Pulse sensor amped was inaccurate when work with ESP 8266

[LanceLDY]

If i did't connect to esp8266, my pulse sensor can take the accurate reading(60-90). Once it connect to the esp 8266, the reading is around 90-150. I also don't know what is the problem... Hope you guys can help me solve the issue. Thanks! Below is the code and the circuit diagram (take from online article that I refer to)...

include

define DEBUG true

include

include

LiquidCrystal lcd(12,11,5,4,3,2); SoftwareSerial esp8266(9,10); /-----------------ESP8266 Serial WiFi Module---------------/ String SSID ="vivo V3Max"; String PASS="12345678";

define IP "184.106.153.149"// thingspeak.com ip

String msg = "GET /update?key=SZDRPGCYMCSNT43W&field1="; //change it with your key... /-----------------------------------------------------------/ //Variables boolean halo = false; float temp; int hum; String tempC; int error; int pulsePin = 0; // Pulse Sensor purple wire connected to analog pin 0 int blinkPin = 13; // pin to blink led at each beat int fadePin = 5; int fadeRate = 0; // Volatile Variables, used in the interrupt service routine! volatile int BPM; // int that holds raw Analog in 0. updated every 2mS volatile int Signal; // holds the incoming raw data volatile int IBI = 600; // int that holds the time interval between beats! Must be seeded! volatile boolean Pulse = false; // "True" when heartbeat is detected. "False" when not a "live beat". volatile boolean QS = false; // becomes true when Arduino finds a beat. // Regards Serial OutPut -- Set This Up to your needs static boolean serialVisual = true; // Set to 'false' by Default. Re-set to 'true' to see Arduino Serial Monitor ASCII Visual Pulse volatile int rate[10]; // array to hold last ten IBI values volatile unsigned long sampleCounter = 0; // used to determine pulse timing volatile unsigned long lastBeatTime = 0; // used to find IBI volatile int P =512; // used to find peak in pulse wave, seeded volatile int T = 512; // used to find trough in pulse wave, seeded volatile int thresh = 525; // used to find instant moment of heart beat, seeded volatile int amp = 100; // used to hold amplitude of pulse waveform, seeded volatile boolean firstBeat = true; // used to seed rate array so we startup with reasonable BPM volatile boolean secondBeat = false; // used to seed rate array so we startup with reasonable BPM void setup() { pinMode(6,OUTPUT); digitalWrite(6,HIGH); pinMode(7,INPUT_PULLUP); digitalWrite(7,HIGH);

lcd.begin(16, 2); lcd.print("wait a moment..."); delay(100); lcd.setCursor(0,1); lcd.print("Connecting..."); delay(1000); Serial.begin(9600); //or use default 115200. esp8266.begin(9600); Serial.println("AT"); esp8266.println("AT"); delay(3000); if(esp8266.find((char*)"OK")){ connectWiFi();

} interruptSetup(); } void loop(){ start: //label error=0; lcd.clear(); lcd.setCursor(0, 0); lcd.print("BPM = "); lcd.print(BPM); delay(1000); button(); updatebeat(); //Resend if transmission is not completed if (error==1){ goto start; //go to label "start" } delay(2000); //Update every 1 sec }

void button(){ if(digitalRead(7) != HIGH){

halo = !halo;
digitalWrite(6,halo);

//delay (3000);

} else{ if(digitalRead(6)== true){ BPM=0; lcd.clear(); lcd.setCursor(0, 0); // set the cursor to column 0, line 2 lcd.print("BPM = "); lcd.print(BPM);

//delay(1000); } } }

boolean connectWiFi(){ Serial.println("AT+CWMODE=1"); esp8266.println("AT+CWMODE=1"); delay(2000); String cmd = "AT+CWJAP=\"" + SSID+"\",\"" + PASS + "\""; Serial.println(cmd); esp8266.println(cmd); delay(3000); if(esp8266.find((char*)"OK")){ Serial.println("OK"); return true;

}else{ return false; } }

void updatebeat(){ String cmd = "AT+CIPSTART=\"TCP\",\""; cmd += IP; cmd += "\",80"; Serial.println(cmd); esp8266.println(cmd); delay(5000); if(esp8266.find((char)"Error")){ return; } cmd = msg ; cmd += "&field1=";
cmd += BPM; cmd += "\r\n"; Serial.print("AT+CIPSEND="); esp8266.print("AT+CIPSEND="); Serial.println(cmd.length()); esp8266.println(cmd.length()); if(esp8266.find((char)">")){ Serial.print(cmd); esp8266.print(cmd); } else{ Serial.println("AT+CIPCLOSE"); esp8266.println("AT+CIPCLOSE");

//Resend...
error=1;

} } void interruptSetup(){
TCCR2A = 0x02; // DISABLE PWM ON DIGITAL PINS 3 AND 11, AND GO INTO CTC MODE TCCR2B = 0x06; // DON'T FORCE COMPARE, 256 PRESCALER OCR2A = 0X7C; // SET THE TOP OF THE COUNT TO 124 FOR 500Hz SAMPLE RATE TIMSK2 = 0x02; // ENABLE INTERRUPT ON MATCH BETWEEN TIMER2 AND OCR2A sei(); // MAKE SURE GLOBAL INTERRUPTS ARE ENABLED
} ISR(TIMER2_COMPA_vect){ // triggered when Timer2 counts to 124 cli(); // disable interrupts while we do this Signal = analogRead(pulsePin); // read the Pulse Sensor sampleCounter += 2; // keep track of the time in mS int N = sampleCounter - lastBeatTime; // monitor the time since the last beat to avoid noise // find the peak and trough of the pulse wave if(Signal < thresh && N > (IBI/5)3){ // avoid dichrotic noise by waiting 3/5 of last IBI if (Signal < T){ // T is the trough T = Signal; // keep track of lowest point in pulse wave } } if(Signal > thresh && Signal > P){ // thresh condition helps avoid noise P = Signal; // P is the peak } // keep track of highest point in pulse wave // NOW IT'S TIME TO LOOK FOR THE HEART BEAT // signal surges up in value every time there is a pulse if (N > 250){ // avoid high frequency noise if ( (Signal > thresh) && (Pulse == false) && (N > (IBI/5)3) ){
Pulse = true; // set the Pulse flag when there is a pulse digitalWrite(blinkPin,HIGH); // turn on pin 13 LED IBI = sampleCounter - lastBeatTime; // time between beats in mS lastBeatTime = sampleCounter; // keep track of time for next pulse if(secondBeat){ // if this is the second beat secondBeat = false; // clear secondBeat flag for(int i=0; i<=9; i++){ // seed the running total to get a realistic BPM at startup rate[i] = IBI;
} } if(firstBeat){ // if it's the first time beat is found firstBeat = false; // clear firstBeat flag secondBeat = true; // set the second beat flag sei(); // enable interrupts again return; // IBI value is unreliable so discard it }
word runningTotal = 0; // clear the runningTotal variable
for(int i=0; i<=8; i++){ // shift data in the rate array rate[i] = rate[i+1]; // and drop the oldest IBI value runningTotal += rate[i]; // add up the 9 oldest IBI values } rate[9] = IBI; // add the latest IBI to the rate array runningTotal += rate[9]; // add the latest IBI to runningTotal runningTotal /= 10; // average the last 10 IBI values BPM = 60000/runningTotal; // how many beats can fit into a minute? that's BPM! QS = true; // set Quantified Self flag // QS FLAG IS NOT CLEARED INSIDE THIS ISR }
} if (Signal < thresh && Pulse == true){ // when the values are going down, the beat is over digitalWrite(blinkPin,LOW); // turn off pin 13 LED Pulse = false; // reset the Pulse flag so we can do it again amp = P - T; // get amplitude of the pulse wave thresh = amp/2 + T; // set thresh at 50% of the amplitude P = thresh; // reset these for next time T = thresh; } if (N > 2500){ // if 2.5 seconds go by without a beat thresh = 512; // set thresh default P = 512; // set P default T = 512; // set T default
firstBeat = true; // set these to avoid noise secondBeat = false; // when we get the heartbeat back lastBeatTime = sampleCounter; // bring the lastBeatTime up to date
} sei();
// enable interrupts when youre done! }// end isr

[LanceLDY]

I also had the button problem. I need to press for a while, so that my button will on the pulse sensor

[devyte]

@LanceLDY your sketch shows AT cmds for the ESP. I think you're in the wrong repo, this is a direct development firmware, not the AT firmware. I suggest asking at a forum instead of an issue tracker for a repo. Closing.