#pulse sensor

[ijtsrd]

Design and Implementation of Human Stress Detector

by Prajakta J. Jadhav | Shital S. Jadhav | Pravinkumar V. Gund | Mrs.Madhura G. Kulkarni" Design and Implementation of Human Stress Detector" 

Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-3 , April 2018, 

URL: http://www.ijtsrd.com/papers/ijtsrd11562.pdf  

Direct URL: http://www.ijtsrd.com/engineering/electronics-and-communication-engineering/11562/design-and-implementation-of-human-stress-detector/ prajakta-j-jadhav

paper publication for engineering, engineering journal, ugc approved journals for engineering

Today's life is full of frustration, deadlines and demands. For many people, stress is common that it has become an integral part of life. Stress is body's way of responding to any kind of demand and threat. When you feel threatened, your nervous system responds by re-leasing flood of stress hormones including adrenaline due to which body conductance changes, heart beat changes, blood pressure raises and breath quickness increases. They directly correlate the level of stress to one's emotion or mood [1]. In the proposed system heart beat rate, body temperature and moisture are the three informative signals that are used to determine the level of stress. 

[projetocoxinha]

Estamos um passo mais próximos de fazermos nosso projeto C.O.X.I.N.H.A. virar realidade, conseguimos fazer o nosso sensor de pulso funcionar graças a [1] e ele funcionou que é uma beleza, só falta dar aquela calibrada e entender melhor como ela funciona.

[1] : http://www.instructables.com/id/Pulse-Sensor-With-Arduino-Tutorial/

[reneeakers-blog]

Scoreboard Biofeedback System Looking and trailing different heart rate sensors was a positive and important research stage. Seeing how the visualisation of the numbers could affect the biofeedback reaction. This gave the design decision to not take this pulse sensor, pass the trailing stage. This would work well for physical fitness biofeedback. Research: https://circuitdigest.com/microcontroller-projects/heartbeat-monitor-project-using-arduino

[reneeakers-blog]

Pulse Sensory

Once gained the pulse sensory equipment, trailing visualisation of the heart beat and knowing it was mine, was an achievement. Driving passion to take the development from a line biofeedback system to beyond.

Correctly understanding the different stages and complexity of the heartbeat was visually being expressed simply with a line and a number.

Knowing this is just the begging is a positive start, but exploring more visualisation of the data is the next stage.

Research; https://youtu.be/82T_zBZQkOE

[yheyuky]

Sync

[yheyuky]

Sync pulse

[iwantdata]

Arduino Pulse Sensor Data Visualisation par mikebrondbjerg At a recent event, we visualised a number of audience members pulses using an Arduino pulse sensor. The following are series of unique prints we generated for each person.

[electricsuds]

Pulse Sensor on Adafruit GEMMA

(Updated with GitHub repo: https://github.com/victorbutler/gemma-heartbeat)

For the T-Shirt I'm making, (link) I needed a way to measure someone's pulse. The pulse sensor Adafruit sells has some example code that runs on a regular 5 volt Arduino, but GEMMA isn't your everyday Arduino clone. It runs on an ATtiny85 (vs ATmega328) and has some limitations. It runs at a lower voltage and has less timers.

To get the timers working, this is what you need to do. Find the following code in Interrupt.ino:

void interruptSetup(){ // Initializes Timer2 to throw an interrupt every 2mS. 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

And replace it with this:

void interruptSetup() { // Initializes Timer1 to throw an interrupt every 2mS. // The ATtiny85 datasheet (pages 89-92) really helped me out here - and lots of trial and error: http://www.atmel.com/images/atmel-2586-avr-8-bit-microcontroller-attiny25-attiny45-attiny85_datasheet.pdf TCCR1 = 0; TCCR1 |= _BV(CTC1); //clear timer1 when it matches the value in OCR1C TCCR1 |= _BV(CS12) | _BV(CS11) | _BV(CS10); //set prescaler to divide by 64 - 8MHz/64 = 125kHz frequency for each timer tick TIMSK |= _BV(OCIE1A); //enable interrupt when OCR1A matches the timer value /** * We can do some simple math here for timer calculations * GOAL: We want a 2ms trigger, which in Hertz is 500Hz (1/2ms) * What we have: 125khz timed clock (thanks to the 64 prescalar) * 125khz/500Hz = 250, so we need to count from 1 to 250 (or 0 to 249) and then execute our interrupt service routine */ OCR1A = 249; //set the match value for interrupt - 125kHz/250 = 500Hz = 2ms (don't forget we start at a zero count, not 1) OCR1C = 249; //and the same match value to clear the timer - otherwise it will continue to count and overflow sei(); // MAKE SURE GLOBAL INTERRUPTS ARE ENABLED } ISR(TIMER1_COMPA_vect){                         // triggered when Timer1 counts to 254

With this, your timer should fire as expected. Here's a link to the entire Interrupts.ino file.

I hope this helps anyone trying to port over the code to work with GEMMA. I didn't go through everything you need to do to convert the code, but this was the biggest hiccup I encountered.

As an aside, another pain in the ass was figuring out that the input from pin 2 is read in through pin 1 via analogRead(1). I figured this out late.

If requested, I can write a post outlining the entire process. Good luck!

Here’s the GitHub repository with the code that runs the Pulse Sensor Amped on the Adafruit Gemma.

https://github.com/victorbutler/gemma-heartbeat