Measuring the center of mass of the arrow arm, in its unfinished form, will be inaccurate, but we can come closer to being accurate if we place as many of the components on it before making our guess.
Be careful with the power connection of the LED strip. If you connect it to the 9V battery line, it will fry the LED, and the strip will be ruined.
The ground connection to the LED strip can be connected to any ground connection of this circuit. There is no danger of anything burning.
The 330 Ω resistor on the LED strip’s data pin acts like a tiny speed bump for the signal. It protects the LEDs by keeping the data signal from being too strong or too fast, which helps the strip work correctly and last longer.
Make sure the connection between the clock arm and the clock's body is strong. Otherwise, it may sleep when you turn it on.
The hall effect sensor can't detect a magnet, without there being one in the first place. While we can use glue or other ways of attaching a magnet to the clock face, we decided to use a second magnet on the other side of the face to hold the main one attached to it.
In this self-paced, beginner-friendly online course, you and your child will learn how to create a rotating LED strip display—a glowing clock that seems to paint time in mid-air. And don’t worry if you’ve never soldered, wired a circuit, or touched an Arduino before. We guide you from the very first step all the way to powering on your finished display.
By the end of this journey, you’ll both have learned real hands-on skills—like how to solder, drill clean mounting holes, read resistor color codes, and work with common electronic components—all while building something that looks impressively “advanced” but is totally achievable for beginners.
Before you jump into the build videos, this first lesson gives you a clear picture of what you're creating—and what materials you’ll need to make it happen. We want you to have full confidence in what you’re investing in. There are no surprise expenses later: everything required is listed upfront, along with tips on where to buy each part.