Introduction: Pocket ECG Monitor

Well, what is ECG?

According to the American Heart Association, it is a test that measures the electrical activity of the heartbeat. With each beat, an electrical impulse (or “wave”) travels through the heart. This wave causes the muscle to squeeze and pump blood from the heart. A normal heartbeat on ECG will show the timing of the top and lower chambers.

Why would you need this device?

This is something an important question, so to answer that in short, abnormality in ECG signals will sometimes lead to HEART ATTACK/myocardial infarction. Hence it's better to detect/monitor such abnormality prior to the effect.


You would need these to complete your DIY ECG Monitor

Step 1: About Authors

Yeah, finally we got some space to tell you about us.

😜 There is nothing much to say.

Can find us on Github, Sameer & Sanyam.

Step 2: Schematic

You can find the connections in the images attached.

One shows the graphical representation of connections and the other with pin descriptions.

Step 3: Required Software

Just have to upload the code using Arduino IDE to your NodeMcu / ESP -01 and download the application on your android mobile.

The code can be downloaded from here.

The android application can be downloaded from here.

To learn more about the hardware used can refer the following links:

Step 4: Setting Up Arduino IDE

Arduino IDE by default doesn't have the required board files which are used to program NodeMCU. Thus you need to follow some steps to add the libraries used to program NodeMCU using Arduino IDE.

The exact procedure is available here. For detailed information can refer this also.

Step 5: App Interface

Here are some images to show the Application interface and what all is available in the app.

Step 6: How to Use It on the GO!

  1. Make Hotspot from your Android Phone.
  2. NodeMCU will automatically connect to the hotspot (You need to mention proper SSID and Password in the code)
  3. Open the App on your Phone.
  4. Enter the IP address of NodeMCU in the textbox below.
  5. Connect the probes to the body.
  6. Wait for the sensor to plot the graph. (Takes a minute or two)
  7. Use Share button to send the graph to your health associates.

Voila your DIY On the Go ECG is ready.

Step 7: Taking This Project Further.

So making an ECG reader was fun but how about making a complete doctor's kit?

It can have,

  • Pulse Oximeter & Heart Rate Sensor
  • Temperature Sensor
  • Blood Pressure Sensor
  • Further App update
  • and many more...

To put everything in the box, the user can also print the custom box as 3D printed, depending upon the pocket or place where he/she needs to place the system. Check out the design file, can be editable as per the choice/need.

The possibilities are endless and we are here to help you. Feel free to contact us here on Instructables or on GitHub.

The complete repository can be found at this link.

Pocket-Sized Speed Challenge

Participated in the
Pocket-Sized Speed Challenge