This Arduino Nano R4-controlled hourglass simulates sand with LEDs

Outside of playing board games, hourglasses are almost entirely pointless these days. And yet, they’re still incredibly satisfying. Watching the sand fall in a steady and consistent stream is downright mesmerizing. Sadly, you probably can’t make your own hourglass unless you happen to be very skilled at glassblowing. But you can create this LED hourglass with sand physics instead.

Four years ago, Edison Science Corner posted a video about a digital hourglass made with LED matrix panels and featuring simple physics for the falling sand. But as cool as that was, it had a foamboard case and wasn’t optimized for others to replicate. So, after receiving many requests, Edison Science Corner redesigned the hourglass with a 3D-printed enclosure to make the device easy to build.

Like the original, this has two LED matrix panels, each with a MAX7219 driver and an 8×8 grid of LEDs (available in amber, blue, or green). When flipped, the “sand” pixels will “flow” down from one matrix to the other. An Arduino Nano R4 board does the processing for that physics simulation and it detects the flip using an ADXL335 three-axis accelerometer. It can also detect rotation below 180 degrees and the sand will react accordingly. Power comes from a small lithium-ion battery, so the device works without a cable.

If you’d like to put together your own LED hourglass, you can do so using the provided files. Edison Science Corner is also selling kits and fully assembled devices.