OhmBoyZ_Capstone / Mbed 2 deprecated MagneticRead Featured

This is the development sandbox for the DRV425EVM and its magnetic sensing.

Dependencies:   mbed

/media/uploads/Krabby127/ohmboyzvectorized.png

Repository for the 2015 OhmBoyZ Capstone group.

main.cpp@5:760f85b3f309, 2015-11-25 (annotated)

Committer:
Krabby127
Date:
Wed Nov 25 02:28:53 2015 +0000
Revision:
5:760f85b3f309
Parent:
4:769396add1a8
Child:
6:2f0942f33585
Child:
7:405e3ff6cbcd
Corrected equation to measure around 0 Tesla

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Krabby127 0:cbee968c2ec3 1 #include "mbed.h"
Krabby127 0:cbee968c2ec3 2 #include <math.h>
Krabby127 0:cbee968c2ec3 3
Krabby127 0:cbee968c2ec3 4 AnalogIn analog_value(A0);
Krabby127 0:cbee968c2ec3 5
Krabby127 0:cbee968c2ec3 6 DigitalOut led(LED1);
Krabby127 0:cbee968c2ec3 7
Krabby127 0:cbee968c2ec3 8 int main() {
Krabby127 0:cbee968c2ec3 9 float meas;
Krabby127 0:cbee968c2ec3 10 float b;
Krabby127 0:cbee968c2ec3 11 printf("\nAnalogIn example\n");
Krabby127 0:cbee968c2ec3 12 while(1) {
Krabby127 0:cbee968c2ec3 13 meas = analog_value.read(); // Converts and read the analog input value (value from 0.0 to 1.0)
Krabby127 0:cbee968c2ec3 14 meas = meas * 3300; // Change the value to be in the 0 to 3300 range (currently to mV)
Krabby127 1:d901038c4bd2 15 printf("meas = %fmV\n\r",meas); // Print out raw measurement in terms of mV
Krabby127 5:760f85b3f309 16 b=((meas/1000)/(4.0*12.2*100.0))-3.3/2.0; // Based on equation 1
Krabby127 5:760f85b3f309 17 //VVOUT [V] = B × G × RSHUNT × GAMP = B [mT] × 12.2 mA/mT × RSHUNT [Ω] × 4 [V/V]
Krabby127 5:760f85b3f309 18 //0 Tesla is VDD/2
Krabby127 3:7285d6ff672b 19 // 12.2 mA/mT
Krabby127 5:760f85b3f309 20 printf("b = %f Gauss\n\r",b); // Print out b field measure in milliTesla
Krabby127 5:760f85b3f309 21 printf("B = %fuT\n\r", b*1000.0); // Output B field in micro-Tesla
Krabby127 1:d901038c4bd2 22 if (meas > 2000) { // If the value is greater than 2V then switch the LED on
Krabby127 1:d901038c4bd2 23 // greater than 410 microGauss [40 mT]
Krabby127 0:cbee968c2ec3 24 led = 1;
Krabby127 0:cbee968c2ec3 25 }
Krabby127 0:cbee968c2ec3 26 else {
Krabby127 0:cbee968c2ec3 27 led = 0;
Krabby127 0:cbee968c2ec3 28 }
Krabby127 3:7285d6ff672b 29 wait(.1); // wait 1 second
Krabby127 0:cbee968c2ec3 30 }
Krabby127 0:cbee968c2ec3 31 }