Find My Things

ESP8366-based Object Tracker

Rohan Barnwal

Issue 48, July 2021

Inspired by the Apple AirTag tracking device, a 16-year-old maker reached for his NodeMCU board to make his own.

When we put the call out for our readers to submit their projects to be featured in our magazine, young Rohan jumped at the chance. Rohan is just 16 years old and making some exciting projects with Arduino microcontrollers. In this build, Rohan has made a portable object locator using an ESP8266 NodeMCU and some commonly available components. We caught up with Rohan to find out more.

Thank you for sharing your project with us. Please introduce yourself to our readers.

Namaste (Hello in Hindi), my name is Rohan Barnwal. I am 16 years old and I am from India. I love to create electronic related things using microcontrollers and microprocessors and enjoy demonstrating how I make these projects on my YouTube channel named Arduino Boy.

You’ve been busy going by the many videos on your channel. What was it that first got you interested in electronics?

I was in 3rd standard at that time my father gave me a toy car that had only an on and off button. I wondered how this car started running by just pressing a button. This made me curious, so that night I asked my father how this car works.

He told me that it has a motor that runs on power provided from a battery and that the button in it was used to break or join the circuit. After that, I started to research these things and after some time I built my very own car. As I got older, I worked on microcontrollers and microprocessors, and till now I have made over 200 projects with them.

What was the reason behind making your own version of an Air Tag?

I got the inspiration to make this project after the Apple event on 23 April 2021 where Apple launched one of their product, which is named as AirTag. The AirTag is a button-like device under which you can find your keys or your belongings. It is even small enough to keep it in your wallet or purse like a key ring or coin. When you click on the play sound button, the AirTag produces a sound to help you find that lost thing. Being into Arduino, I thought why not make it from NodeMCU, which is what I succeeded to do.

We’re always using the find my phone function to locate our phone in the office. Finding other misplaced belongings sounds like a great idea. What parts does your project use?

The hardware was a NodeMCU, buzzer, mini breadboard and jumper wires. Instead of a breadboard, you could solder it directly to your NodeMCU Board as well.

The software I used was the Arduino IDE and Blynk Application

How is it powered, and how long would it run for on battery power?

My prototype was powered using a 9V Alkaline battery which ran up to 2-3 days.

Prototype using a 9V battery

However, I recently changed it to a 3.7V 1000mAh rechargeable lightweight lithium battery. I charge that using a TP4056 1A Li-ion battery charging board. A full charge runs up to 5 hours but I am working on it so that it can last even longer.

Build using a rechargeable Li-ion battery

A 9V battery is a quick and easy power source for a prototype, but obviously not practical for long term use. Tell us about the code.

The program came from the example in Blynk Library.

#define BLYNK_PRINT Serial
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "YourAuthToken";
// Your WiFi credentials.
// Set password to "" for open networks.
char ssid[] = "YourNetworkName";
char pass[] = "YourPassword";
void setup()
  // Debug console
  Blynk.begin(auth, ssid, pass);
  // You can also specify server:
  //Blynk.begin(auth, ssid, pass, 
"blynk-cloud.com", 80);
  //Blynk.begin(auth, ssid, pass, IPAddress(192,168,1,100), 8080);
void loop()

Example code in applications can certainly speed up the development time. What design challenges did you need to overcome?

I tried my best to make it as small as possible but with the Covid19 spreading badly all over the world, many stores and services are closed. I wanted to make it smaller by implementing this on a PCB but couldn’t access a PCB in time.

That’s unfortunate. Hopefully, you can access more maker goodies soon. Do you have any plans to modify it any further or make it into an enclosure?

Yes, I have some plans to modify it:

  1. As I mentioned earlier, I will make it as small as possible.
  2. I will also try to increase its range
  3. I will also add location or GPS feature so that owner of that can navigate to its product.

Great. All good objectives to challenge you. If you were to start again, what would you do differently?

If I was to make it again I would first think more about its design, about its range, etc.

If our readers want to make one for themselves, where can they find the code and wiring diagram?

If they want to make this project, then they can check out the build instruction on my Hackster.io page: https://www.hackster.io/ItsArduinoBoy/create-your-own-apple-airtag-f28559

My YouTube video about the build can also be found here: https://youtu.be/iWB-D-H4Y5g

Thank you for sharing your project with us, Rohan. We look forward to seeing what you design next.