Revision 14:8ceaa97cc85c, committed 2020-12-01

Comitter:

bky

Date:

Tue Dec 01 09:08:37 2020 +0000

Parent:

13:a1a9f2282f15

Child:

15:e073df8f635b

Commit message:

created header file for 7 segment display driver

Changed in this revision

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/displayDriver.h	Tue Dec 01 09:08:37 2020 +0000
@@ -0,0 +1,5 @@
+# ifndef DISPLAY_DRIVER_H
+# define DISPLAY_DRIVER_H
+void display(float);
+
+# endif

--- a/main.cpp	Tue Dec 01 05:17:25 2020 +0000
+++ b/main.cpp	Tue Dec 01 09:08:37 2020 +0000
@@ -1,81 +1,53 @@
 # include "mbed.h"
 # include "Timer.h"
 
-# include <stdlib.h>
 # include <time.h>
-# include <limits>
-# include <queue>
-
 # define NUM_HOLES 32
 # define CIRCUMFRENCE_CM 48.6946861
 
 # define LIGHT_SENSOR_PIN p15
-# define FLASH_THRESHOLD 0.97
+# define FLASH_THRESHOLD 0.02
+# define PERIOD_MS 500
 
 
 AnalogIn lightSensorVoltage(LIGHT_SENSOR_PIN);
 Serial pc(USBTX, USBRX);
 
-DigitalOut myled(LED1);
-
-int lastFlash = 0;
-float prevVoltReading = 0.0;
-float currVoltReading = 0.0;
-float miliPerRotation = std::numeric_limits<float>::max();
-
-//float getAverage(queue<float> q) {
-//printf("g");
-//    float sum = 0;
-//    while(!q.empty()) {
-//printf("h");
-//        sum += q.front();
-//        q.pop();
-//    }
-//    
-//    return sum / q.size();
-//}
-
 void sendFloat(float value) {
     for (int i=0; i<4; i++)
         pc.putc(*(((char*) &value)+i));
 }
 
-int main() {
-    Timer timer;
-    timer.start();
-    int currTime = 0;
-    int prevTime = 0;
+void displayThread() {
     
-    float currVelocity = 0;
-    float prevVelocity = 0;
-    
-    sendFloat(0);
-    while(1) {
-        currVoltReading = lightSensorVoltage.read();
+}
+
+int main() {
+    while(true) {
+        float minVoltage = 1.1; // voltage will never go above 1.0
+        int voltagePeaks = 0;
         
-        prevVelocity = currVelocity;
+        Timer t;
+        t.start();
         
-//printf("volt %f\n", currVoltReading);
-        if(currVoltReading - prevVoltReading > 0.02) {
-            currTime = timer.read_ms();
-//printf("currTime %i\n", currTime);
-//printf("prevTime %i\n", prevTime);
-            miliPerRotation = (currTime - prevTime) * NUM_HOLES;
-//printf("time diff %i\n", currTime - prevTime);
-//printf("MPRs %f\n", miliPerRotation);
-            
-            prevTime = currTime;
-            currVelocity = CIRCUMFRENCE_CM * 1000 / miliPerRotation;
+        while(t.read_ms() < PERIOD_MS) {
+            float currVoltage = lightSensorVoltage.read();
+            if(currVoltage < minVoltage) {
+                minVoltage = currVoltage;
+            } else if (currVoltage - minVoltage > FLASH_THRESHOLD) {
+                voltagePeaks++;
+                minVoltage = 1.1;
+            }
+            wait(0.01);
         }
         
-        if(currVelocity != 0 && currVelocity == prevVelocity) {
-            currVelocity = 0;    
-        }
+        t.stop();
         
-        sendFloat(currVelocity);
+        // calculate velocity
+        float velocity = (voltagePeaks * CIRCUMFRENCE_CM * 1000) / (NUM_HOLES * PERIOD_MS);
         
-//printf("velocity %f\n", velocity);
-        prevVoltReading = currVoltReading;
-        wait(0.05);
+        //send 
+        sendFloat(velocity);
     }
+    return 0;    
 }
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