Okay, perhaps the title here is a bit of an exaggeration, but this black hole lamp made by [Will Donaldson] is an interesting approach to creating a black hole simulation without destroying the earth. This lamp uses a ring of LEDs surrounding a piece of black Lycra. A motor in the lamp base pulls the Lycra, representing the distorting effect that a singularity has on space-time. It also demonstrates how black holes can (in theory) evaporate by emitting radiation, a phenomenon called Hawking radiation. It’s a simple, but effective approach that physicists have used to demonstrate gravity for some time, using stretch fabric to simulate space-time and show how gravity warps it. It’s a two-dimensional version of a three (or more) dimensional phenomenon, but it works. And, hopefully, it won’t swallow the planet and destroy us all like the real thing might.
What’s a hacker to do to profess his love for his dearest beloved? [Nitesh Kadyan] built his lady-love this awesome LED pendant – the LED BLE Hearty Necklace Badge.
The hardware is pretty vanilla by today’s hacker standards. An ATMega328p does most of the heavy lifting. An HM-11 BLE module provides connection to an Android mobile app. Two 74HC595 shift registers drive 16 columns of red LEDs and a ULN2803 sinks current from the 8 rows. The power section consists of a charger for the 320mAh LiPo and an LDO for the BLE module. All the parts are SMD with the passives mostly being 0603, including the 128 LEDs.
128 LEDs soldered wrong way around
[Nitesh] didn’t get a stencil made for his first batch of boards, so all the parts were painstakingly soldered manually and not in a reflow oven. And on his first board, he ended up soldering all of the LED’s the wrong way around. Kudos to him for his doggedness and patience.
The Arduino code on the ATmega is also quite straightforward. All characters are stored as eight bytes each in program memory and occupy 8×8 pixels on the matrix. The bytes to be displayed are stored in a buffer and the columns are left shifted fast enough for the marquee text effect. The Android app is built by modifying a demo BLE app provided by Google. The firmware, Android app, and the KiCAD design files are all hosted on his Github repository.
[Nitesh] is now building a larger batch of these badges to bring them to hillhacks – the annual hacker-con for making and hacking in the Himalayas. Scheduled for later this month, you’ll have to sign up on the mailing list for details and if you’d like to snag one of these badges. To make it more interesting, [Nitesh] has added two games to the code – Tetris and Snakes. Hopefully, this will spur others to create more games for the badge, such as Pong.
Arduino 101 is getting an LED to flash. From there you have a world of options for control, from MOSFETs to relays, solenoids and motors, all kinds of outputs. Here, we’re going to take a quick look at some inputs. While working on a recent project, I realized the variety of options in sensing something as simple as whether a light is on or off. This is a fundamental task for any system that reacts to the world; maybe a sensor that detects when the washer has finished and sends a text message, or an automated chicken coop that opens and closes with the sun, or a beam break that notifies when a sister has entered your sacred space. These are some of the tools you might use to sense light around you.
Many of you will have experimented with driving displays from your microcontroller projects, and for most people that will mean pretty simple status information for which you’d use standard libraries and not care much about their performance. If however any of you have had the need for quickly-updating graphics such as video or game content, you may have found that simpler software solutions aren’t fast enough. If you are an ESP32 user then, [Louis Beaudoin] may have some good news for you, because he has ported the SmartMatrix library to that platform. We’ve seen his demo in action, and the results as can be seen in the video below the break are certainly impressive.
In case you are wondering what the SmartMatrix library is, it’s an LED matrix library for the Teensy. [Louis]’s port can be found on GitHub, and as he was explaining to us over a beer at our Cambridge bring-a-hack, it takes extensive advantage of the ESP32’s DMA capabilities. Making microcontrollers talk with any sort of speed to a display is evidently a hot topic at the moment, [Radomir Dopieralski]’s talk at our Dublin Unconference a few weeks ago addressed the same topic.
We have to admit a soft spot for LED panels here at Hackaday, and given the ESP32’s power we look forward to writing up the expected projects that will come our way using this library.
Have you ever thought that Nixie tubes are cool but too hard to control with modern electronics? And that they’re just too expensive? [david.reid] apparently thought so and decided to create his own version of a Nixie tube, and it doesn’t get much cheaper than this.
PETG Nixie Tube
While working on a 3D printed locomotive with his son, [david.reid] used clear PETG (Polyethylene Terephthalate Glycol) 3D printer filament to move light from LEDs to various parts of the locomotive. He found this was a success, but roughed up the outside of the filament to see what would happen. Lo and behold, a warm glow appeared on the surface of the tube! Like any good hacker, his next thought was of Nixie tubes, as you have seeninmanyclocks.
His basic idea is that with a little heat you can bend the filament into any shape that you like ([david.reid] uses custom molds). You then use some sandpaper to roughen up the outside wherever you’d like light to show, and add an LED at the bottom to light it up!
Now’s a great time to get started on a project for the Hackaday Prize! If you’re looking for somewhere to start, we’d love to at least see your own take on a clock!
Electric lighting – is there anything it can’t do? Coming in all manner of forms and flavours, you can get everything from a compact reading lamp to a blindingly powerful worklight for your garage. Generally, different lights are built in different ways to suit their purpose, but it’s not the only way to do things. Enter [slisgrinder] and the MOSAIC Lighting System.
At its heart, MOSAIC is a way of building lighting rigs out of individual modules. Where it gets interesting is the design – they’re triangles! The boards carry a variety of LEDs and are laid out in a fashion that allows the power and data connections to be made between adjacent cells by laying them out next to each other. Many boards can be tesselated together to create larger, smaller, or unusually shaped arrays. The connections are well thought out, allowing the tiles to make a connection along any one of their 3 edges, regardless of orientation.
The project began out of a desire to grow okra in an otherwise inhospitable climate; to this end, there are both general work lighting modules as well as grow light versions with UV LEDs on board. The modules can be combined in different ways and command and control is done over RS-485.
It’s a tidy project that shows how a little thought can create a versatile design through the use of an unusual form factor. We’ve seen modular lighting projects before, too – like this entry to last year’s Hackaday Prize.
High-definition displays are the de facto standard today, and we’ve come to expect displays that show every pore, blemish, and bead of sweat on everything from phones to stadium-sized Jumbotrons. Despite this, low-resolution displays continue to have a nostalgic charm all their own.
Take this 32 x 16 display, dubbed PixelTimes, for instance. [Dominic Buchstaller] has gone a step beyond his previous PixelTime, a minimalist weather clock and home hub built around the same P10 RGB matrix. The previous build was a little involved, though, with a nice wood frame that took some time and skill to create.
Building your own version of PixelTimes is really approachable. The case is mostly 3D-printed, and the acrylic parts [Dominic] laser cut could just as easily be cut with a saw. And that P10 board can be source for peanuts direct from Chine. The software for the project has been upgraded since the original version, supporting flicker-free animations. Everything runs on a NodeMCU, and there are even scripts to convert your favorite GIF to an animation. Oh, and it still displays the weather too.
This looks great and seems like a lot of fun, and [Dominic] kindly provides all the files you’ll need to build your own. It shouldn’t take more than an hour to build once you’ve got all the parts.
![Courtesy of [david.reid]](https://hackaday.com/wp-content/uploads/2018/04/3837651523601540563-e1523925634762.png?w=600&h=450)
