The basic concept was to build a clock that would only display the time on command. In this case, that command would be a wave of a hand in front of the clock. The build is based around a Lilygo ESP32 T-Display unit, which combines the ESP32 with an LCD display and a battery management system. The ESP32’s WiFi connection provides accurate time via querying an NTP server. A passive infrared motion sensor is used to detect the motion of the user’s hand in front of the clock.
Working from home with regular video meetings has its challenges, especially if you add kids to the mix. To help avoid embarrassing situations, [Charitha Jayaweera] created Present!, a USB device to automatically turn of your camera and microphone if you suddenly need to leave your computer to maintain domestic order.
Present consists of just a PIR sensor and Arduino in a 3D printed enclosure to snap onto your monitor. When the PIR sensor no longer detects someone in range, it sends a notification over serial to a python script running on the PC to switch off the camera and microphone on Zoom (or another app). It can optionally turn these back on when you are seated again. The cheap HC-SR501 PIR module’s range can also be adjusted with a trimpot for your specific scenario. It should also be possible to shrink the device to the size of the PIR module, with a small custom PCB or one of the many tiny Arduino compatible dev boards.
While there are loads of impressive and complex projects here on Hackaday, sometimes it’s the simple ones that really speak to us. In this case we were presented with [Isabell Park]’s easy-to-follow instructable on how to build an anti-procrastination device.
On the hardware side there are no surprises, it consists of a PIR sensor connected to a NodeMCU microcontroller. It checks for a signal from the sensor, and if it’s triggered, it sends a command through the Adafruit IO libraries to IFTTT. On its own it could make for a decent movement alarm, but the part that makes the project interesting is how it’s applied to become a device to help with procrastination instead.
First, you put your phone in a jar along with the electronics and close it. Then, with everything configured, the circuit is powered on and stays vigilant for any movement inside the jar. Should you try to take your phone out of it for a quick social media break (which, if you’re like us, can turn into a few hours), IFTTT will be alerted and run through whatever script you have in place. In [Isabell]’s case, she suggests sending an SMS to a trusted contact to keep you in check.
Most of us currently have to deal with wearing face masks in our daily life. An experience that is not entirely pleasurable as it is more difficult to breathe under the mask and can become hot after a while. In addition, you have to take off the mask whenever you want to eat or drink. [DesignMaker] has attempted to solve these problems by creating a mask with an opening that shuts automatically when other people are nearby.
While homemade masks are usually made from fabric [DesignMaker]’s version is much more to a hacker’s taste and includes 3D-printed parts, an Arduino Nano, PIR sensors, an SG90 servo, and some Neopixels. [DesignMaker]’s background in industrial design certainly helped him when modeling the mask as it looks just plain awesome.
His goal was to use PIR sensors to detect when a person is moving nearby. The servo then shuts an opening located at the mouth part of the mask. However, he soon found out that the mask often shuts when nobody is around. The reason is that the sensor can be triggered by ambient IR radiation when it is moving by itself. In the end [DesignMaker] decided that having the mask shut when you are moving is not a bug, it’s a feature.
Of course, the mask is just a prop and should not be used as protective equipment. As shown in the video below, also the false triggering of the PIR sensors can be annoying at times. But [DesignMaker] is already thinking of improvements like having the mask properly sealed with fabric or replacing the PIR sensors by a camera with face detection.
If you want to learn how to sew a proper fabric face mask have a look here. It’s a lot less ridiculous, but a lot more effective. You can’t have everything.
The idea behind a dummy security camera is that people who are up to no good might think twice about doing anything to your property when they think they’re being recorded. Obviously a real security camera would be even better, but sometimes that’s just not economically or logistically possible. Admittedly they’re not always very convincing, but for a few bucks, hopefully it’s enough to make the bad guys think twice.
But what if that “fake” camera could do a little more than just look pretty up on the wall? [Chris Chimienti] thought he could improve the idea by adding some electronics that would notify him if motion was detected. As an added bonus, any would-be criminals who might be emboldened by the realization the camera itself is fake might find themselves in for a rude surprise when the notifications start firing off.
In the video after the break, [Chris] really takes his time walking the viewer through the disassembly of the dummy camera. As it turns out, these things look like they’d make excellent project enclosures; they come apart easily, have nothing but empty space inside, and even have an integrated battery compartment. That alone could be a useful tip to file away for the future.
He then goes on to explain how he added some smarts to this dummy camera. Up where the original “lens” was, he installed a PIR sensor, some white LEDs, a light sensor, and the original blinking red LED. All of this was mounted to a very slick 3D printed plate which integrates into the camera’s body perfectly. The new hardware is connected up to a similarly well mounted Wemos D1 Mini inside the camera. The rest of the video goes through every aspect of the software setup, which is sure to be of interest to anyone who’s ever thought of rolling their own IoT device.
Getting young kids excited about technology and engineering can be a challenge, and getting them interested in the environment isn’t exactly a walk in the park either. So any project that can get them simultaneously engaged in both is a considerable achievement, especially when they can do the work themselves and see how creating something can have a positive impact on their little corner of the world.
The heart of the system is an Adafruit Audio FX sound board, which has been loaded up with audio clips recorded by the students. The buttons on the front of the can trigger different messages about why it’s important to make sure trash is disposed of properly, and an internal switch allows the can to thank the user for their deposit when the lid has been opened.
A PIR sensor on the front of the can detects when somebody gets close, and plays a message reminding them to make use of the trash cans provided on the playground. It’s not everyday that a child has a garbage can talk to them, so we think this is a fantastic idea for getting a kid’s attention. In keeping with the ecological friendly theme, the whole system is powered by a small solar panel which charges an internal 3.7V LiPo battery with the help of an Adafruit PowerBoost 500.
Thieves beware. If you prowl around [Matthew Gaber]’s place, you get soaked by his motion activated super-squirter. Even if he’s not at home, he can aim and fire it remotely using an iPhone app. And for the record, a camera saves photos of your wetted-self to an SD card.
The whole security system is handled by three subsystems for target acquisition, photo documentation, and communications. The first subsystem is centered around an ESPino which utilizes a PIR sensor to detect motion. It then turns on a windscreen washer pump and uses pan and tilt servos to squirt water in a pattern toward the victim.
The target acquisition hardware also sends a message to the second subsystem, an ArduCAM ESP8266 UNO board. It takes a burst of photos using an ArduCAM Mini Camera mounted beside the squirter outlet. The UNO can also serve up a webpage with a collection of the photos.
The final subsystem is an iPhone app which talks to both the ESPino and the UNO board. It can remotely control the squirter and provide a video feed of what the camera sees.
One detail of the build we really enjoyed is the vacuum relief valve he fabricated himself. It prevents siphoning through the pump when it’s not on. Don’t miss a demo of the squirter in action after the break.