EcgSmartApp - A Low Cost ECG Device

1int value=0;  // analog value
2int index=1;
3byte sntmsg[6];  // vector  to send
4
5/* sntmsg
6sntmsg is a 6 bytes vector:
71st byte is always 0xFF  and it is used as a check
82nd to 6th bytes contain 4 analog values read form  the arduino input A0 and converted into 10 bit numbers:
9
102nd byte: most significant  8 bits of the 1st analog value
113rd byte: least significant 2 bits of the 1st  analog value + most significant 6 bits of the 2nd analog value
124th byte: least  significant 4 bits of the 2nd analog value + most significant 4 bits of the 3rd  analog value
135th byte: least significant 6 bits of the 3rd analog value + most  significant 2 bits of the 4th analog value
146th byte: least significant 8 bits  of the 4th analog value
15*/
16
17void setup() {
18  
19 sntmsg[0] = 0xFF;  // byte1: check
20
21Serial.begin(9600); // initialization serial
22 
23noInterrupts();  // interrupts OFF
24
25//set timer1 interrupt at 600 Hz
26  TCCR1A = 0;// set  entire TCCR1A register to 0
27  TCCR1B = 0;// same for TCCR1B
28  TCNT1  = 0;//initialize  counter value to 0
29  // set compare match register for 1hz increments
30  OCR1A  = 416; // = [(16*10^6) / (600*64)]- 1    (must be <65536)
31  // turn on CTC mode
32  TCCR1B |= (1 << WGM12);
33  // Set CS10 and CS12 bits for 64 prescaler
34  TCCR1B  |= (1 << CS11) | (1 << CS10);;  
35  // enable timer compare interrupt
36  TIMSK1  |= (1 << OCIE1A);
37
38  interrupts();  // interrupts ON
39
40}
41
42ISR(TIMER1_COMPA_vect){  //timer1 interrupt 600Hz 
43
44  // read analog value
45  value = analogRead(A0);  // read analog value
46
47 switch (index) {
48
49    case 1:
50
51sntmsg[1]=  (byte) (value >> 2); // most significant 8 bits of the 1st analog value
52sntmsg[2]=  (byte) (value << 6); // least significant 2 bits of the 1st analog value
53++index;
54      break;
55
56    case 2:
57    
58//most significant 6 bits of the 2nd  analog value
59bitWrite(sntmsg[2], 5, bitRead(value, 9));
60bitWrite(sntmsg[2],  4, bitRead(value, 8));
61bitWrite(sntmsg[2], 3, bitRead(value, 7));
62bitWrite(sntmsg[2],  2, bitRead(value, 6));
63bitWrite(sntmsg[2], 1, bitRead(value, 5));
64bitWrite(sntmsg[2],  0, bitRead(value, 4));
65
66sntmsg[3]= (byte) (value << 4); // least significant  4 bits of the 2nd analog value
67++index;    
68      break;
69
70    case 3:
71
72//  most significant 4 bits of the 3rd analog value
73bitWrite(sntmsg[3], 3, bitRead(value,  9));
74bitWrite(sntmsg[3], 2, bitRead(value, 8));
75bitWrite(sntmsg[3], 1, bitRead(value,  7));
76bitWrite(sntmsg[3], 0, bitRead(value, 6));
77
78sntmsg[4]= (byte) (value  << 2);  // least significant 6 bits of the 3rd analog value
79++index;    
80      break;
81
82    case 4:
83
84// most significant 2 bits of the 4th analog  value
85bitWrite(sntmsg[4], 1, bitRead(value, 9));
86bitWrite(sntmsg[4], 0, bitRead(value,  8));
87
88sntmsg[5]= (byte) (value); // least significant 8 bits of the 4th analog  value
89index=1;    
90
91Serial.write(sntmsg,6);  // send value
92
93      break;
94
95  }  // end switch
96
97}  // end timer1 interrupt 600Hz 
98
99
100void loop()  {
101}
102

1int value=0;  // analog value
2int index=1;
3byte sntmsg[6];  // vector
4  to send
5
6/* sntmsg
7sntmsg is a 6 bytes vector:
81st byte is always 0xFF
9  and it is used as a check
102nd to 6th bytes contain 4 analog values read form
11  the arduino input A0 and converted into 10 bit numbers:
12
132nd byte: most significant
14  8 bits of the 1st analog value
153rd byte: least significant 2 bits of the 1st
16  analog value + most significant 6 bits of the 2nd analog value
174th byte: least
18  significant 4 bits of the 2nd analog value + most significant 4 bits of the 3rd
19  analog value
205th byte: least significant 6 bits of the 3rd analog value + most
21  significant 2 bits of the 4th analog value
226th byte: least significant 8 bits
23  of the 4th analog value
24*/
25
26void setup() {
27  
28 sntmsg[0] = 0xFF;
29  // byte1: check
30
31Serial.begin(9600); // initialization serial
32 
33noInterrupts();
34  // interrupts OFF
35
36//set timer1 interrupt at 600 Hz
37  TCCR1A = 0;// set
38  entire TCCR1A register to 0
39  TCCR1B = 0;// same for TCCR1B
40  TCNT1  = 0;//initialize
41  counter value to 0
42  // set compare match register for 1hz increments
43  OCR1A
44  = 416; // = [(16*10^6) / (600*64)]- 1    (must be <65536)
45  // turn on CTC mode
46
47  TCCR1B |= (1 << WGM12);
48  // Set CS10 and CS12 bits for 64 prescaler
49  TCCR1B
50  |= (1 << CS11) | (1 << CS10);;  
51  // enable timer compare interrupt
52  TIMSK1
53  |= (1 << OCIE1A);
54
55  interrupts();  // interrupts ON
56
57}
58
59ISR(TIMER1_COMPA_vect){
60  //timer1 interrupt 600Hz 
61
62  // read analog value
63  value = analogRead(A0);
64  // read analog value
65
66 switch (index) {
67
68    case 1:
69
70sntmsg[1]=
71  (byte) (value >> 2); // most significant 8 bits of the 1st analog value
72sntmsg[2]=
73  (byte) (value << 6); // least significant 2 bits of the 1st analog value
74++index;
75
76      break;
77
78    case 2:
79    
80//most significant 6 bits of the 2nd
81  analog value
82bitWrite(sntmsg[2], 5, bitRead(value, 9));
83bitWrite(sntmsg[2],
84  4, bitRead(value, 8));
85bitWrite(sntmsg[2], 3, bitRead(value, 7));
86bitWrite(sntmsg[2],
87  2, bitRead(value, 6));
88bitWrite(sntmsg[2], 1, bitRead(value, 5));
89bitWrite(sntmsg[2],
90  0, bitRead(value, 4));
91
92sntmsg[3]= (byte) (value << 4); // least significant
93  4 bits of the 2nd analog value
94++index;    
95      break;
96
97    case 3:
98
99//
100  most significant 4 bits of the 3rd analog value
101bitWrite(sntmsg[3], 3, bitRead(value,
102  9));
103bitWrite(sntmsg[3], 2, bitRead(value, 8));
104bitWrite(sntmsg[3], 1, bitRead(value,
105  7));
106bitWrite(sntmsg[3], 0, bitRead(value, 6));
107
108sntmsg[4]= (byte) (value
109  << 2);  // least significant 6 bits of the 3rd analog value
110++index;    
111
112      break;
113
114    case 4:
115
116// most significant 2 bits of the 4th analog
117  value
118bitWrite(sntmsg[4], 1, bitRead(value, 9));
119bitWrite(sntmsg[4], 0, bitRead(value,
120  8));
121
122sntmsg[5]= (byte) (value); // least significant 8 bits of the 4th analog
123  value
124index=1;    
125
126Serial.write(sntmsg,6);  // send value
127
128      break;
129
130
131  }  // end switch
132
133}  // end timer1 interrupt 600Hz 
134
135
136void loop()
137  {
138}
139