Paragon Project: The Worst Smart Watch Ever

The Worst Smart Watch Ever Title Image

Sometimes in life, the worst is the best. And often with maker projects, the most fun way to do something is also the worst way. That’s undoubtedly the case with this atypical Paragon Project: the worst smart watch ever, put together by one of our favorite tech YouTubers – Low Level Learning.

Based on the Arduino Uno R4 with WiFi, Low Level Learning created an oversized, uncomfortable, poorly set-up smart watch and it’s great.

It tells the time and your heart rate directly on the built-in LEDs on the Arduino.


For this project, you’ll need an Arduino Uno R4 with WiFi, a heart rate monitor, a battery, a strap and case, and some duct tape.

The build is no sweat.

Step one: put the Arduino is a plastic case and run a strap through it. Stick that on your wrist.

Step two: delicately place the heart rate monitor and battery next to each other and then DUCT TAPE THAT TO YOUR ARM.

Bada bing bada boom. You’re ready to go.


I think the really fun part of all of this is the brilliance of the software to make this thing run (as is usually the case with Low Level Learning’s videos).

Heart Rate Monitor Code for the Worst Smart Watch Ever
The Heart Rate Monitor Code.
Credit: Low Level Learning.

First, as described in the video, it’s necessary to set up the Network Time Protocol (NTP) through the ESP32 chip’s SDK on the Arduino Uno. You initialize a buffer and then create a User Datagram Protocol (UDP) packet. That packet will contain the NTP data.

Really, in theory, all you need for this project is actually the ESP32, because that’s what’s running all the code. But, if you want that cool display, you’ll need the Arduino.

Next, you’ll need to set up the LED matrix to convert the NTP into something viable for the display.

The third step is hooking up a heart rate monitor to the Arduino in order to make it truly a smart watch. In the video, Low Level Learning mentions that heart rate monitors are green, because they output how much light they see when the light bounces off of skin. And green is the opposite color of blood.

It’s always great when people answer questions you never even thought to ask, like: why is my smart watch’s light green?

Anyway, the fourth step is to write code to figure out how much light is bouncing off of your skin in order to determine your heart rate. This step is my favorite for Low Level Learning’s ingenuity: figuring out the top and bottom levels of an analogue output and eventually converting it to a beats-per-minute integer.

Oh, and did I mention that you can’t go anywhere with it, because it’s dependent on a WiFi connection?

So there you have it – the worst smart watch ever in four steps. Be sure to check out the video:

And do let us know if you decide to create your own – we’ll gladly feature it in a follow-up post!

You can see more Paragon Projects that we’ve featured in this series by clicking here.

And, as always, if you’ve got any questions or if you’d like to suggest a project for this series, just comment below!


  1. Micheal O'Reilly on August 8, 2023 at 2:45 pm

    Say no to youtube!

    • Adam on August 8, 2023 at 2:57 pm

      Why’s that, Michael?

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