Tiny Motion Detection Alarm Does The Trick

If you have mischievous children or forgetful elderly in your life, you might want to build a couple of these tiny motion detection alarms to help keep them out of harm’s way. Maybe you want to keep yourself out of the cookie jar. We say good for you.

But you could always put one of these alarms on a window, a drawer, or anything else you don’t want opened or moved. The MPU6050 3-axis IMU makes sure that any way the chosen item gets jostled, that alarm is going off.

As you may have guessed, there isn’t much more to this build — the brain is a Seeed Xiao ESP32-C3, and there’s a buzzer, a battery, a switch, and a push button to program it.

The cool thing about using an ESP32-C3 is that [gokux] can use these for other things, like performing a task when motion is detected. If you do want to build yourself a couple of these, here are step-by-step instructions.

If you’d rather detect motion in the vicinity, here’s a PIR-based solution.

Swatch Internet-Time Clock Doesn’t Miss A Beat

The thing about human invention is that occasionally, two or more people think of an idea around the same time, and it’s difficult to determine who was first. Such is the case with Swatch’s Internet time, which is told in something called “.beats”. Rather than using hours and minutes, the solar day in the .beat system is divided into 1,000 parts equal to one minute in the French Revolutionary decimal time system, or 1 minute and 26.4 seconds of standard time.

Swatch came up with .beats to sell their special line of .beats watches. But they weren’t the only ones to divide the solar day this way. A few months before Swatch’s announcement of .beats time, a Argentinian drummer named [Charly Alberti] came up with the same idea and created a website for it to display the current Internet time of day.

The point of all this is that [Roni Bandini] has created an homage to both .beats and [Charly] in the form of a small clock. The main brain is a Seeed Studio Xiao nRF52840, with a Xiao TFT round display to show the time as well as a tribute to [Charly]. The 3D-printed stand incorporates a cylindrical power source. We think the black and white images, which [Roni] created with Dall-e, look fantastic.

Interestingly enough, the Xiao has no Internet connectivity; the time is set manually via hard-coded variable, and then the display’s RTC keeps track of the seconds and convert them to Internet time. Check out the brief build video after the break.

Interested in regular old metric time? Here’s a modern metric clock.

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