Marco Virgolin / Mbed 2 deprecated ProgEmbedded_Joystick

Program that reads data from the FRDM-KL25Z capacitive slider and accellerometer and sends it to the serial port in JSON format.

Dependencies:   MMA8451Q TSI mbed

Fork of FRDM_TSI by Subhrajit Mitra

This code is part of a project for the course in Computer Engineering "Progettazione di Applicazioni per Dispositivi Embedded (Designing of Applications for Embedded Devices)" , held by professor Omero Tuzzi, at the University of Trieste.

The code reads data from the board sensors (capacitive touch slider and accelerometer) and makes the RGB led assume a color according to the readings. It also sends a JSON-format message about the readings to the USB Serial Port.

Files at this revision

API Documentation at this revision

Revision 7:ebf728afc308, committed 2014-09-21

Comitter:
remarkus89
Date:
Sun Sep 21 16:48:20 2014 +0000
Parent:
6:38459146ad89
Commit message:
Added comments to explain the code.

Changed in this revision

main.cpp Show annotated file Show diff for this revision Revisions of this file 
--- a/main.cpp	Sun Sep 21 16:18:16 2014 +0000
+++ b/main.cpp	Sun Sep 21 16:48:20 2014 +0000
@@ -1,30 +1,46 @@
+// Inclusion of necessary libraries
 #include "mbed.h"
 #include "TSISensor.h"
 #include "MMA8451Q.h"
 #include "stdio.h"
 
+// Declaration of constants
 #define MMA8451_I2C_ADDRESS (0x1d<<1)
 #define ACC_THRESH 0.1
 #define WAIT_TIME 0.01
 
 int main(void) {
+    // Declare accelerometer
     MMA8451Q acc(PTE25, PTE24, MMA8451_I2C_ADDRESS);
     
+    // Declare components of the RGB led
     PwmOut led_blue(LED_BLUE);
     PwmOut led_green(LED_GREEN);
     PwmOut led_red(LED_RED);
     
+    // Declare capacitive touch slider
     float tp=0;
     TSISensor tsi;
+    
+    // Declare USB Serial Port
     Serial pc(USBTX, USBRX);
-   
+    
+    // Turn off all the components of the RGB led
     led_blue = 1;
     led_green = 1;
     led_red = 1;
     
     while (1) 
     {   
+        // Read the slider and assign the readed value to the tp variable. 
+        // tp assumes a value between 0 (user is not touching the slider) 
+        // and 1 (user is touching the upper part of the slider). 
         tp = tsi.readPercentage();
+        
+        // If the user is NOT touching the slider, then make RGB led assume
+        // a color accourding to the declivity measured by the accelerometer.
+        // Green intensity is used to represent the vertical axe (y), 
+        // Blue intensity is used to represent the horizontal one (x).
         if (tp == 0){
             led_red = 1;
             if (abs(acc.getAccX()) >= ACC_THRESH)
@@ -35,16 +51,22 @@
                 led_green = 1-abs(acc.getAccY());
             else 
                 led_green = 1;
+        // If the user is touching the upper part of the slider, make the RGB led
+        // assume the Red color
         } else if (tp >= 0.5) {
             led_blue = 1;
             led_green = 1;
             led_red = 0;
+        // If the user is touching the lower part of the slider, make the RGB led
+        // assume the White color
         } else {
             led_blue = 0;
             led_green = 0;
             led_red = 0;
         }
+        // Send a JSON-format message of the measurements to the Serial Port
         pc.printf("{ \"slider\" : %f, \"acc_x\" : %f, \"acc_y\" : %f, \"acc_z\" : %f }\n", tp, acc.getAccX(), acc.getAccY(), acc.getAccZ());
+        // Wait a fixed amount of time before repeating the whole while-cycle
         wait(WAIT_TIME);
     }
 }
\ No newline at end of file