Pocket Nurse

This is a micro health care station which has some sensors to measure vital signs (body temperature, blood pressure and hearth rate)

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This project intends to develop a new way of making quick diagnosis using a portable device to measure the vital signs.

Using a nano arduino or a Adafruit Pro Trinket and a bunch of sensors (temperature, infrarred and preasure) this device can be capable of give a quick diagnosis to a patient that needs urgent care, or maybe a polyclinic that wants to improve their time of attention.

Using a bluetooth and a SD memory card, all the collected data from the arduino or Adafruit could be processed by a computer to have real time measure or stored (in the SD or the PC) for further use.

Also it will have a function to weight someone till 100 Kg.

I am just starting with the project, so more updates will come soon. I only included the schematics of the infrarred sensor.

Referring to the energy source, I think appropiate to use a 5V small lithium battery connected to a small solar pannel to charge it.So there are not excuses to start using this device, you just need sun.



The main idea is represented in the following image. It's a diagram of the different connections between the Nano arduino and the other devices, such as the battery, sensors and devices who storage information.

The input devices are:

  • The pulse detector
  • Thermometer
  • Scales
  • Pressure gauge
  • Battery

The output devices are:

  • LCD 16x2 with backlight
  • SD Memory
  • Bluetooth module

The connections are these. Almost all the arduino digital pins are occupied. There is no place to connect a Bluetooth module. So it will be eliminated.


The Pocket Nurse is intended to work as an artifact that measures the pressure, weight, temperature and pulse from a person. It eases the way of making a diagnosis and puts within reach of their hand a lot of data from the symptoms.

If you want to have al this data in a computer you just remove the SD Card, or turn on the Bluetooth module and you process that in a plain text archive generated by the arduino. Also there would be an option of viewing the data in real time, except form the blood preasure.

Another way to access this information in real time is to watch the LCD screen and take note. Because it will display de the information there.


Temperature: 36,7°C
Pulsations per minute: 110

The display has only two lines were the text could be displayed, so the text would be displayed 10 seconds and the other text other 10 seconds and so on.


Memory Card

There is where the information will be stored. As long as the board gather data, the important one will be stored here.

I had no money to afford an SD card shield, so I have built it by myself and with a little help from this tutorial.

The photo shows the pin assignament for the SD module.Also it is needed a code to me make it work that is HERE.

LCD 16x2

Other important part of this project is the screen, there will be displayed the data. All you need to know is how to solder it properly the pins to the screen and how to connect it to the board.

The code to make the LCD 16x2 work is HERE.

Temperature Sensor

To measure the body temperature is necesary a digital temperature measure device, as the TMP36GZ.

My camera does not provide so much resolution but it shows that is a small component.

The code to make it work and watch the temperature in the serial log is HERE.

Pulse detector

Other function of this pocket nurse was the capability of meauring the pulse. So with a LDR and a green ledit could be possible.

This photo shows the LDR and the green high bright led connected. The code to make it work is HERE.

Pulse detector WORKING!


After trying some codes and addapting them to my components I have reached something. The temperature sensor works fine and it mesures the temperature correctly. It has a Time counter because it is needed to have a correct measure of the temperature, you must wait around 3 to 4 minutes (180 to 240 seconds).

The display shows something like this:

Corporal Temp:
29.98 ºC Time:128 s

This other photo shows that I'm using a ATmega 328.

The final code

#include <LiquidCrystal.h>
#include <SD.h>

LiquidCrystal lcd(5, 3, 6, 9, 8, 7);

const int chipSelect = 4;

float voltaje;
float grados;
float pulsostot;
int i=0;
int pulsos;
int cont = 1;
int pulsoini[1000];

void setup ()

  pinMode(10, OUTPUT);
  Serial.begin(9600); //Iniciamos la comunicación con el puerto serial
  if (!SD.begin(chipSelect)){
    lcd.print("Error reading SD.");

void loop() {
File dataFile ="PocketNurse.txt", FILE_WRITE);  

  voltaje = analogRead(5) * 0.004882814;                         
  grados = (voltaje - 0.5) * 100.0;
  lcd.print("Body Temp:");

  pulsostot= i;
  // if (pulsoini[cont] != pulsoini[cont--]){

 if (dataFile) {
    // Escribimos en el fichero "POT: "
    dataFile.print("Temp: ");
 // A continuacion...
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  • 1 × Arduino Nano Nano Arduino
  • 2 × Resistor 10 MOhm and 220 Ohm
  • 1 × Battery Lithium
  • 1 × Solar Panel Small one (Really small)
  • 1 × Temperature Sensor TMP36

View all 11 components

  • The final arrival

    Martin Ferreira01/02/2015 at 16:28 0 comments

    All the materials needed have come! This is the final arrival.

    In this picture we could see (listed form above to below):

    • LCD 16x2
    • Rechargeable battery
    • Micro SD card Shiel for Arduino
    • LDR
    • Green high bright LED
    • Solar module 3,3 V
    • Arduino Nano ATmega 328 customed from China

  • New incomes

    Martin Ferreira12/29/2014 at 17:49 0 comments

    Well after waiting for weeks, I've received my displays.

    I must calibrate the contrast, but with a 4.7 kOhms resistor connected to ground it works great.

    There is a lot of cables around but they are connected in the right place.

    I will be waiting for the arrival of the ATmega328... I'm using a Arduino UNO meanwhile.

  • My mistake

    Martin Ferreira12/20/2014 at 01:11 0 comments

    According to the rules of the Trinket Everyday Carry Contest I must use a Pro Trinket. So while I'm waiting for the Pro Trinket I will be using my Nano Arduino. But it's temporary until I receive Pro Trinket.

    Also I'm still waiting for the main components...

  • Waiting for the components

    Martin Ferreira12/11/2014 at 02:47 0 comments


    I am waiting for the materials. I will be waiting till christmas I hope so, shipping to Uruguay could be cruel.

    Heart Beat Detector

    I found this image on the internet, and it describes how to build a heart beat detector. It uses an infrarred receiver (infrarred sensitive photoresistor as it´s shown in the picture), and a infrarred transmitter.

    The infrarred emitter sends a infrarred light through the finger (or some translucent part of the body), and with each pulsation of the hearth it reduces the intensity of the light that could pass. So the infrarred sensitive photoresistor receives a variable light on the other side of the finger, and when the intensity decreases there is a pulse.

    The nano arduino will count how many of these interruptions could be in a minute.

View all 4 project logs

  • 1
    Step 1

    First of all, when you want to start a project like this one, all you need to know is what it will do. As an example, if you want your project to measure temperature you need a temperature sensor (TMP36). Also if you want to measure the pulse you need a pulse detector (in this case there are pulse detector shields to buy, but they are expansive, so let's build one by ourself).

    And so on with other functions (sotorage the data in a SD or send it by bluetooth and print it in a LCD screen, and measure the blood preasure). All this data must be processed and organized, and there is where the Trinket Pro enters in the project.

    It's seems pretty intutive but it's important to emphazise on it.

  • 2
    Step 2

    When you got all the components you need to count the number of pins that will be used to connect to the Trinket Pro, in order to let it work correctly. If you exceed the number of pins in a project you need to erase some shield and sensors from the scheme.

    In this case I had some problems with my pins and sensors.

    As you can see, all the digital pins are occupied by the LCD 16x2 and the SD card shield. So there is no place for the Bluetooth module.

    But we have a lot of analog inputs free, only 2 are occupied by the LDR and the TMP36.
  • 3
    Step 3

    Everything it's ok, we have everything connected but, it needs to work with the Trinket Pro. This is where the programs start to take place. That's why I have created a GitHub Code for the Pocket Nurse.

    There you can find the testing codes for each shield and sensor. With this you could see if it works correctly. In this case I used a SD shield, LCD 16x2 Screen, TMP36 temperature sensor and a LDR with a green LED to measure the hearth rate.

    So, test each one, and if it works fine let's go on.

View all 4 instructions

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bijtaj wrote 06/13/2016 at 01:54 point

I see for your pulse detector, you have no amplifiers and filters (not even any digital ones in the code). How accurate and sensitive is the pulse detector that way? Also, did you set up your pulse detector for reflection (light reflects off of the skin down to the LDR; both LED and LDR below the finger) or transmission (light goes through the skin; finger in the middle of LED and LDR)? Will you be using IR light at all? How do you plan to measure blood pressure? Will you use Pulse Transit Time? I am working on a similar project using an Arduino Uno, #An Arduino-based Medical Tricorder, and maybe we could collaborate! 

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