Diff: main.cpp

Revision:

48:78310b56de00

Parent:

47:eeed074999ab

--- a/main.cpp	Tue Mar 19 18:25:39 2019 +0000
+++ b/main.cpp	Sun Mar 24 15:37:28 2019 +0000
@@ -7,13 +7,13 @@
  
 #define range1_addr         (0x56)
 #define range2_addr         (0x60)
-#define range1_XSHUT        p15
-#define range2_XSHUT        p16
+#define range1_XSHUT        p16
+#define range2_XSHUT        p15
 #define VL53L0_I2C_SDA      p30 
 #define VL53L0_I2C_SCL      p7  
 #define TIME_SCALE          3 // sensors activated every 100ms * TIME_SCALE = 0.3 seconds
 #define DIST_MIN            20 // PROD
-#define DIST_MAX            100 // PROD
+#define DIST_MAX            120 // PROD
 //#define DIST_MIN            0 // DEV
 //#define DIST_MAX            22 // DEV
 //#define TIMESTAMP_FREQ      3000 // PROD: time granularity is 100ms * TIMESTAMP_FREQ = 5 minutes
@@ -41,7 +41,7 @@
 int packet_queue[4000] = {0};
 int packet_queue_index = 2;
 int current_index = 0, send_count = 0, triple_send_count = 0;
-
+ 
 const static int cw = 20 / TIME_SCALE;
 const static int time_cycle = TIMESTAMP_FREQ / TIME_SCALE;
 const static int maximum_time = MAX_TIME / TIMESTAMP_FREQ;
@@ -59,7 +59,8 @@
  
 HeartRateService         *hrService;
 uint8_t hrmCounter = 0; 
-
+ 
+// converts distance to cm
 int format_dist(int distance) {
    int result;
    if (distance > 2550)
@@ -68,7 +69,9 @@
       result = distance/10;
    return result; 
 }
-
+ 
+// starts the clock after one sensor was triggered: the next must be triggered 
+// within 2 seconds for a step to be counted
 void check_for_countdown(bool countdown_triggered) {
     if (countdown_triggered) {
         ::countdown--;
@@ -78,13 +81,14 @@
     }
 }
 
-
+// needed for the stalling of the queue after the first 4 packets are transmitted:
+// pads queue with "fake" packets that will not be transmitted
 void optimize_transmissions(int packet_queue[]) {
     for (int count = 4; count < 12; count++) {
         packet_queue[count] = 1;
     }
 }
-
+ 
 void dec_to_bin(int decimal, int bin[]) {
     int temp;
     // encoding little-endian
@@ -93,7 +97,7 @@
         bin[i] = temp&1;
     }
 }
-
+ 
 int bin_to_dec(int binary) {
     int rem, temp, dec = 0, b = 1;
     temp = binary;
@@ -107,6 +111,7 @@
     return dec;
 }
 
+// creates the encoding that fits all required info into 2 bytes
 void encode_bin(int direction, int time, int encoding[]) {
     time = time % maximum_time;
     int bin_timestamp[11] = {0};
@@ -116,7 +121,7 @@
     // sending as 2 messages; designating them with 0 (1st part) and 1 (2nd part)
     encoding [8] = 1;
     encoding [0] = 0;
-
+ 
     // used to send the current time when Bluetooth connection established
     if (direction == -1) {
         encoding[15] = 1;
@@ -143,7 +148,8 @@
         }
      }
 }
-
+ 
+// converts the binary encoding back into 2 byte-sized packets
 void create_packets(int encoding[], double& packet1, double& packet2) {
     double binary1 = 0, binary2 = 0;
     for (int i = 0; i < 8; i++) {
@@ -153,14 +159,15 @@
     packet1 = bin_to_dec(binary1);
     packet2 = bin_to_dec(binary2);
 }
-
+ 
 void send_packet() {     
     hrmCounter = packet_queue[current_index];
     hrService->updateHeartRate(hrmCounter);
-    printf("sent packet %i\n", hrmCounter);
+    printf("sent packet %i\r\n", hrmCounter);
     ::current_index++;
 }
-
+ 
+// steps are added to a queue to be sent as soon as the gateway connects
 void enqueue_packet(int direction, int time, int packet_queue[], int priority) { 
     int encoding [16] = {0};
     encode_bin(direction, time, encoding);
@@ -173,8 +180,8 @@
         packet_queue[0] = p1;
         packet_queue[1] = p2;
     
-        printf("sudo enqueued packet %i\n",  packet_queue[0]);
-        printf("sudo enqueued packet %i\n",  packet_queue[1]);
+        printf("sudo enqueued packet %i\r\n",  packet_queue[0]);
+        printf("sudo enqueued packet %i\r\n",  packet_queue[1]);
     } else {        
         if (packet_queue_index == 4) {
             ::packet_queue_index = 12;
@@ -182,24 +189,28 @@
         packet_queue[packet_queue_index] = p1;
         packet_queue[packet_queue_index + 1] = p2;
     
-        printf("enqueued packet %i\n",  packet_queue[packet_queue_index]);
-        printf("enqueued packet %i\n",  packet_queue[packet_queue_index+1]);
+        printf("enqueued packet %i\r\n",  packet_queue[packet_queue_index]);
+        printf("enqueued packet %i\r\n",  packet_queue[packet_queue_index+1]);
     
         ::packet_queue_index += 2;
     }
 }
-
+ 
+// the end of the queue transmission is signalled so gateway users know
+// when it is safe to disconnect
 void enqueue_transmission_break() {
     int p1 = 0;
     int p2 = 0;
     
     packet_queue[packet_queue_index] = p1;
     packet_queue[packet_queue_index + 1] = p2;
-    printf("enqueued transmission breaks %i and %i\n", packet_queue[packet_queue_index], packet_queue[packet_queue_index+1]);
+    printf("enqueued transmission breaks %i and %i\r\n", packet_queue[packet_queue_index], packet_queue[packet_queue_index+1]);
     
     ::packet_queue_index += 2;
 }
-
+ 
+// adapted from code found at https://os.mbed.com/users/jkjk010695/code/Multi_VL53L0X/
+// checks sensor readings to determine whether a step has been taken
 void check_for_step(int direction, int status, int dist, DigitalOut led, bool& this_countdown_triggered, 
                     bool& other_countdown_triggered, bool& this_range_triggered, bool& other_range_triggered,
                     int packet_queue[]) {
@@ -212,7 +223,7 @@
                 this_countdown_triggered = true;
                 ::countdown = cw;
             } else if (other_countdown_triggered && !this_range_triggered) {
-                printf("STEP %i DETECTED\n", direction);
+                printf("STEP %i DETECTED\r\n", direction);
                 enqueue_packet(direction, current_time, packet_queue, 0);
                 other_countdown_triggered = false;
             }
@@ -223,12 +234,13 @@
         }
     } else {
         led = 1;
-        other_range_triggered = false;
+        this_range_triggered = false;
     }
 }
-
+ 
+// when connected to gateway, the HEAD and TAIL are added to the queue
 void connectionCallback(const Gap::ConnectionCallbackParams_t *) {
-    printf("Bluetooth connected at %i\n", current_time);
+    printf("Bluetooth connected at %i\r\n", current_time);
     ::master_connected = true;
     ::connection_triggered = false;
     enqueue_packet(-1, current_time, packet_queue, 1);
@@ -237,9 +249,11 @@
     wait(5);
 }
  
+// when disconnected from gateway, all variables reset to the initial state
+// as though system had restarted
 void disconnectionCallback(const Gap::DisconnectionCallbackParams_t *)
 {
-    printf("Bluetooth disconnected at %i\n", current_time);
+    printf("Bluetooth disconnected at %i\r\n", current_time);
     ::master_connected = false;
     ::timestamp = time_cycle;
     ::current_index = 0;
@@ -248,7 +262,8 @@
     ::triple_send_count = 0;
     BLE::Instance(BLE::DEFAULT_INSTANCE).gap().startAdvertising();
 }
- 
+
+// standard BLE init code found at https://os.mbed.com/teams/Bluetooth-Low-Energy/code/BLE_HeartRate/
 void bleInitComplete(BLE::InitializationCompleteCallbackContext *params)
 {
     BLE &ble          = params->ble;
@@ -272,6 +287,8 @@
     ble.gap().startAdvertising();
 }
  
+// called every 300ms to check whether a step has been taken and whether there
+// is anything to be transmitted
 void wakeup_event_cb() {
     ::timestamp++;
     ::current_time = timestamp / time_cycle;
@@ -305,6 +322,8 @@
                     range2_triggered, range1_triggered, packet_queue);
 }
  
+// system put to sleep by waitForEvent() call and periodically interrupted
+// by Ticker to check for steps and packets to send
 int main(void)
 {
     range1.init_sensor(range1_addr);