
+
+// Stores the rbackground and illuminated values for all 8 IR sensors
+void store_ir_values ( void ){
+ store_background_raw_ir_values();
+ store_illuminated_raw_ir_values();
+}
+
+// Stores the raw ADC values for all 8 IR sensors without enabling IR emitters
+void store_background_raw_ir_values ( void ){
+ ir_values_stored = 1;
+ for(int i=0;i<8;i++){
+ background_ir_values [i] = IF_read_IR_adc_value(1,i);
+ }
+}
+
+// Stores the raw ADC values for all 8 IR sensors with a 500us emitter pulse
+void store_illuminated_raw_ir_values ( void ){
+ //1. Enable the front IR emitters and store the values
+ IF_set_IR_emitter_output(0, 1);
+ wait_us(ir_pulse_delay);
+ illuminated_ir_values [0] = IF_read_IR_adc_value(1,0);
+ illuminated_ir_values [1] = IF_read_IR_adc_value(1,1);
+ illuminated_ir_values [6] = IF_read_IR_adc_value(1,6);
+ illuminated_ir_values [7] = IF_read_IR_adc_value(1,7);
+ IF_set_IR_emitter_output(0, 0);
+
+ //2. Enable the rear+side IR emitters and store the values
+ IF_set_IR_emitter_output(1, 1);
+ wait_us(ir_pulse_delay);
+ illuminated_ir_values [2] = IF_read_IR_adc_value(1,2);
+ illuminated_ir_values [3] = IF_read_IR_adc_value(1,3);
+ illuminated_ir_values [4] = IF_read_IR_adc_value(1,4);
+ illuminated_ir_values [5] = IF_read_IR_adc_value(1,5);
+ IF_set_IR_emitter_output(1, 0);
+}
+
+// Converts a background and illuminated value into a distance
+float calculate_reflected_distance ( unsigned short background_value, unsigned short illuminated_value ){
+ float approximate_distance = 4000 + background_value - illuminated_value;
+ if(approximate_distance < 0) approximate_distance = 0;
+
+ // Very approximate: root value, divide by 2, approx distance in mm
+ approximate_distance = sqrt (approximate_distance) / 2.0;
+
+ // Then add adjustment value if value >27
+ if(approximate_distance > 27) {
+ float shift = pow(approximate_distance - 27,3);
+ approximate_distance += shift;
+ }
+ if(approximate_distance > 90) approximate_distance = 100.0;
+ return approximate_distance;
+}
+
+// Returns the illuminated raw sensor value for the IR sensor defined by index (range 0-7); turns on the emitters for a 500us pulse
+unsigned short read_illuminated_raw_ir_value ( char index ){
+ //This function reads the IR strength when illuminated - used for PC system debugging purposes
+ //1. Enable the relevant IR emitter by turning on its pulse output
+ switch(index){
+ case 0: case 1: case 6: case 7:
+ IF_set_IR_emitter_output(0, 1);
+ break;
+ case 2: case 3: case 4: case 5:
+ IF_set_IR_emitter_output(1, 1);
+ break;
+ }
+ wait_us(ir_pulse_delay);
+ //2. Read the ADC value now IR emitter is on
+ unsigned short strong_value = IF_read_IR_adc_value( 1,index );
+ //3. Turn off IR emitter
+ switch(index){
+ case 0: case 1: case 6: case 7:
+ IF_set_IR_emitter_output(0, 0);
+ break;
+ case 2: case 3: case 4: case 5:
+ IF_set_IR_emitter_output(1, 0);
+ break;
+ }
+ return strong_value;
+}
+
+// Base IR sensor functions
+
+
+// Returns the stored value of the non-illuminated sensor based on last call of store_background_base_ir_values
+unsigned short get_background_base_ir_value ( char index ){
+ // Sanity check: check range of index and that values have been stored
+ if (index>4 || base_ir_values_stored == 0) return 0.0;
+ return background_base_ir_values[index];
+}
+
+// Returns the stored value of the illuminated sensor based on last call of store_illuminated_base_ir_values
+unsigned short get_illuminated_base_ir_value ( char index ){
+ // Sanity check: check range of index and that values have been stored
+ if (index>4 || base_ir_values_stored == 0) return 0.0;
+ return illuminated_base_ir_values[index];
+}
+
+// Stores the reflected distances for all 5 base IR sensors
+void store_base_ir_values ( void ){
+ store_background_base_ir_values();
+ store_illuminated_base_ir_values();
+ //for(int i=0;i<5;i++){
+ // reflected_ir_distances [i] = calculate_reflected_distance( background_base_ir_values [i], illuminated_base_ir_values [i]);
+ //}
+}
+
+// Stores the raw ADC values for all 5 base IR sensors without enabling IR emitters
+void store_background_base_ir_values ( void ){
+ base_ir_values_stored = 1;
+ for(int i=0;i<5;i++){
+ background_base_ir_values [i] = IF_read_IR_adc_value(2,i);
+ }
+}
+
+// Stores the raw ADC values for all 5 base IR sensors with a 500us emitter pulse
+void store_illuminated_base_ir_values ( void ){
+ //1. Enable the base IR emitters and store the values
+ IF_set_IR_emitter_output(2, 1);
+ wait_us(base_ir_pulse_delay);
+ for(int i=0;i<5;i++){
+ illuminated_base_ir_values [i] = IF_read_IR_adc_value(2,i);
+ }
+
+ IF_set_IR_emitter_output(2, 0);
+}
+
+// Routine to store detected line position in a similar format to the used on 3Pi\m3Pi\PiSwarm
+void store_line_position ( ){
+ // Store background and reflected base IR values
+ store_base_ir_values();
+ int h_value[5];
+ int line_threshold = 1000;
+ int line_threshold_hi = 2000;
+ char count = 0;
+ line_found = 0;
+ line_position = 0;
+ for(int i=0;i<5;i++){
+ if(get_background_base_ir_value(i) > get_illuminated_base_ir_value(i)) h_value[i]=0;
+ else h_value[i] = get_illuminated_base_ir_value(i) - get_background_base_ir_value(i);
+ if(h_value[i] < line_threshold) count++;
+ }
+ if(count == 1){
+ line_found = 1;
+ if(h_value[0] < line_threshold) {
+ line_position = -1;
+ if(h_value[1] < line_threshold_hi) line_position = -0.8;
+ }
+
+ if (h_value[1] < line_threshold) {
+ line_position = -0.5 + (0.00005 * h_value[0]) - (0.0001 * h_value[2]);;
+ }
+ if(h_value[2] < line_threshold) {
+ line_position = (0.00005 * h_value[1]) - (0.0001 * h_value[3]);
+ }
+ if(h_value[3] < line_threshold) {
+ line_position = 0.5 + (0.00005 * h_value[2]) - (0.0001 * h_value[4]);;
+ }
+ if(h_value[4] < line_threshold) {
+ line_position = 1;
+ if(h_value[3] < line_threshold_hi) line_position = 0.8;
+ }
+ }
+ if(count == 2){
+ if(h_value[0] && h_value[1] < line_threshold){
+ line_found = 1;
+ line_position = -0.6;
+ }
+
+ if(h_value[1] && h_value[2] < line_threshold){
+ line_found = 1;
+ line_position = -0.4;
+ }
+
+ if(h_value[2] && h_value[3] < line_threshold){
+ line_found = 1;
+ line_position = 0.4;
+ }
+
+ if(h_value[3] && h_value[4] < line_threshold){
+ line_found = 1;
+ line_position = 0.6;
+ }
+ }
+}
+
+
+
+void calibrate_base_ir_sensors (void) {
+ short white_background[5];
+ short white_active[5];
+ short black_background[5];
+ short black_active[5];
+ for(int k=0;k<5;k++){
+ white_background[k]=0;
+ black_background[k]=0;
+ white_active[k]=0;
+ black_active[k]=0;
+ }
+ pc.printf("Base IR Calibration\n");
+ display.clear_display();
+ display.write_string("Calibrating base");
+ display.set_position(1,0);
+ display.write_string("IR sensor");
+ wait(0.5);
+ display.clear_display();
+ display.write_string("Place robot on");
+ display.set_position(1,0);
+ display.write_string("white surface");
+ wait(3);
+ display.clear_display();
+ display.write_string("Calibrating base");
+ display.set_position(1,0);
+ display.write_string("IR sensor");
+ wait(0.5);
+ pc.printf("\nWhite Background Results:\n");
+
+ for(int i=0;i<5;i++){
+ wait(0.2);
+ store_background_base_ir_values();
+
+ display.set_position(1,9);
+ display.write_string(".");
+ wait(0.2);
+ store_illuminated_base_ir_values();
+ for(int k=0;k<5;k++){
+ white_background[k]+= get_background_base_ir_value(k);
+ white_active[k] += get_illuminated_base_ir_value(k);
+ }
+ pc.printf("Sample %d 1: %04d-%04d 2: %04d-%04d 3: %04d-%04d 4: %04d-%04d 5: %04d-%04d\n", (i+1),
+ get_background_base_ir_value(0), get_illuminated_base_ir_value(0),
+ get_background_base_ir_value(1), get_illuminated_base_ir_value(1),
+ get_background_base_ir_value(2), get_illuminated_base_ir_value(2),
+ get_background_base_ir_value(3), get_illuminated_base_ir_value(3),
+ get_background_base_ir_value(4), get_illuminated_base_ir_value(4));
+ }
+ for(int k=0;k<5;k++){
+ white_background[k]/=5;
+ white_active[k]/=5;
+ }
+ pc.printf("Mean results 1: %04d-%04d 2: %04d-%04d 3: %04d-%04d 4: %04d-%04d 5: %04d-%04d\n",
+ white_background[0], white_active[0],
+ white_background[1], white_active[1],
+ white_background[2], white_active[2],
+ white_background[3], white_active[3],
+ white_background[4], white_active[4]);
+
+ display.clear_display();
+ display.write_string("Place robot on");
+ display.set_position(1,0);
+ display.write_string("black surface");
+ wait(3);
+
+ display.clear_display();
+ display.write_string("Calibrating base");
+ display.set_position(1,0);
+ display.write_string("IR sensor");
+ wait(0.5);
+ pc.printf("\nBlack Background Results:\n");
+
+ for(int i=0;i<5;i++){
+ wait(0.2);
+
+ store_background_base_ir_values();
+ display.set_position(1,9);
+ display.write_string(".");
+ wait(0.2);
+ store_illuminated_base_ir_values();
+ for(int k=0;k<5;k++){
+ black_background[k]+= get_background_base_ir_value(k);
+ black_active[k] += get_illuminated_base_ir_value(k);
+ }
+ pc.printf("Sample %d 1: %04d-%04d 2: %04d-%04d 3: %04d-%04d 4: %04d-%04d 5: %04d-%04d\n", (i+1),
+ get_background_base_ir_value(0), get_illuminated_base_ir_value(0),
+ get_background_base_ir_value(1), get_illuminated_base_ir_value(1),
+ get_background_base_ir_value(2), get_illuminated_base_ir_value(2),
+ get_background_base_ir_value(3), get_illuminated_base_ir_value(3),
+ get_background_base_ir_value(4), get_illuminated_base_ir_value(4));
+ }
+ for(int k=0;k<5;k++){
+ black_background[k]/=5;
+ black_active[k]/=5;
+ }
+ pc.printf("Mean results 1: %04d-%04d 2: %04d-%04d 3: %04d-%04d 4: %04d-%04d 5: %04d-%04d\n",
+ black_background[0], black_active[0],
+ black_background[1], black_active[1],
+ black_background[2], black_active[2],
+ black_background[3], black_active[3],
+ black_background[4], black_active[4]);
+
+}
+
+
+int get_bearing_from_ir_array (unsigned short * ir_sensor_readings){
+ //out("Getting bearing from array: [%d][%d][%d][%d][%d][%d][%d][%d]\n",ir_sensor_readings[0],ir_sensor_readings[1],ir_sensor_readings[2],ir_sensor_readings[3],ir_sensor_readings[4],ir_sensor_readings[5],ir_sensor_readings[6],ir_sensor_readings[7]);
+
+ float degrees_per_radian = 57.295779513;
+
+ // sin(IR sensor angle) and cos(IR sensor angle) LUT, for all 8 sensors
+ float ir_sensor_sin[8] = {0.382683432, 0.923879533, 0.923879533, 0.382683432, -0.382683432, -0.923879533, -0.923879533, -0.382683432};
+ float ir_sensor_cos[8] = {0.923879533, 0.382683432, -0.382683432, -0.923879533, -0.923879533, -0.382683432, 0.382683432, 0.923879533};
+
+ float sin_sum = 0;
+ float cos_sum = 0;
+
+ for(int i = 0; i < 8; i++)
+ {
+ // Use IR sensor reading to weight bearing vector
+ sin_sum += ir_sensor_sin[i] * ir_sensor_readings[i];
+ cos_sum += ir_sensor_cos[i] * ir_sensor_readings[i];
+ }
+
+ float bearing = atan2(sin_sum, cos_sum); // Calculate vector towards IR light source
+ bearing *= degrees_per_radian; // Convert to degrees
+
+ //out("Sin sum:%f Cos sum:%f Bearing:%f\n",sin_sum,cos_sum,bearing);
+
+ return (int) bearing;
+}
+