First Last / Mbed 2 deprecated EMG_HIDScope

Measure EMG, publish on HID Scope

Dependencies:   HIDScope mbed mbed-dsp

Fork of EMG by First Last

main.cpp@18:fed07cc1f8f6, 2014-09-29 (annotated)

Committer:
vsluiter
Date:
Mon Sep 29 11:42:37 2014 +0000
Revision:
18:fed07cc1f8f6
Parent:
17:1388f1a2d7b2
Child:
19:dbc1bca498e3
Using arm_math functions for IIR filters;

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 11:ce72ec658a95 3 #include "HIDScope.h"
vsluiter 0:32bb76391d89 4
vsluiter 18:fed07cc1f8f6 5 #include "arm_math.h"
vsluiter 18:fed07cc1f8f6 6
vsluiter 4:8b298dfada81 7 //Define objects
vsluiter 7:3396c3e33928 8 AnalogIn emg0(PTB1); //Analog input
ArvidKeemink 1:db54d9412d18 9 PwmOut red(LED_RED); //PWM output
vsluiter 8:8a17f65622b4 10 Ticker log_timer;
vsluiter 8:8a17f65622b4 11 MODSERIAL pc(USBTX,USBRX);
vsluiter 11:ce72ec658a95 12 HIDScope scope(2);
vsluiter 2:e314bb3b2d99 13
vsluiter 18:fed07cc1f8f6 14 arm_biquad_casd_df1_inst_f32 lowpass;
vsluiter 18:fed07cc1f8f6 15 float lowpass_const[] = {0.02008337 , 0.04016673 , 0.02008337 , 1.56101808 , -0.64135154};
vsluiter 18:fed07cc1f8f6 16 float lowpass_states[4];
vsluiter 18:fed07cc1f8f6 17
vsluiter 18:fed07cc1f8f6 18 arm_biquad_casd_df1_inst_f32 highpass;
vsluiter 18:fed07cc1f8f6 19 float highpass_const[] = {0.97803048, -1.95606096, 0.97803048, 1.95557824 , -0.95654368};
vsluiter 18:fed07cc1f8f6 20 volatile float highpass_states[4];
vsluiter 18:fed07cc1f8f6 21
vsluiter 18:fed07cc1f8f6 22 /*
vsluiter 15:d3a849ab3697 23 typedef struct second_order_constants
vsluiter 15:d3a849ab3697 24 {
vsluiter 15:d3a849ab3697 25 float b[3];
vsluiter 15:d3a849ab3697 26 float a[3];
vsluiter 15:d3a849ab3697 27 } second_order_constants_t;
vsluiter 15:d3a849ab3697 28
vsluiter 15:d3a849ab3697 29 typedef struct second_order_values
vsluiter 15:d3a849ab3697 30 {
vsluiter 15:d3a849ab3697 31 float x_1,x_2;
vsluiter 15:d3a849ab3697 32 float y_1,y_2;
vsluiter 15:d3a849ab3697 33 } second_order_values_t;
vsluiter 15:d3a849ab3697 34
vsluiter 15:d3a849ab3697 35 //constants
vsluiter 15:d3a849ab3697 36 second_order_constants_t highpass= {{0.97803048, -1.95606096, 0.97803048},{1, -1.95557824, 0.95654368}};
vsluiter 17:1388f1a2d7b2 37 second_order_constants_t lowpass={{ 0.02008337 , 0.04016673 , 0.02008337},{1.0, -1.56101808, 0.64135154}};
vsluiter 15:d3a849ab3697 38 //type for values
vsluiter 17:1388f1a2d7b2 39 second_order_values_t highpass_values, lowpass_values;
vsluiter 15:d3a849ab3697 40
vsluiter 18:fed07cc1f8f6 41
vsluiter 18:fed07cc1f8f6 42 //function definition
vsluiter 15:d3a849ab3697 43 float second_order(float x, second_order_constants_t constants, second_order_values_t &values);
vsluiter 18:fed07cc1f8f6 44 */
vsluiter 15:d3a849ab3697 45
vsluiter 4:8b298dfada81 46 /** Looper function
vsluiter 4:8b298dfada81 47 * functions used for Ticker and Timeout should be of type void <name>(void)
vsluiter 4:8b298dfada81 48 * i.e. no input arguments, no output arguments.
vsluiter 4:8b298dfada81 49 * if you want to change a variable that you use in other places (for example in main)
vsluiter 4:8b298dfada81 50 * you will have to make that variable global in order to be able to reach it both from
vsluiter 4:8b298dfada81 51 * the function called at interrupt time, and in the main function.
vsluiter 4:8b298dfada81 52 * To make a variable global, define it under the includes.
vsluiter 4:8b298dfada81 53 * variables that are changed in the interrupt routine (written to) should be made
vsluiter 4:8b298dfada81 54 * 'volatile' to let the compiler know that those values may change outside the current context.
vsluiter 8:8a17f65622b4 55 * i.e.: "volatile uint16_t emg_value;" instead of "uint16_t emg_value"
vsluiter 4:8b298dfada81 56 * in the example below, the variable is not re-used in the main function, and is thus declared
vsluiter 4:8b298dfada81 57 * local in the looper function only.
vsluiter 4:8b298dfada81 58 **/
vsluiter 2:e314bb3b2d99 59 void looper()
vsluiter 2:e314bb3b2d99 60 {
vsluiter 4:8b298dfada81 61 /*variable to store value in*/
vsluiter 8:8a17f65622b4 62 uint16_t emg_value;
vsluiter 15:d3a849ab3697 63 float filtered_emg;
vsluiter 18:fed07cc1f8f6 64 float emg_value_f32;
vsluiter 4:8b298dfada81 65 /*put raw emg value both in red and in emg_value*/
vsluiter 10:09b8424a7b39 66 red.write(emg0.read()); // read float value (0..1 = 0..3.3V)
vsluiter 12:768048d7f742 67 emg_value = emg0.read_u16(); // read direct ADC result, converted to 16 bit integer (0..2^16 = 0..65536 = 0..3.3V)
vsluiter 18:fed07cc1f8f6 68 emg_value_f32 = emg0.read();
vsluiter 18:fed07cc1f8f6 69 //filtered_emg = second_order((float)emg_value,highpass, highpass_values);
vsluiter 18:fed07cc1f8f6 70 arm_biquad_cascade_df1_f32(&highpass, &emg_value_f32, &filtered_emg, 1 );
vsluiter 18:fed07cc1f8f6 71 filtered_emg = fabs(filtered_emg);
vsluiter 18:fed07cc1f8f6 72 arm_biquad_cascade_df1_f32(&lowpass, &filtered_emg, &filtered_emg, 1 );
vsluiter 8:8a17f65622b4 73 /*send value to PC. Line below is used to prevent buffer overrun */
vsluiter 11:ce72ec658a95 74 scope.set(0,emg_value);
vsluiter 18:fed07cc1f8f6 75 //scope.set(1,second_order(fabs(filtered_emg), lowpass, lowpass_values));
vsluiter 18:fed07cc1f8f6 76 scope.set(1,filtered_emg);
vsluiter 11:ce72ec658a95 77 scope.send();
vsluiter 16:24e992616cf6 78
vsluiter 5:4dacb7b72109 79 /**When not using the LED, the above could also have been done this way:
vsluiter 8:8a17f65622b4 80 * pc.printf("%u\n", emg0.read_u16());
vsluiter 5:4dacb7b72109 81 */
vsluiter 2:e314bb3b2d99 82 }
vsluiter 0:32bb76391d89 83
vsluiter 0:32bb76391d89 84 int main()
vsluiter 0:32bb76391d89 85 {
vsluiter 4:8b298dfada81 86 /*setup baudrate. Choose the same in your program on PC side*/
vsluiter 14:94a4a5863689 87 //pc.baud(115200);
vsluiter 4:8b298dfada81 88 /*set the period for the PWM to the red LED*/
vsluiter 2:e314bb3b2d99 89 red.period_ms(2);
vsluiter 4:8b298dfada81 90 /**Here you attach the 'void looper(void)' function to the Ticker object
vsluiter 9:d33e7b175ad7 91 * The looper() function will be called every 0.01 seconds.
vsluiter 4:8b298dfada81 92 * Please mind that the parentheses after looper are omitted when using attach.
vsluiter 4:8b298dfada81 93 */
vsluiter 18:fed07cc1f8f6 94 //set up filters
vsluiter 18:fed07cc1f8f6 95 arm_biquad_cascade_df1_init_f32(&lowpass,1 , lowpass_const, lowpass_states);
vsluiter 18:fed07cc1f8f6 96 arm_biquad_cascade_df1_init_f32(&highpass,1 ,highpass_const, (float *)highpass_states);
vsluiter 13:18d4cef1fdb4 97 log_timer.attach(looper, 0.005);
ArvidKeemink 1:db54d9412d18 98 while(1) //Loop
vsluiter 0:32bb76391d89 99 {
vsluiter 4:8b298dfada81 100 /*Empty!*/
vsluiter 4:8b298dfada81 101 /*Everything is handled by the interrupt routine now!*/
vsluiter 0:32bb76391d89 102 }
vsluiter 15:d3a849ab3697 103 }
vsluiter 15:d3a849ab3697 104
vsluiter 18:fed07cc1f8f6 105
vsluiter 18:fed07cc1f8f6 106 /*
vsluiter 15:d3a849ab3697 107 float second_order(float x, second_order_constants_t constants, second_order_values_t &values)
vsluiter 15:d3a849ab3697 108 {
vsluiter 15:d3a849ab3697 109 float y = 0;
vsluiter 15:d3a849ab3697 110 float b_terms, a_terms;
vsluiter 15:d3a849ab3697 111 b_terms = (constants.b[0]*x) + (constants.b[1]*values.x_1) + (constants.b[2]*values.x_2);
vsluiter 15:d3a849ab3697 112 a_terms = (constants.a[1]*values.y_1) + (constants.a[2]*values.y_2);
vsluiter 15:d3a849ab3697 113 y=(1./constants.a[0])* (b_terms-a_terms);
vsluiter 15:d3a849ab3697 114 values.x_2 = values.x_1;
vsluiter 15:d3a849ab3697 115 values.x_1 = x;
vsluiter 15:d3a849ab3697 116 values.y_2 = values.y_1;
vsluiter 15:d3a849ab3697 117 values.y_1 = y;
vsluiter 15:d3a849ab3697 118 return y;
vsluiter 18:fed07cc1f8f6 119 }*/