Daisy Chained Seven Segment Art Display

October 23, 2019 by Sharon Lin 8 Comments

This seven segment art display makes use of a 81 seven segment red common cathode LED displays. The LEDs are arranged onto 100x100mm boards that each contain an Arduino Nano and 9 seven segment displays, daisy chained through three-pin headers located on the sides of the boards. The pins (power, ground, and serial) provide the signals necessary for propagating a program across each of the connected boards.

The first board – with two Arduino Nanos – sends instructions for which digits to light and drives the display, sending the instructions over to the next board on the chain.

In a multiplexed arrangement, a single Arduino Nano is able to drive up to 12 seven segment displays, but only 9 needed to be driven for the program, keeping D13’s built in LED and the serial pins free. Since no resistors are featured on the boards, current limiting is done through software. This was inspired by the Bubble LED displays on the Sinclair Scientific Calculator, and was done in order to achieve a greater brightness by controlling the current through the duty cycle.

The time between digits lighting up is 2ms, giving them some time to cool down. The animations in the demos featured falling and incrementing digits, as well as a random number generator using a linear feedback shift register.

Continue reading “Daisy Chained Seven Segment Art Display” →

Hacking The IKEA TRÅDFRI LED Power Supply

October 8, 2019 by Donald Papp 22 Comments

Just because something is being actively documented and tampered with by enthusiastic hackers doesn’t mean the information is handily centralized. There can be a lot of value in gathering disparate resources in one place, and that’s exactly what [Trammell Hudson] has done with his resource page for hacking the IKEA TRÅDFRI LED power supply with wireless interface. Schematic teardown, custom firmware images, it’s all there in one convenient spot.

Back in 2017, the IKEA TRÅDFRI hacking scene was centered around the LED light bulbs but as the group of products expanded, the rest of the offerings have also gotten some attention.

Why bother tampering with these units? One reason is to add features, but another is to make them communicate over your own MQTT network. And MQTT is the reason you are only a Raspberry Pi and a trip to IKEA away from the beginnings of a smart home that is under no one’s control or influence but your own.

This Word Clock Has Dirty Alphanumeric Mouth

September 29, 2019 by Tom Nardi 7 Comments

Clocks which use words to tell the time in place of numbers are an increasingly popular hacker project, but we have to admit that before seeing this gorgeous clock from [Mitch Feig], we didn’t realize how badly we wanted to see one that could curse like a sailor.

But don’t worry, the WordClock-1 knows more than just the bad words. Rather than using an array of illuminated letters as we’ve seen in previous clocks, this one uses six alphanumeric LED displays. So not only can it display the time expressed with words and numbers, but it can show pretty much any other text you might have in mind.

[Mitch] is partial to having his clock toss a swear word on the display every few seconds, but perhaps you’d rather have it show some Klingon vocabulary to help you brush up. The lack of extended characters does limit its language capabilities somewhat, but it still manages to include Spanish, Italian, French, and Croatian libraries.

The ESP32 powered clock comes as a kit, and [Mitch] has provided some very thorough documentation that should make assembling it fairly straightforward as long as you don’t mind tackling a few SMD components. Additional word databases are stored on an SD card, and you can easily add your own or edit the existing ones with nothing more exotic than a text editor. The clock itself is configured via a web interface, and includes features like RGB LED effects and support for pulling the time down from an external GPS receiver.

Of course, if you’re content with what we can apparently now refer to as “old style” word clocks, we’ve seen plenty of projects which should serve as inspiration for anyone looking to roll their own textual timepiece.

Continue reading “This Word Clock Has Dirty Alphanumeric Mouth” →

LEDs Light The Way To This Backdoor

September 27, 2019 by Jenny List 41 Comments

A curious trend for some years in the world of PC hardware has been that of attaching LEDs to all the constituent parts of a computer. The idea is that somehow a gaming rig that looks badass will somehow be just a little bit faster. As [Graham Sutherland] discovered when he wanted to extinguish the LEDs on his new Gigabyte graphics card, these LEDs can present an unexpected security hazard.

The key to their insecurity comes in the Gigabyte driver. This is a piece of software that you would normally expect to be an abstraction layer with an interface visible to your user level privilege, and a safe decoupling between that and the considerably more security sensitive hardware layer from which the LED bus can be found. Instead of this, the Gigabyte driver is more of a wrapper that simply exposes the LED bus directly to the user level. It’s intended that user-level code can easily bit-bang WS2812 LEDs without hinderance, but its effect is to provide a gaping hole in the security layers intended to keep malicious code away from the hardware. The cherry on the cake is provided by the discovery of a PIC microcontroller on the bus which can be flashed with new code, providing an attacker with persistent storage unbeknownst to the operating system or CPU.

The entire Twitter thread is very much worth reading whether you are a PC infosec savant or a dilettante, because not only should we all know something about the mechanisms of PC backdoors we should also be aware that sometimes a component as innocuous as an LED can be a source of a security issue.

Thanks [Slurm] for the tip.

Gigabyte motherboard picture: Gani01 [Public domain].

Control Lighting Effects Without Programming

September 22, 2019 by Bryan Cockfield 12 Comments

Working in a theater or night club often requires a specialized set of technical skills that you might not instantly think about. Sure, the audio system needs to be set up and managed but the lighting system is often actively managed as well. For simple setups, this is usually not too difficult to learn. With more complicated systems you will need to get elbow-deep into some software. With [trackme518]’s latest tool, though, you will only need to be able to edit video.

Sure, this sounds like just trading one piece of software for another, but it’s more likely that professionals working in lighting will already know how to edit video rather than know programming or complicated proprietary lighting software. All you have to do to control a set of lights is to create a video, or use an existing one, and the lighting system will mimic the video on its own. If you do know programming, though, it’s written in Processing Java so changes aren’t too difficult to make.

The software (available on the project’s GitHub page) will also work outside of a professional environment, as well. It’s set up to work with DMX systems as well as LED strips so you could use it to run a large LED display board using only an input video as control. You could even use it to run the display on your guitar.

Photo courtesy of Rob Sinclair (Gribiche) [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]

Glitching LED Display Proves Crowd Favorite

September 17, 2019 by Lewin Day 9 Comments

There’s something enchanting about the soft glow of a properly diffused LED, and this is only improved by greater numbers of LEDs. [Manoj Nathwani] was well aware of this, setting out to build a large display using ping-pong balls for their desirable optical qualities.Unfortunately, not everything went to plan, but sometimes that’s not all bad.

The matrix, built back in 2016 for EMF Camp, was sized at 32×18 elements, for a total of 576 pixels. This was achieved with the use of 12 WS2811 LED strips, with the lights set out on a 50mm grid. Cheap knock-off pingpong balls were used for their low cost, and they proved to be excellent diffusers for the LEDs.

With everything wired up to a NodeMCU, basic testing showed the system to be functioning well. However, once the full matrix was assembled in the field, things started to fall over. Basic commands would work for the first 200 LEDs or so, and then the entire matrix would begin to glitch out and display random colors. Unable to fix the problem in the field, [Manoj] elected to simply run the display as-is. Despite the problems, passers-by found the random animations to be rather beautiful anyway, particularly at night.

After the event, [Manoj] determined the issue was due to the excessive length of the data line, which in the final build was 48 meters long. While the problem may be rectified when [Manoj] revisits the project, the audience seemed to appreciate the first revision anyway.

LED displays will be a hacker staple until the heat death of the universe. Ping pong balls will also likely retain their position as a favorite diffuser. If you’ve got a great LED build of your very own, be sure to hit up the tips line!

Stack Those Boards For An Extra-Special Backlit LED Effect

September 14, 2019 by Jenny List 6 Comments

By now most of us should be used to backlit LEDs, in which a bare board with no copper or soldermask as an LED mounted on its reverse side to shine through as if with a diffuser. [Wim Van Gool] has created such an LED display with a twist, instead of reverse mounted LEDs his Shitty Add-On for Area3001 hackerspace in Leuven, Belgium has a set of WS2812 addressable LEDs shining upwards through a void in a stack of PCBs to the diffuser. The effect is of something that looks about the size and shape of a Kit-Kat finger with a glowing hackerspace logo on the front, and it breaks away from the SAO norm.

Full details are on the GitHub repository for the project, in which we find both large and small takes on the same idea. It appears that there is no onboard processor and that the WS2812s are driven from the host badge, but that doesn’t take away from the ingenuity of the design.

The through-PCB diffuser seems to be the badge must-have of the moment, we’ve seen quite a few such as the recent Numberwang badge. That’s the exciting thing about badge design though, one always knows that there will be a new twist along in the next crop of badges, to keep everything fresh.