A student once asked his lab instructor why his amplifier was oscillating. After looking at it and noting the wild construction, the instructor remarked, “A better question would be why shouldn’t it oscillate?” The truth of it is, our circuits generate noise and especially if they are oscillating anyway. Distortion and nonlinearities generate harmonics and other component imperfections also contribute.
[FesZ Electronics] has a great video series about noise in switching power supplies and the latest talks about the hot loop. If you want to improve the noise performance of your next design, these videos are well worth watching. You can see the hot loop video below.
We really liked the homebrew noise probes. In addition to real-world probing. The video also observes circuit operation under simulation. Even if you don’t care about noise performance, there’s a lot of good information about basic switching power supply design here.
You can see the difference in a PCB that has a small hot loop versus a very small hot loop. Something to think about next time you are laying out a power supply board.
If you want to dive deeper into noise simulation, we have a good read on that for you. Or ditch simulation, and make your own cheap probe with an SDR dongle.
Continue reading “EMC Tutorial Puts You In The Loop”
Eyeballs are often watching us, but they’re usually embedded in the skull of another human or animal. When they’re staring at you by themselves, they can be altogether more creepy. This Halloween project from [allpartscombined] aims to elicit that exact spooky vibe.
The project relies on a Kinect V2 to do body tracking. It feeds data to a Unity app that figures out how to aim the eyeball at any humans detected in the scene. The app sends angle data to an Arduino over serial, with the microcontroller generating the necessary signals to command servos which move the eyeball.
With tilt and pan servos fitted and the precision tracking from the Kinect data, the eye can be aimed at people in two dimensions. It’s significantly spookier than simply panning the eye back and forth.
The build was actually created by modifying an earlier project to create an airsoft turret, something we’ve seen a few times around these parts. Fundamentally, the tracking part is the same, just in this case, the eye doesn’t shoot at people… yet! Video after the break.
Continue reading “This Eyeball Watches You Thanks To Kinect Tracking”
Student and hacker [prusteen] recently fell in love with the Pomodoro method of time management. That’s where you concentrate on your task for 25 minutes, then take a five-minute break, and repeat this four times with a longer break at the end. Initially, [prusteen] was keeping track on their phone, but hated having to change the timer value between Pomodoros and break times. In order to keep the flow mode engaged, [prusteen] came up with this darling little study buddy that does it all with the push of a button.
By default, this tomato shows the current time, which we think is a handy and often-overlooked feature of Pomodoro timer builds. Press that momentary switch on the front, and it starts counting upward to 25 minutes. Then it beeps in stereo through a pair of buzzers when the time is up, and automatically starts a five-minute break timer. Press it again and the display goes back to clock mode, although judging by the code, doing this will cancel the timer.
Inside the juicy enclosure is an Arduino Nano, an RTC, and a 7-segment display. We love the attention to detail here, from the little green leaves on top to the anatomically-correct dimple on the underside. And we always like to see lids that snap on with magnets. So satisfying. Check out the brief demo after the break, which unfortunately does not include any lid-snapping action.
Do you need more interaction with your Pomodoro timer? Build yourself a pomo-dachi instead.
Continue reading “World’s Cutest Pomodoro Timer Is Also A Clock”
News from the wizarding world is a little hard to come by for common muggles, but [Deep Tronix] has brought us one step closer to our magical counterparts with their electronic replica of the Daily Prophet newspaper.
Those familiar with the Harry Potter series will no doubt be familiar with the Daily Prophet. In the films, the newspaper is especially eye-catching with its spooky animated images, a reflection of the magic present throughout the wizarding world. This was achieved with post-production special effects for the films, but this fan-made front page of the Prophet brings the concept to life using e-paper technology and a few other interesting gadgets, all hidden away in a picture frame.
As mentioned, the heart of this project is the e-paper display and a Teensy microcontroller. While e-paper displays are excellent for displaying static text and simple graphics, they are usually not suitable for moving images due to suffering from a form of ‘burn in’, which can leave errant pixels on the screen. This means that e-paper technology typically has a relatively low frame rate for video. [Deep Tronix] has used a custom dithering library to somewhat mitigate this issue, and the results are impressive. Moving images are loaded from an external SD card, processed, and then displayed on the e-paper display, which is almost indistinguishable from the newspaper print that surrounds it.
The seemingly magical newspaper also has a face detection feature, which is enabled by a hidden camera and the venerable ESP32 microcontroller. This system integrates with the Teensy to record and then display the reader’s face on the e-paper display. A neat trick, which is made all the more eerie when these faces are later displayed at random.
We’ve seen Daily Prophet replicas before using more traditional display technology, however the move to an e-paper display goes a long way to improving the overall aesthetics, despite the lower frame rates. With Halloween just around the corner, you might just end up tricking a few people with this clever prop – check out all the build details here.
Continue reading “Muggle Uses E-Paper For Daily Prophet Replica”
Sometimes you don’t know what you want until you see it, and that goes for keyboard designs as much as it does the dessert cart. The Railroad is [DiplomacyPunIn10Did]’s first keyboard design, believe it or not. And, well, we like what we see. Good thing it’s open-source, eh?
While we personally don’t normally go for straight-up ortholinear keyboards, this one looks split enough to be comfortable. We love that there is both an ISO Enter and a regular-sized Return, although we might put another Enter on the left side if it were our keyboard. That’s the beauty of this whole open-source keyboard thing, though. I could assign any number of those animal-capped keys to Enter. Another plus is that The Railroad uses semi-normal keycap sets, with none of this 1.25u nonsense of certain split keyboards.
All the files and the BOM are available on GitHub under a Creative Commons license. This represents JLCPCB’s max length, by the way. [DiplomacyPunIn10Did] wanted to add a num pad, but it would have made it too long. Since the pictures are so big, we put our hands up to the screen to test it out. Those innermost 1u thumb keys look like they’re placed just far enough in toward the space bars that they wouldn’t cause strain, but it’s hard to know for sure without trying a real one. (Darn you, global shortages and shipping delays!)
Yep, there are all kinds of ways to make a keyboard your own. We’ve even seen an all-wood keyboard that uses Scrabble tiles for keycaps.
Water is one of the most precious substances required to sustain human life. Unfortunately, in some areas like California, it’s starting to run out.
The ongoing drought has some people looking towards alternative solutions, such as sucking water out of the very air itself. In particular, a company called Tsunami Products has been making waves in the press with its atmospheric water generators, touting them as a solution for troubled drought-stricken areas, as reported by AP News. Today, we’ll look at how these machine capture water, and whether or not they can help in areas short on water.
Continue reading “How Practical Is Harvesting Water From The Air?”
Hackaday editors Elliot Williams and Mike Szczys flap their gums about all the great hacks of the week. Something as simple as a wheel can be totally revolutionary, as we saw with a white cane mod for the visually impaired which adds an omniwheel that knows where it’s going. We enjoyed the collection of great hacks from all over the community that went into a multi-two-liter water rocket build. You’ll hear Elliot and Mike’s great debate about the origin of comments in computer code. And we spend plenty of time joking around about the worlds longest airplane flight (it was in a tiny Cessna and lasted over two months!)
Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!
Direct download (55 MB)
Continue reading “Hackaday Podcast 142: 65 Days Of Airtime, Racecars Staring At The Ceiling, A Pushy White Cane, And Soapy Water Rockets”