Tiny Motion Detection Alarm Does The Trick

February 24, 2024 by Kristina Panos 6 Comments

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.

Automatic Airsoft Turret

October 25, 2012 by Jeremy Cook 8 Comments

[Valentin] wrote in to tell us about his automatic Airsoft turret. What it lacks in accuracy, it more than makes up for with sheer volume of fire. The pellet container is able to hold 500 6mm bbs, so make sure to get out of the way after this device is armed.

The device itself is a great example of physical hacking, harvesting parts from a motion sensor as well as a G35 gearbox from Airsoft gun. For physical rotation, it uses a reversing platform reminiscent of the way a useless machine works (see this [HAD] article for more useless machine info). Even if you’re not interested in building a turret, this machine employs some very interesting concepts, so it’s worth checking out.

When live action Team Fortress becomes a fad, maybe these will make an appearance. Until then, check out the video of this turret after the break, or check out the original article for more pictures and video! Continue reading “Automatic Airsoft Turret” →

Motion Detecting Window Closers Keep Train Noise At Bay

September 13, 2011 by Mike Nathan 57 Comments

motion_detecting_window_closers

[Ed Rogers] has the unfortunate privilege of living right next to a set of train tracks, and as a man who holds his sleep in high regard, he needed to find a way to keep the noise in his bedroom to a minimum. To combat the sound of passing trains, he built himself a system that automatically closes his windows when a train passes by his apartment.

The setup relies on a web cam, which uses motion-sensing software to detect a passing train. The video is analyzed by a computer in his room which passes a message to an Arduino when a train is near. The Arduino then sends a pair of window mounted linear actuators into action, slowly (and quietly) shutting his windows.

The linear actuators move pretty slowly as you can see in the video below, but we doubt that matters. Since it looks like [Ed] lives in a slow zone, it likely takes quite a bit of time for a freight train to pass, making the 40-second closing period more than reasonable.

Continue reading “Motion Detecting Window Closers Keep Train Noise At Bay” →

Security System Gives You A Call When It Senses Intruders

September 8, 2011 by Mike Nathan 13 Comments

gsm_motion_detector_alarm_system

[Dimitris] decided to build a homemade alarm system, but instead of triggering a siren, sending an SMS message, or Tweeting about an intrusion, he preferred that his system call him when there was trouble afoot. He says that he preferred a call over text messaging because there are no charges associated with the call if the recipient does not pick up the line, which is not the case with SMS.

The system is based around an off the shelf motion detector that was hacked to work with an old mobile phone. The motion detector originally triggered a siren, but he stripped out the speaker and wired it to a bare bones Arduino board he constructed. The Arduino was in turn connected to the serial port of an unused Ericssson T10s mobile phone. This allows the Arduino to call his mobile phone whenever the motion detector senses movement.

The system looks to be quite useful, and while [Dimitris] didn’t include all of the code he used, he says others should be able to replicate his work without too much trouble.