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@12:b9d71de8733d, 2015-12-08 (annotated)

Committer:
Krabby127
Date:
Tue Dec 08 02:10:55 2015 +0000
Revision:
12:b9d71de8733d
Parent:
11:791839389530
Child:
13:51e3bfd1f6c0
Updated for readability and equation corrections

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 12:b9d71de8733d 11 printf("\n\rAnalogIn example\n\r");
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 12:b9d71de8733d 14 meas = meas * 3.3; // Change the value to be in the 0 to 3.3 range (currently to mV)
Krabby127 12:b9d71de8733d 15 printf("meas = %fmV\n\r",meas*1000); // Print out raw measurement in terms of mV
Krabby127 12:b9d71de8733d 16 b=(meas-(3.3/2.0))/(4.0*12.2*100.0); // Based on equation 1 from DRV425EVM pdf
Krabby127 12:b9d71de8733d 17 //VVOUT [V] = B × G × RSHUNT × GAMP = B [uT] × 12.2 mA/mT × RSHUNT [Ω] × 4 [V/V]
Krabby127 11:791839389530 18 //VVOUT is with reference to REFIN
Krabby127 12:b9d71de8733d 19 // 0 Tesla is VDD/2
Krabby127 3:7285d6ff672b 20 // 12.2 mA/mT
Krabby127 12:b9d71de8733d 21 printf("b = %fuT\n\r",b); // Print out b field measure in micro-Tesla
Krabby127 12:b9d71de8733d 22 printf("b = %fuT\n\r", b/100.0); // Output B field in Gauss
Krabby127 12:b9d71de8733d 23 if (meas > 1.65) { // If the value is greater than 1.65V then switch the LED on
Krabby127 12:b9d71de8733d 24 // positive magnetic field
Krabby127 0:cbee968c2ec3 25 led = 1;
Krabby127 0:cbee968c2ec3 26 }
Krabby127 0:cbee968c2ec3 27 else {
Krabby127 0:cbee968c2ec3 28 led = 0;
Krabby127 0:cbee968c2ec3 29 }
davidcerrone 9:4b887a45ac8c 30 wait(1); // wait 1 second
Krabby127 0:cbee968c2ec3 31 }
Krabby127 0:cbee968c2ec3 32 }