Jesse Kaiser / Mbed 2 deprecated EMG_HIDScope_Gr6

Highpass en Notch filter voor EMG verwerking

Dependencies:   HIDScope mbed-dsp mbed

Fork of EMG_HIDScope by First Last

main.cpp@15:d3a849ab3697, 2014-09-24 (annotated)

Committer:
vsluiter
Date:
Wed Sep 24 08:26:36 2014 +0000
Revision:
15:d3a849ab3697
Parent:
12:768048d7f742
Child:
16:24e992616cf6
added filter, not tested;

Who changed what in which revision?

UserRevisionLine numberNew contents of line
vsluiter 0:32bb76391d89 1 #include "mbed.h"
vsluiter 6:80c13d99aa55 2 #include "MODSERIAL.h"
vsluiter 0:32bb76391d89 3
vsluiter 4:8b298dfada81 4 //Define objects
vsluiter 7:3396c3e33928 5 AnalogIn emg0(PTB1); //Analog input
ArvidKeemink 1:db54d9412d18 6 PwmOut red(LED_RED); //PWM output
vsluiter 8:8a17f65622b4 7 Ticker log_timer;
vsluiter 8:8a17f65622b4 8 MODSERIAL pc(USBTX,USBRX);
vsluiter 2:e314bb3b2d99 9
vsluiter 15:d3a849ab3697 10 typedef struct second_order_constants
vsluiter 15:d3a849ab3697 11 {
vsluiter 15:d3a849ab3697 12 float b[3];
vsluiter 15:d3a849ab3697 13 float a[3];
vsluiter 15:d3a849ab3697 14 } second_order_constants_t;
vsluiter 15:d3a849ab3697 15
vsluiter 15:d3a849ab3697 16 typedef struct second_order_values
vsluiter 15:d3a849ab3697 17 {
vsluiter 15:d3a849ab3697 18 float x_1,x_2;
vsluiter 15:d3a849ab3697 19 float y_1,y_2;
vsluiter 15:d3a849ab3697 20 } second_order_values_t;
vsluiter 15:d3a849ab3697 21
vsluiter 15:d3a849ab3697 22 //constants
vsluiter 15:d3a849ab3697 23 second_order_constants_t highpass= {{0.97803048, -1.95606096, 0.97803048},{1, -1.95557824, 0.95654368}};
vsluiter 15:d3a849ab3697 24 //type for values
vsluiter 15:d3a849ab3697 25 second_order_values_t highpass_values;
vsluiter 15:d3a849ab3697 26
vsluiter 15:d3a849ab3697 27 float second_order(float x, second_order_constants_t constants, second_order_values_t &values);
vsluiter 15:d3a849ab3697 28
vsluiter 15:d3a849ab3697 29
vsluiter 4:8b298dfada81 30 /** Looper function
vsluiter 4:8b298dfada81 31 * functions used for Ticker and Timeout should be of type void <name>(void)
vsluiter 4:8b298dfada81 32 * i.e. no input arguments, no output arguments.
vsluiter 4:8b298dfada81 33 * if you want to change a variable that you use in other places (for example in main)
vsluiter 4:8b298dfada81 34 * you will have to make that variable global in order to be able to reach it both from
vsluiter 4:8b298dfada81 35 * the function called at interrupt time, and in the main function.
vsluiter 4:8b298dfada81 36 * To make a variable global, define it under the includes.
vsluiter 4:8b298dfada81 37 * variables that are changed in the interrupt routine (written to) should be made
vsluiter 4:8b298dfada81 38 * 'volatile' to let the compiler know that those values may change outside the current context.
vsluiter 8:8a17f65622b4 39 * i.e.: "volatile uint16_t emg_value;" instead of "uint16_t emg_value"
vsluiter 4:8b298dfada81 40 * in the example below, the variable is not re-used in the main function, and is thus declared
vsluiter 4:8b298dfada81 41 * local in the looper function only.
vsluiter 4:8b298dfada81 42 **/
vsluiter 2:e314bb3b2d99 43 void looper()
vsluiter 2:e314bb3b2d99 44 {
vsluiter 4:8b298dfada81 45 /*variable to store value in*/
vsluiter 8:8a17f65622b4 46 uint16_t emg_value;
vsluiter 15:d3a849ab3697 47 float filtered_emg;
vsluiter 4:8b298dfada81 48 /*put raw emg value both in red and in emg_value*/
vsluiter 10:09b8424a7b39 49 red.write(emg0.read()); // read float value (0..1 = 0..3.3V)
vsluiter 12:768048d7f742 50 emg_value = emg0.read_u16(); // read direct ADC result, converted to 16 bit integer (0..2^16 = 0..65536 = 0..3.3V)
vsluiter 15:d3a849ab3697 51 filtered_emg = second_order((float)emg_value,highpass, highpass_values);
vsluiter 8:8a17f65622b4 52 /*send value to PC. Line below is used to prevent buffer overrun */
vsluiter 6:80c13d99aa55 53 if(pc.rxBufferGetSize(0)-pc.rxBufferGetCount() > 30)
vsluiter 15:d3a849ab3697 54 pc.printf("%u\t%f\n",emg_value, filtered_emg);
vsluiter 5:4dacb7b72109 55 /**When not using the LED, the above could also have been done this way:
vsluiter 8:8a17f65622b4 56 * pc.printf("%u\n", emg0.read_u16());
vsluiter 5:4dacb7b72109 57 */
vsluiter 2:e314bb3b2d99 58 }
vsluiter 0:32bb76391d89 59
vsluiter 0:32bb76391d89 60 int main()
vsluiter 0:32bb76391d89 61 {
vsluiter 4:8b298dfada81 62 /*setup baudrate. Choose the same in your program on PC side*/
vsluiter 2:e314bb3b2d99 63 pc.baud(115200);
vsluiter 4:8b298dfada81 64 /*set the period for the PWM to the red LED*/
vsluiter 2:e314bb3b2d99 65 red.period_ms(2);
vsluiter 4:8b298dfada81 66 /**Here you attach the 'void looper(void)' function to the Ticker object
vsluiter 9:d33e7b175ad7 67 * The looper() function will be called every 0.01 seconds.
vsluiter 4:8b298dfada81 68 * Please mind that the parentheses after looper are omitted when using attach.
vsluiter 4:8b298dfada81 69 */
vsluiter 8:8a17f65622b4 70 log_timer.attach(looper, 0.01);
ArvidKeemink 1:db54d9412d18 71 while(1) //Loop
vsluiter 0:32bb76391d89 72 {
vsluiter 4:8b298dfada81 73 /*Empty!*/
vsluiter 4:8b298dfada81 74 /*Everything is handled by the interrupt routine now!*/
vsluiter 0:32bb76391d89 75 }
vsluiter 15:d3a849ab3697 76 }
vsluiter 15:d3a849ab3697 77
vsluiter 15:d3a849ab3697 78 float second_order(float x, second_order_constants_t constants, second_order_values_t &values)
vsluiter 15:d3a849ab3697 79 {
vsluiter 15:d3a849ab3697 80 float y = 0;
vsluiter 15:d3a849ab3697 81 float b_terms, a_terms;
vsluiter 15:d3a849ab3697 82 b_terms = (constants.b[0]*x) + (constants.b[1]*values.x_1) + (constants.b[2]*values.x_2);
vsluiter 15:d3a849ab3697 83 a_terms = (constants.a[1]*values.y_1) + (constants.a[2]*values.y_2);
vsluiter 15:d3a849ab3697 84 y=(1./constants.a[0])* (b_terms-a_terms);
vsluiter 15:d3a849ab3697 85 values.x_2 = values.x_1;
vsluiter 15:d3a849ab3697 86 values.x_1 = x;
vsluiter 15:d3a849ab3697 87 values.y_2 = values.y_1;
vsluiter 15:d3a849ab3697 88 values.y_1 = y;
vsluiter 15:d3a849ab3697 89 return y;
vsluiter 0:32bb76391d89 90 }