main.cpp

00001 #include "mbed.h"
00002 #include "ble/BLE.h"
00003 
00004 #define THRESHOLD_PRESS 0.08
00005 #define TIME_BETWEEN_TOUCH 0.05
00006 #define TIME_BETWEEN_CYCLE 0.1
00007 
00008 #define LEFT_PUSH 1
00009 #define RIGHT_PUSH 2
00010 #define LEFT_SWIPE 3
00011 #define RIGHT_SWIPE 4
00012 
00013 /* Four capacitive touch inputs; active low
00014  * Two on the left, two on the right, all in one row */
00015 DigitalIn touch1(P0_12);
00016 DigitalIn touch2(P0_13);
00017 DigitalIn touch3(P0_14);
00018 DigitalIn touch4(P0_15);
00019 
00020 /* One pressure sensor input */
00021 AnalogIn press(P0_1);
00022 
00023 /* One haptic input */
00024 /* PwmOut  haptic(P0_16); */
00025 
00026 /* Choose custom GATT UUIDS and profile name */
00027 uint16_t customServiceUUID  = 0xA000;
00028 uint16_t readCharUUID       = 0xA001;
00029 const static char     DEVICE_NAME[] = "Touch Signal";
00030 static const uint16_t uuid16_list[] = {0xA000}; /* Custom UUID, FFFF is reserved for development */
00031 
00032 /* Variable used to search for inputs every 0.3 seconds and prevent connection timeout */
00033 static volatile bool triggerSensorPolling = false;
00034 
00035 /* Ouput variable */
00036 uint8_t readSignal = 0;
00037 
00038 /* Set up custom read characteristic*/
00039 ReadOnlyGattCharacteristic<uint8_t> readChar(readCharUUID, &readSignal, GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY);
00040 
00041 /* Set up custom service */
00042 GattCharacteristic *characteristics[] = {&readChar};
00043 GattService        customService(customServiceUUID, characteristics, sizeof(characteristics) / sizeof(GattCharacteristic *));
00044 
00045 /* Restart advertising when phone app disconnects */
00046 void disconnectionCallback(const Gap::DisconnectionCallbackParams_t *){
00047     BLE::Instance(BLE::DEFAULT_INSTANCE).gap().startAdvertising();
00048 }
00049 
00050 void periodicCallback(void){
00051     /* Note that the periodicCallback() executes in interrupt context, so it is safer to do
00052      * heavy-weight sensor polling from the main thread. */
00053     triggerSensorPolling = true;
00054 }
00055 
00056 /* Initialization callback */
00057 void bleInitComplete(BLE::InitializationCompleteCallbackContext *params){
00058     BLE &ble          = params->ble;
00059     ble_error_t error = params->error;
00060     if(error != BLE_ERROR_NONE){
00061         return;
00062     }
00063     ble.gap().onDisconnection(disconnectionCallback);
00064     /* Setup advertising */
00065     ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::BREDR_NOT_SUPPORTED | GapAdvertisingData::LE_GENERAL_DISCOVERABLE); /* BLE only, no classic BT */
00066     ble.gap().setAdvertisingType(GapAdvertisingParams::ADV_CONNECTABLE_UNDIRECTED); /* Advertising type */
00067     ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LOCAL_NAME, (uint8_t *)DEVICE_NAME, sizeof(DEVICE_NAME)); /* Add name */
00068     ble.gap().accumulateAdvertisingPayload(GapAdvertisingData::COMPLETE_LIST_16BIT_SERVICE_IDS, (uint8_t *)uuid16_list, sizeof(uuid16_list)); /* UUID's broadcast in advertising packet */
00069     ble.gap().setAdvertisingInterval(300); /* 300 ms */
00070     /* Add custom service */
00071     ble.addService(customService);
00072     /* Start advertising */
00073     ble.gap().startAdvertising();
00074 }
00075 
00076 void pressed(){
00077     /* Check which side of capacitive touch pad is being touched */
00078     if((touch1 == 0 || touch2 == 0) && (touch3 == 1 && touch4 == 1)){
00079         /* Left push
00080          * Success buzz */
00081         readSignal = LEFT_PUSH;
00082     }
00083     else if((touch3 == 0 || touch4 == 0) && (touch1 == 1 && touch2 == 1)){
00084         /* Right push
00085          * Success buzz */
00086         readSignal = RIGHT_PUSH;
00087     }
00088     /* If both sides are pressed, there is an error */
00089     else{
00090         /* Failure buzz */
00091         wait(TIME_BETWEEN_CYCLE);
00092     }
00093 }
00094 
00095 /* Three out of four of the switches need to be touched in the correct order */
00096 void swiped_right(){
00097     /* Assign bool variable that turns true if no error: if true, then there is a swipe */
00098     bool checkSwipe = false;
00099     /* Variables used for polling */
00100     int i, j;
00101     /* If the leftmost switch is touched, check if the next one is touched */
00102     if(touch1 == 0){
00103         /* If both left switches are touched, only one of the right switches need to be touched */
00104         if(touch2 == 0){
00105             /* Variables i and j are used for polling in a while loop 5 times to search for a touch
00106              * If the required input is sensed it exits the while loop to sense the next input or make checkSwipe true
00107              * Every time there is no input i or j increments
00108              * If no input is sensed and i = 5 or j = 5, then it exits the while loop to keep checkSwipe false */
00109             i = 5;
00110             while(i > 0){
00111                 wait(TIME_BETWEEN_TOUCH);
00112                 /* If one of the right switches are touched next, then checkSwipe is true */
00113                 if(touch3 == 0 || touch4 == 0){
00114                     checkSwipe = true;
00115                     i = 0;
00116                 }
00117                 else{
00118                     i--;
00119                 }
00120             }
00121         }
00122         else{
00123             i = 5;
00124             while(i > 0){
00125                 wait(TIME_BETWEEN_TOUCH);
00126                 /* If only the leftmost switch is touched, check if the other left switch is touched */
00127                 if(touch2 == 0){
00128                     j = 5;
00129                     while(j > 0){
00130                         wait(TIME_BETWEEN_TOUCH);
00131                         /* If both left switches are touched, only one of the right switches need to be touched for checkSwipe to be true */
00132                         if(touch3 == 0 || touch4 == 0){
00133                             checkSwipe = true;
00134                             j = 0;
00135                         }
00136                         else{
00137                             j--;
00138                         }
00139                     }
00140                     i = 0;
00141                 }
00142                 /* If the leftmost switch is touched and the third switch after, only the rightmost switch needs to be touched */
00143                 else if(touch3 == 0){
00144                     j = 5;
00145                     while(j > 0){
00146                         wait(TIME_BETWEEN_TOUCH);
00147                         /* If the rightmost switch is touched, checkSwipe becomes true */
00148                         if(touch4 == 0){
00149                             checkSwipe = true;
00150                             j = 0;
00151                         }                                  
00152                         else{
00153                             j--;
00154                         }
00155                     }
00156                 }          
00157                 else{
00158                     i--;
00159                 }
00160             }
00161         }
00162     }
00163     /* If only the second switchs is touched, the two right switches need to be touched */
00164     else{
00165         i = 5;
00166         while(i > 0){
00167             wait(TIME_BETWEEN_TOUCH);
00168             /* If the third switch is touched, check if the rightmost switch is touched */
00169             if(touch3 == 0){
00170                 j = 5;
00171                 while(j > 5){
00172                     wait(TIME_BETWEEN_TOUCH);
00173                     /* If the rightmost switch is touched, checkSwipe becomes true */
00174                     if(touch4 == 0){
00175                         checkSwipe = true;
00176                         j = 0;
00177                     }                    
00178                     else{
00179                         j--;
00180                     }
00181                 }
00182                 i = 0;
00183             }  
00184             else{
00185                 i--;
00186             }
00187         }
00188     }
00189     /* If checkSwipe is true, then there was a swipe gesture */
00190     if(checkSwipe){
00191         /* Right swipe
00192          * Success buzz */
00193         readSignal = RIGHT_SWIPE;
00194     }
00195     /* If checkswipe is false, then there was an error */
00196     else{
00197         /* Failure buzz */
00198         wait(TIME_BETWEEN_CYCLE);
00199     }
00200 }
00201 
00202 /* Three out of four of the switches need to be touched in the correct order
00203  * Same as swiped_right except in opposite direction */
00204 void swiped_left(){
00205     bool checkSwipe = false;
00206     int i, j;
00207     if(touch4 == 0){
00208         if(touch3 == 0){
00209             i = 5;
00210             while(i > 0){
00211                 wait(TIME_BETWEEN_TOUCH);
00212                 if(touch2 == 0 || touch1 == 0){
00213                     checkSwipe = true;
00214                     i = 0;
00215                 }
00216                 else{
00217                     i--;
00218                 }
00219             }
00220         }
00221         else{
00222             i = 5;
00223             while(i > 0){
00224                 wait(TIME_BETWEEN_TOUCH);
00225                 if(touch3 == 0){
00226                     j = 5;
00227                     while(j > 0){
00228                         wait(TIME_BETWEEN_TOUCH);
00229                         if(touch2 == 0 || touch1 == 0){
00230                             checkSwipe = true;
00231                             j = 0;
00232                         }
00233                         else{
00234                             j--;
00235                         }
00236                     }
00237                     i = 0;
00238                 }
00239                 else if(touch2 == 0){
00240                     j = 5;
00241                     while(j > 0){
00242                         wait(TIME_BETWEEN_TOUCH);
00243                         if(touch1 == 0){
00244                             checkSwipe = true;
00245                             j = 0;
00246                         }
00247                         else{
00248                             j--;
00249                         }
00250                     }
00251                 }
00252                 else{
00253                     i--;
00254                 }
00255             }
00256         }
00257     }
00258     else{
00259         i = 5;
00260         while(i > 0){
00261             wait(TIME_BETWEEN_TOUCH);
00262             if(touch2 == 0){
00263                 j = 5;
00264                 while(j > 5){
00265                     wait(TIME_BETWEEN_TOUCH);
00266                     if(touch1 == 0){
00267                         checkSwipe = true;
00268                         j = 0;
00269                     }
00270                     else{
00271                         j--;
00272                     }
00273                 }
00274                 i = 0;
00275             }
00276             else{
00277                 i--;
00278             }
00279         }
00280     }
00281     if(checkSwipe){
00282         /* Left swipe
00283          * Success buzz */
00284         readSignal = LEFT_SWIPE;
00285     }
00286     else{
00287         /* Failure buzz */
00288         wait(TIME_BETWEEN_CYCLE);
00289     }
00290 }
00291 
00292 /* Main loop */
00293 int main(){
00294     
00295     /* Setup of recurring interrupt to look for inputs every 0.3 seconds */
00296     Ticker ticker;
00297     ticker.attach(periodicCallback, 0.3);
00298     
00299     /* Initialise BLE */
00300     BLE& ble = BLE::Instance(BLE::DEFAULT_INSTANCE);
00301     ble.init(bleInitComplete);
00302     
00303     /* SpinWait for initialization to complete. This is necessary because the
00304      * BLE object is used in the main loop below. */
00305     while(ble.hasInitialized() == false){/* Spin loop */}
00306 
00307     /* Infinite loop waiting for BLE interrupt events */
00308     while(1){
00309         /* Check for trigger from periodicCallback() */
00310         if(triggerSensorPolling && ble.getGapState().connected){
00311             triggerSensorPolling = false;
00312             /* Check if touch pad is pressed beyond threshold for pressing gesture */
00313             if(press > THRESHOLD_PRESS){
00314                 pressed();
00315             }
00316             /* Check if touch pad is touched on one side for swiping gesture
00317              * A touch on the left side would potentially be a right swipe */
00318             else if((touch1 == 0 || touch2 == 0) && (touch3 == 1 && touch4 == 1)){
00319                 swiped_right();
00320             }
00321             /* A touch on the right side would potentially be a left swipe */
00322             else if((touch4 == 0 || touch3 == 0) && (touch2 == 1 && touch1 == 1)){
00323                 swiped_left();
00324             }
00325             /* Input is not sent via Bluetooth if 0
00326              * If not 0, send and reset to 0 for next input cycle */
00327             if(readSignal != 0){
00328                 ble.updateCharacteristicValue(readChar.getValueHandle(), &readSignal, 1);
00329                 readSignal = 0;
00330                 wait(TIME_BETWEEN_CYCLE);
00331             }
00332         }
00333         else{
00334             ble.waitForEvent(); /* Low power wait for event */
00335         }
00336     }
00337 }