A Clark
/
RF_ID
Log Test Code
Fork of VoltageThreshold by
Diff: main.cpp
- Revision:
- 3:9b47638100af
- Parent:
- 2:d5b23f4e6884
--- a/main.cpp Wed Apr 02 12:26:31 2014 +0000 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,43 +0,0 @@ -#include "mbed.h" -#define PI 3.1415 - -Timer t; - -AnalogIn ain_v1(p20); // Input voltage from antenna - - -int main() -{ - float v1, m, b, p_in, Pt, Gt, Gr, Pr, f, c, r; - - t.start(); - while(t.read()<10.0) - { - // Voltage to Power calculations - v1 = ain_v1; // ain_v1; // Comes from mBed (Can adjust manually for now) - b = 2.095; // (volts) Direct function generator measurement - m = .0316; // volts/dBm (Calculated at 2000 MHz and 0 and -40 dBm) - p_in = (v1-b)/m; // Derived from v = m*p+b (linear relationship of voltage and power) - - // Range equation Terms - Pt = .001; //(watts or 1mW or 0 dBm) Power Transmitted. This is ~16 dBm (.0398 watts) for an iphone 5 - Gt = 1; // Unitless (1 for FG) Shouldn't both of these gains be 'directive' gains, not power gains - Gr = .007; // (.007) (7 mW) How do we get this? Should be on datasheet... but calc required? 7 milliwatt? - Pr = pow(10, ((p_in-30)/10)); // (watts) - - // Free Space Loss Terms - f = 2000000000; // (Hz) This will be constant for a phone... but what to put for the FG - c = 300000000; // m/s - - r = (c*(sqrt(Pt*Gt*Gr)/Pr))/(4*PI*f); - - //printf("\rRange (meters) = %.3f\n\r",r); - //printf("Power (watts) = %.4f\n\r",Pr); - printf("Voltage into mBed = %.4f\n\r",v1); - } -} - - - - -