James O'Keeffe / Mbed 2 deprecated BeaconDemo_RobotCodeNew

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Dependencies:   mbed

Fork of BeaconDemo_RobotCode by Science Memeseum

beacon.cpp@9:085e090e1ec1, 2015-10-26 (annotated)

Committer:
jah128
Date:
Mon Oct 26 11:16:05 2015 +0000
Revision:
9:085e090e1ec1
Parent:
7:ef9ab01b9e26
Child:
10:1b09d4bb847b
Fork for variable frequency beacon

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UserRevisionLine numberNew contents of line
jah128 6:ff3c66f7372b 1 /// PsiSwarm Beautiful Meme Project Source Code
jah128 6:ff3c66f7372b 2 /// Version 0.1
jah128 6:ff3c66f7372b 3 /// James Hilder, Alan Millard, Homero Elizondo, Jon Timmis
jah128 6:ff3c66f7372b 4 /// University of York
jah128 6:ff3c66f7372b 5
jah128 6:ff3c66f7372b 6 // Beacon.cpp - Functions for detecting the beacon and taking IR readings of the robots
jah128 6:ff3c66f7372b 7
jah128 6:ff3c66f7372b 8 #include "psiswarm.h"
jah128 9:085e090e1ec1 9 #include "main.h"
jah128 6:ff3c66f7372b 10
jah128 6:ff3c66f7372b 11 int pulse_step = 1; //Pulse-step corresponds to which timeslot (0-9) is currently active, where beacon=0 and robots=2-8
jah128 6:ff3c66f7372b 12 int low_threshold; //Set to be 2x mean background IR
jah128 6:ff3c66f7372b 13 int beacon_threshold; //Set to be 4x mean background IR
jah128 6:ff3c66f7372b 14 unsigned short ir_sensor_data[9][8]; // The raw sensor data from all 9x 50ms sample windows
jah128 6:ff3c66f7372b 15 Ticker ir_sample_ticker; // Ticker for the IR data sampling and processing; runs every 50ms in middle of timeslot
jah128 6:ff3c66f7372b 16 Ticker ir_emitter_ticker; // Ticker for turning on the IR emitters; runs every 50ms near start of timeslot
jah128 6:ff3c66f7372b 17 Timeout ir_emitter_timeout; // Timeout for turning off the IR emitters after 40ms
jah128 6:ff3c66f7372b 18 Timer beacon_debug_timer; // Timer for debug information only [remove later?]
jah128 6:ff3c66f7372b 19
jah128 6:ff3c66f7372b 20
jah128 6:ff3c66f7372b 21
jah128 9:085e090e1ec1 22 /// The locate beacon function samples the IR radiation from all 8 side sensors over a period of 1 second in [BEACON_PERIOD / 2.5] (20ms) blocks.
jah128 6:ff3c66f7372b 23 /// The infrared beacon is set to give a 50ms burst of IR every 500ms. We should thus see in the sampled radiation 2 blocks
jah128 6:ff3c66f7372b 24 /// of samples, 2 or 3 samples in duration, when a significant peak occurs; the blocks should be 25 samples apart.
jah128 6:ff3c66f7372b 25 void locate_beacon()
jah128 6:ff3c66f7372b 26 {
jah128 9:085e090e1ec1 27 int sample_period = (BEACON_PERIOD * 2) / 5;
jah128 6:ff3c66f7372b 28 out("1) Searching for IR beacon...");
jah128 6:ff3c66f7372b 29 unsigned short samples[50][9];
jah128 6:ff3c66f7372b 30 Timer beacon_timer;
jah128 6:ff3c66f7372b 31 beacon_timer.start();
jah128 6:ff3c66f7372b 32 int offset = 0;
jah128 6:ff3c66f7372b 33 //This loop samples the background IR values at 50Hz for 1 second and stores in an array
jah128 6:ff3c66f7372b 34 for(int i=0; i<50; i++) {
jah128 6:ff3c66f7372b 35 store_background_raw_ir_values ();
jah128 9:085e090e1ec1 36 if(i%2 == 0){
jah128 9:085e090e1ec1 37 set_center_led(1, 0.5);
jah128 9:085e090e1ec1 38 set_leds(0xAA,0x55);
jah128 9:085e090e1ec1 39 }else{
jah128 9:085e090e1ec1 40 set_center_led(2, 0.5);
jah128 9:085e090e1ec1 41 set_leds(0x55,0xAA);
jah128 9:085e090e1ec1 42 }
jah128 6:ff3c66f7372b 43 samples[i][8]=0;
jah128 6:ff3c66f7372b 44 for(int j=0; j<8; j++) {
jah128 6:ff3c66f7372b 45 samples[i][j] = get_background_raw_ir_value(j);
jah128 6:ff3c66f7372b 46 samples[i][8] += get_background_raw_ir_value(j);
jah128 6:ff3c66f7372b 47 }
jah128 9:085e090e1ec1 48 offset+=sample_period;
jah128 6:ff3c66f7372b 49 while(beacon_timer.read_us() < offset) {}
jah128 6:ff3c66f7372b 50 }
jah128 6:ff3c66f7372b 51
jah128 6:ff3c66f7372b 52 //Print values: for testing [comment out]
jah128 6:ff3c66f7372b 53 /*
jah128 6:ff3c66f7372b 54 for(int i=0; i<50; i++) {
jah128 6:ff3c66f7372b 55 out("IR %d:",i);
jah128 6:ff3c66f7372b 56 for(int j=0; j<8; j++) {
jah128 6:ff3c66f7372b 57 out("[%d:%d]",j,samples[i][j]);
jah128 6:ff3c66f7372b 58 }
jah128 6:ff3c66f7372b 59 out(" [SUM:%d]\n",samples[i][8]);
jah128 6:ff3c66f7372b 60 }
jah128 6:ff3c66f7372b 61 */
jah128 6:ff3c66f7372b 62
jah128 6:ff3c66f7372b 63 //Bubble sort sums to find (6) highest values
jah128 6:ff3c66f7372b 64 unsigned short sorted_array[50];
jah128 6:ff3c66f7372b 65 for(int i=0; i<50; i++) {
jah128 6:ff3c66f7372b 66 sorted_array[i]=samples[i][8];
jah128 6:ff3c66f7372b 67 }
jah128 6:ff3c66f7372b 68 for (int c = 0 ; c < 49; c++) {
jah128 6:ff3c66f7372b 69 for (int d = 0 ; d < (50-c-1); d++) {
jah128 6:ff3c66f7372b 70 if (sorted_array[d] > sorted_array[d+1]) {
jah128 6:ff3c66f7372b 71 unsigned short swap = sorted_array[d];
jah128 6:ff3c66f7372b 72 sorted_array[d] = sorted_array[d+1];
jah128 6:ff3c66f7372b 73 sorted_array[d+1] = swap;
jah128 6:ff3c66f7372b 74 }
jah128 6:ff3c66f7372b 75 }
jah128 6:ff3c66f7372b 76 }
jah128 6:ff3c66f7372b 77
jah128 6:ff3c66f7372b 78 //Print sorted values: for testing [comment out]
jah128 6:ff3c66f7372b 79 /*
jah128 6:ff3c66f7372b 80 out("Sorted values:");
jah128 6:ff3c66f7372b 81 for (int c = 0 ; c < 50 ; c++ ) {
jah128 6:ff3c66f7372b 82 out("%d", sorted_array[c]);
jah128 6:ff3c66f7372b 83 if(c<49)out(",");
jah128 6:ff3c66f7372b 84 }
jah128 6:ff3c66f7372b 85 out("\n");
jah128 6:ff3c66f7372b 86 */
jah128 6:ff3c66f7372b 87
jah128 6:ff3c66f7372b 88 // Calculate mean background sum value by looking at 44 lowest sum values
jah128 6:ff3c66f7372b 89 int background_mean = 0;
jah128 6:ff3c66f7372b 90 for(int i=0;i<44;i++)background_mean += sorted_array[i];
jah128 6:ff3c66f7372b 91 background_mean /= 44;
jah128 6:ff3c66f7372b 92
jah128 6:ff3c66f7372b 93 //out("Background mean value: %d\n",background_mean);
jah128 6:ff3c66f7372b 94
jah128 6:ff3c66f7372b 95 //Our beacon threshold will be 4x the background mean value; find all instances where this occurs
jah128 6:ff3c66f7372b 96 low_threshold = background_mean * 2;
jah128 6:ff3c66f7372b 97 beacon_threshold = background_mean * 4;
jah128 6:ff3c66f7372b 98 char beacon_detected_indices[50];
jah128 6:ff3c66f7372b 99 for(int i=0;i<50;i++){
jah128 6:ff3c66f7372b 100 if(samples[i][8] > beacon_threshold) beacon_detected_indices[i]=1;
jah128 6:ff3c66f7372b 101 else beacon_detected_indices[i]=0;
jah128 6:ff3c66f7372b 102 }
jah128 6:ff3c66f7372b 103 //Count and display matches
jah128 6:ff3c66f7372b 104 int beacon_detected_count = 0;
jah128 9:085e090e1ec1 105 //char output_string[251] = "";
jah128 6:ff3c66f7372b 106 for(int i=0;i<50;i++){
jah128 6:ff3c66f7372b 107 if(beacon_detected_indices[i] == 1){
jah128 6:ff3c66f7372b 108 beacon_detected_count++;
jah128 9:085e090e1ec1 109 // char index_string[6];
jah128 9:085e090e1ec1 110 // sprintf(index_string,"[%d],",i);
jah128 9:085e090e1ec1 111 // strcat(output_string,index_string);
jah128 6:ff3c66f7372b 112 }
jah128 6:ff3c66f7372b 113 }
jah128 6:ff3c66f7372b 114 //out("%d samples are above threshold:%s\n",beacon_detected_count,output_string);
jah128 6:ff3c66f7372b 115
jah128 6:ff3c66f7372b 116 //We will use this array to store average values for each sensor when the beacon is detected
jah128 6:ff3c66f7372b 117 unsigned short beacon_averages[8];
jah128 6:ff3c66f7372b 118 char beacon_averages_count = 0;
jah128 6:ff3c66f7372b 119 for(int i=0;i<8;i++)beacon_averages[i]=0;
jah128 6:ff3c66f7372b 120
jah128 6:ff3c66f7372b 121 //Now determine if the beacon is correctly found: must adhere to a set of rules
jah128 6:ff3c66f7372b 122 //Firstly, we should have not less than 4 and not more than 6 positive matches
jah128 6:ff3c66f7372b 123 if(beacon_detected_count>3 && beacon_detected_count<7){
jah128 6:ff3c66f7372b 124 // Now verify that the positive samples are in valid places...
jah128 6:ff3c66f7372b 125 // Find first positive sample
jah128 6:ff3c66f7372b 126 int first_index = 0;
jah128 6:ff3c66f7372b 127 //out("Here\n",first_index);
jah128 6:ff3c66f7372b 128
jah128 6:ff3c66f7372b 129 while(beacon_detected_indices[first_index]==0)first_index ++;
jah128 6:ff3c66f7372b 130
jah128 6:ff3c66f7372b 131 //out("First index:%d\n",first_index);
jah128 6:ff3c66f7372b 132
jah128 6:ff3c66f7372b 133
jah128 6:ff3c66f7372b 134 // Check if first index is zero: if so, we need to check index 49 (and 48) to see if they are also high
jah128 6:ff3c66f7372b 135 if(first_index == 0){
jah128 6:ff3c66f7372b 136 if(beacon_detected_indices[49]>0)first_index = 49;
jah128 6:ff3c66f7372b 137 if(beacon_detected_indices[48]>0)first_index = 48;
jah128 6:ff3c66f7372b 138 }
jah128 6:ff3c66f7372b 139
jah128 6:ff3c66f7372b 140 beacon_averages_count++;
jah128 6:ff3c66f7372b 141 for(int i=0;i<8;i++){beacon_averages[i]+=samples[first_index][i];}
jah128 6:ff3c66f7372b 142
jah128 6:ff3c66f7372b 143 // Now count the length of the 'block' of positive hits: must be equal to 2 or 3
jah128 6:ff3c66f7372b 144 char block_length = 1;
jah128 6:ff3c66f7372b 145 int end_index = first_index + 1;
jah128 6:ff3c66f7372b 146 if(end_index == 50) end_index = 0;
jah128 6:ff3c66f7372b 147 while(beacon_detected_indices[end_index]>0){
jah128 6:ff3c66f7372b 148 beacon_averages_count++;
jah128 6:ff3c66f7372b 149 for(int i=0;i<8;i++){beacon_averages[i]+=samples[end_index][i];}
jah128 6:ff3c66f7372b 150 block_length ++;
jah128 6:ff3c66f7372b 151 end_index ++;
jah128 6:ff3c66f7372b 152 if(end_index == 50) end_index = 0;
jah128 6:ff3c66f7372b 153 }
jah128 6:ff3c66f7372b 154 if(block_length==2 || block_length == 3){
jah128 6:ff3c66f7372b 155 //We have found the first correct block and it is valid; now calculate its mid-point and check that the second block is also present 500ms later
jah128 6:ff3c66f7372b 156 float mid_point;
jah128 6:ff3c66f7372b 157 char second_block_okay = 0;
jah128 6:ff3c66f7372b 158 if(block_length == 2){
jah128 6:ff3c66f7372b 159 mid_point = first_index + 0.5;
jah128 6:ff3c66f7372b 160 char second_block_low = first_index + 25;
jah128 6:ff3c66f7372b 161 char second_block_high = first_index + 26;
jah128 6:ff3c66f7372b 162 if(second_block_low > 49) second_block_low -= 50;
jah128 6:ff3c66f7372b 163 if(second_block_high > 49) second_block_high -= 50;
jah128 6:ff3c66f7372b 164 beacon_averages_count+=2;
jah128 6:ff3c66f7372b 165 for(int i=0;i<8;i++){beacon_averages[i]+=samples[second_block_low][i]+samples[second_block_high][i];}
jah128 6:ff3c66f7372b 166 if(beacon_detected_indices[second_block_low]>0 && beacon_detected_indices[second_block_high]>0) second_block_okay = 1;
jah128 6:ff3c66f7372b 167 }
jah128 6:ff3c66f7372b 168 if(block_length == 3){
jah128 6:ff3c66f7372b 169 mid_point = first_index + 1;
jah128 6:ff3c66f7372b 170 if(mid_point == 50) mid_point = 0;
jah128 6:ff3c66f7372b 171 char second_block_single = first_index + 26;
jah128 6:ff3c66f7372b 172 if(second_block_single > 49) second_block_single -= 50;
jah128 6:ff3c66f7372b 173 beacon_averages_count++;
jah128 6:ff3c66f7372b 174 for(int i=0;i<8;i++){beacon_averages[i]+=samples[second_block_single][i];}
jah128 6:ff3c66f7372b 175 if(beacon_detected_indices[second_block_single]>0) second_block_okay = 1;
jah128 6:ff3c66f7372b 176 }
jah128 6:ff3c66f7372b 177 if(second_block_okay >0){
jah128 6:ff3c66f7372b 178 beacon_found = 1;
jah128 6:ff3c66f7372b 179 beacon_heading = get_bearing_from_ir_array(beacon_averages);
jah128 6:ff3c66f7372b 180 out("Found at %d degrees\n",beacon_heading);
jah128 6:ff3c66f7372b 181 //for(int i=0;i<8;i++){
jah128 6:ff3c66f7372b 182 // beacon_averages[i] /= beacon_averages_count;
jah128 6:ff3c66f7372b 183 // out("[%d]",beacon_averages[i]);
jah128 6:ff3c66f7372b 184 //}
jah128 6:ff3c66f7372b 185 out("2) Synchronising...\n");
jah128 6:ff3c66f7372b 186 // Calculate the offset to the expected start of the next beacon pulse
jah128 9:085e090e1ec1 187 int microseconds_offset = (sample_period * mid_point) - sample_period - (sample_period / 4);
jah128 6:ff3c66f7372b 188 //out("MS Offset:%d Midpoint:%f\n Current Time:%d\n",microseconds_offset,mid_point,beacon_timer.read_us());
jah128 9:085e090e1ec1 189 int cycle_period = (BEACON_PERIOD * 10);
jah128 9:085e090e1ec1 190 if(microseconds_offset < 0) microseconds_offset += cycle_period;
jah128 6:ff3c66f7372b 191 //If we have missed the start of the beacon this cycle, wait until the next cycle
jah128 9:085e090e1ec1 192 while(beacon_timer.read_us()% (cycle_period) > microseconds_offset){};
jah128 6:ff3c66f7372b 193 //Now wait until the start of the beacon pulse
jah128 9:085e090e1ec1 194 while(beacon_timer.read_us()% (cycle_period) < microseconds_offset){};
jah128 6:ff3c66f7372b 195 /*
jah128 6:ff3c66f7372b 196 out("Now:%d",beacon_timer.read_us());
jah128 6:ff3c66f7372b 197 Timer test_timer;
jah128 6:ff3c66f7372b 198 test_timer.start();
jah128 6:ff3c66f7372b 199 for(int i=0;i<50;i++){
jah128 6:ff3c66f7372b 200 store_background_raw_ir_values ();
jah128 6:ff3c66f7372b 201 out("Time %d: %d\n",test_timer.read_ms(),get_background_raw_ir_value(2));
jah128 6:ff3c66f7372b 202 while(test_timer.read_ms() % 10 < 9){};
jah128 6:ff3c66f7372b 203 }
jah128 6:ff3c66f7372b 204 */
jah128 6:ff3c66f7372b 205 }else{
jah128 6:ff3c66f7372b 206 beacon_found = 0;
jah128 9:085e090e1ec1 207 out("Beacon not found: a matching second block %dms after first block not detected\n",(BEACON_PERIOD / 100));
jah128 6:ff3c66f7372b 208 }
jah128 6:ff3c66f7372b 209 }else{
jah128 6:ff3c66f7372b 210 beacon_found = 0;
jah128 6:ff3c66f7372b 211 if(block_length == 1) out("Beacon not found: a single sample [%d] was high but not its neighbours\n",first_index);
jah128 6:ff3c66f7372b 212 if(block_length > 3) out("Beacon not found: a block of %d high samples was detected\n",block_length);
jah128 6:ff3c66f7372b 213 }
jah128 6:ff3c66f7372b 214 } else {
jah128 6:ff3c66f7372b 215 beacon_found = 0;
jah128 7:ef9ab01b9e26 216 if(beacon_detected_count > 6) out("Beacon not found: too many high samples [%d]\n",beacon_detected_count);
jah128 6:ff3c66f7372b 217 else out("Beacon not found: too few high samples [%d]\n",beacon_detected_count);
jah128 6:ff3c66f7372b 218 }
jah128 9:085e090e1ec1 219 if(beacon_found == 0){
jah128 9:085e090e1ec1 220 set_leds(0x00,0x00);
jah128 9:085e090e1ec1 221 set_center_led(1, 1);
jah128 9:085e090e1ec1 222 display.clear_display();
jah128 9:085e090e1ec1 223 display.set_position(0,0);
jah128 9:085e090e1ec1 224 display.write_string("BEACON NOT FOUND");
jah128 9:085e090e1ec1 225 }
jah128 6:ff3c66f7372b 226 }
jah128 6:ff3c66f7372b 227
jah128 6:ff3c66f7372b 228 // The start_infrared_timers() function is called as soon as the beacon has been detected and synchronised to
jah128 6:ff3c66f7372b 229 // It launches 2 tickers at offset times; the first is responsible for turning the robots IR emitters on in its proper timeslot
jah128 6:ff3c66f7372b 230 // The other reads the values given from the IR sensor in the middle of each timeslot and processes that information in the final timeslot
jah128 6:ff3c66f7372b 231 void start_infrared_timers()
jah128 6:ff3c66f7372b 232 {
jah128 6:ff3c66f7372b 233 // At this point we should be exactly at the start of a beacon cycle.
jah128 6:ff3c66f7372b 234 // We want the emitter ticker to start in approx 5ms (this will let us set a 40ms pulse)
jah128 6:ff3c66f7372b 235 // We want the sample ticker to start in approx 25ms (this will let us sample in the middle each step
jah128 6:ff3c66f7372b 236 out("3) Starting TDMA infrared timers\n");
jah128 6:ff3c66f7372b 237 beacon_debug_timer.start();
jah128 9:085e090e1ec1 238 wait_us(BEACON_PERIOD / 10);
jah128 9:085e090e1ec1 239 ir_emitter_ticker.attach_us(emitter_ticker_block,BEACON_PERIOD);
jah128 9:085e090e1ec1 240 wait_us(((BEACON_PERIOD * 4) / 10)); //Wait for middle of pulse
jah128 9:085e090e1ec1 241 ir_sample_ticker.attach_us(sample_ticker_block,BEACON_PERIOD);
jah128 6:ff3c66f7372b 242 }
jah128 6:ff3c66f7372b 243
jah128 6:ff3c66f7372b 244
jah128 6:ff3c66f7372b 245 //Return the max value in IR array
jah128 6:ff3c66f7372b 246 unsigned short get_highest_sample(unsigned short * ir_array){
jah128 6:ff3c66f7372b 247 unsigned short highest = 0;
jah128 6:ff3c66f7372b 248 for(int i=0;i<8;i++){
jah128 6:ff3c66f7372b 249 if(ir_array[i]>highest) highest=ir_array[i];
jah128 6:ff3c66f7372b 250 }
jah128 6:ff3c66f7372b 251 return highest;
jah128 6:ff3c66f7372b 252 }
jah128 6:ff3c66f7372b 253
jah128 6:ff3c66f7372b 254 //Return the sum total of IR array
jah128 6:ff3c66f7372b 255 unsigned short get_sum_sample(unsigned short * ir_array){
jah128 6:ff3c66f7372b 256 unsigned short sum = 0;
jah128 6:ff3c66f7372b 257 for(int i=0;i<8;i++){
jah128 6:ff3c66f7372b 258 sum+=ir_array[i];
jah128 6:ff3c66f7372b 259 }
jah128 6:ff3c66f7372b 260 return sum;
jah128 6:ff3c66f7372b 261 }
jah128 6:ff3c66f7372b 262
jah128 6:ff3c66f7372b 263 //The emitter_ticker_block function runs every 50ms and turns the IR emitters on when pulse_step-1 matches the robot ID
jah128 6:ff3c66f7372b 264 //It then starts a timeout to run emitter_timeout_block after 40ms, which turns off the emitters
jah128 6:ff3c66f7372b 265 void emitter_ticker_block(){
jah128 6:ff3c66f7372b 266 //If the time-step (-1) equals my ID, turn on my emitters for 40ms
jah128 6:ff3c66f7372b 267 if(pulse_step-1 == robot_id){
jah128 6:ff3c66f7372b 268 IF_set_IR_emitter_output(0, 1);
jah128 6:ff3c66f7372b 269 IF_set_IR_emitter_output(1, 1);
jah128 9:085e090e1ec1 270 ir_emitter_timeout.attach_us(emitter_timeout_block,(BEACON_PERIOD * 8)/10);
jah128 6:ff3c66f7372b 271 }
jah128 6:ff3c66f7372b 272 }
jah128 6:ff3c66f7372b 273
jah128 6:ff3c66f7372b 274 //Turn off the emitters
jah128 6:ff3c66f7372b 275 void emitter_timeout_block(){
jah128 6:ff3c66f7372b 276 //Turn off IR emitters
jah128 6:ff3c66f7372b 277 IF_set_IR_emitter_output(0, 0);
jah128 6:ff3c66f7372b 278 IF_set_IR_emitter_output(1, 0);
jah128 6:ff3c66f7372b 279 }
jah128 6:ff3c66f7372b 280
jah128 6:ff3c66f7372b 281 //The function sample_ticker_block() is called every 50ms, and should run close to the middle of every timeslot
jah128 6:ff3c66f7372b 282 //There are 10 time slots in each 500ms period
jah128 6:ff3c66f7372b 283 //Slot 0 is when the beacon is flashing
jah128 6:ff3c66f7372b 284 //Slot 1 should be IR-free and is used to measure background IR data, stored in background_sensor_data[]
jah128 6:ff3c66f7372b 285 //Slot 2-8 are for the 7 robots; slot-1 = robot_id
jah128 6:ff3c66f7372b 286 //In slot 9, the robot processes the data [and doesn't store and new readings]
jah128 6:ff3c66f7372b 287 //It checks if the beacon is visible, if any robots are, calculates their bearings if they are, and transfers the background and active IR data for the robot
jah128 6:ff3c66f7372b 288 void sample_ticker_block(){
jah128 6:ff3c66f7372b 289 //If we are in time-step 0 to 8, store the background data in an array
jah128 6:ff3c66f7372b 290 if(pulse_step < 9){
jah128 6:ff3c66f7372b 291 store_background_raw_ir_values ();
jah128 6:ff3c66f7372b 292 for(int i=0;i<8;i++)ir_sensor_data[pulse_step][i]=get_background_raw_ir_value(i);
jah128 6:ff3c66f7372b 293 }else{
jah128 6:ff3c66f7372b 294 //If not, process the data
jah128 6:ff3c66f7372b 295 for(int i=0;i<9;i++){
jah128 6:ff3c66f7372b 296 unsigned short sum = get_sum_sample(ir_sensor_data[i]);
jah128 6:ff3c66f7372b 297 unsigned short highest = get_highest_sample(ir_sensor_data[i]);
jah128 6:ff3c66f7372b 298 //Check if beacon is visible
jah128 6:ff3c66f7372b 299 if(i==0){
jah128 6:ff3c66f7372b 300 if(sum > beacon_threshold){
jah128 6:ff3c66f7372b 301 beacon_found = 1;
jah128 6:ff3c66f7372b 302 beacon_heading = get_bearing_from_ir_array (ir_sensor_data[0]);
jah128 6:ff3c66f7372b 303 }else beacon_found = 0;
jah128 6:ff3c66f7372b 304 //out("Beacon sum:%d 0:%d 4:%d\n",sum,ir_sensor_data[0][0],ir_sensor_data[0][4]);
jah128 6:ff3c66f7372b 305 }
jah128 6:ff3c66f7372b 306 if(i==1){
jah128 6:ff3c66f7372b 307 for(int j=0;j<8;j++)background_sensor_data[j]=ir_sensor_data[1][j];
jah128 6:ff3c66f7372b 308 }
jah128 6:ff3c66f7372b 309 if(i>1){
jah128 6:ff3c66f7372b 310 char test_robot = i-1;
jah128 6:ff3c66f7372b 311 if(test_robot == robot_id){
jah128 6:ff3c66f7372b 312 for(int j=0;j<8;j++)reflected_sensor_data[j]=ir_sensor_data[i][j];
jah128 6:ff3c66f7372b 313 }else{
jah128 6:ff3c66f7372b 314 if(sum > low_threshold){
jah128 6:ff3c66f7372b 315 robots_found[test_robot] = 1;
jah128 7:ef9ab01b9e26 316 //Debug--
jah128 7:ef9ab01b9e26 317 //out("Robot %d: [%d][%d][%d][%d][%d][%d][%d][%d]\n",test_robot,ir_sensor_data[i][0],ir_sensor_data[i][1],ir_sensor_data[i][2],ir_sensor_data[i][3],ir_sensor_data[i][4],ir_sensor_data[i][5],ir_sensor_data[i][6],ir_sensor_data[i][7]);
jah128 6:ff3c66f7372b 318 robots_heading[test_robot] = get_bearing_from_ir_array (ir_sensor_data[i]);
jah128 6:ff3c66f7372b 319 robots_distance[test_robot] = highest;
jah128 6:ff3c66f7372b 320 }else robots_found[test_robot] = 0;
jah128 6:ff3c66f7372b 321 }
jah128 6:ff3c66f7372b 322 }
jah128 6:ff3c66f7372b 323 }
jah128 6:ff3c66f7372b 324 display_ir_readings();
jah128 6:ff3c66f7372b 325 }
jah128 6:ff3c66f7372b 326 //Increment pulse step
jah128 6:ff3c66f7372b 327 pulse_step++;
jah128 6:ff3c66f7372b 328 if(pulse_step == 10) pulse_step = 0;
jah128 6:ff3c66f7372b 329 }
jah128 6:ff3c66f7372b 330
jah128 6:ff3c66f7372b 331
jah128 6:ff3c66f7372b 332 //Testing function to print out lines showing what robot can currently see in terms of beacon, other robots and obstacles
jah128 6:ff3c66f7372b 333 void display_ir_readings()
jah128 6:ff3c66f7372b 334 {
jah128 6:ff3c66f7372b 335 out("____________________________________\nInfrared Detection at %d ms\n",beacon_debug_timer.read_ms());
jah128 6:ff3c66f7372b 336 if(beacon_found==1){
jah128 6:ff3c66f7372b 337 out("Beacon detected at %d degrees\n",beacon_heading);
jah128 6:ff3c66f7372b 338 }
jah128 6:ff3c66f7372b 339 for(int j=1;j<8;j++){
jah128 6:ff3c66f7372b 340 if(robots_found[j])out("Robot %d detected at %d degrees, %d distance\n",j,robots_heading[j],robots_distance[j]);
jah128 6:ff3c66f7372b 341 }
jah128 6:ff3c66f7372b 342 out("Reflected values:");
jah128 6:ff3c66f7372b 343 for(int i=0;i<8;i++){
jah128 6:ff3c66f7372b 344 out("[%d,%d]",i,reflected_sensor_data[i]);
jah128 6:ff3c66f7372b 345 }
jah128 6:ff3c66f7372b 346 out("\nBackground values:");
jah128 6:ff3c66f7372b 347 for(int i=0;i<8;i++){
jah128 6:ff3c66f7372b 348 out("[%d,%d]",i,background_sensor_data[i]);
jah128 6:ff3c66f7372b 349 }
jah128 6:ff3c66f7372b 350 out("\n\n");
jah128 9:085e090e1ec1 351 }
jah128 9:085e090e1ec1 352
jah128 9:085e090e1ec1 353 //Returns a 0 if turn is likely to complete in a single timestep, 1 if it is beyond range for single timestep and 2 if the beacon is not found so bearing unknown
jah128 9:085e090e1ec1 354 char turn_to_bearing(int bearing)
jah128 9:085e090e1ec1 355 {
jah128 9:085e090e1ec1 356 if(beacon_found == 0){
jah128 9:085e090e1ec1 357 out("Beacon not found: cannot turn to specific bearing");
jah128 9:085e090e1ec1 358 return 2;
jah128 9:085e090e1ec1 359 }else{
jah128 9:085e090e1ec1 360 //First calculate the bearing using the angle of beacon relative to robot
jah128 9:085e090e1ec1 361 int current_bearing = 360 - beacon_heading;
jah128 9:085e090e1ec1 362 //Now work out turn needed to face intended heading
jah128 9:085e090e1ec1 363 int target_turn = (bearing - current_bearing) % 360;
jah128 9:085e090e1ec1 364 if(target_turn > 180) target_turn -= 360;
jah128 9:085e090e1ec1 365 if(target_turn < -180) target_turn += 360;
jah128 9:085e090e1ec1 366 //We can't reliably turn more than 280 degrees per second, so set a limit for the turn to that
jah128 9:085e090e1ec1 367 char beyond_limit = 0;
jah128 9:085e090e1ec1 368 int turn_limit = BEACON_PERIOD / 358;
jah128 9:085e090e1ec1 369 if(target_turn > turn_limit) {target_turn = turn_limit; beyond_limit = 1;};
jah128 9:085e090e1ec1 370 if(target_turn < -turn_limit) {target_turn = -turn_limit; beyond_limit = 1;};
jah128 9:085e090e1ec1 371 out("Turning %d degrees\n",target_turn);
jah128 9:085e090e1ec1 372 time_based_turn_degrees(1, target_turn,1);
jah128 9:085e090e1ec1 373 return beyond_limit;
jah128 9:085e090e1ec1 374 }
jah128 6:ff3c66f7372b 375 }