Interactive Core Memory Shield Helps Explains The Past

December 19, 2019 by Gerrit Coetzee 9 Comments

[Andy Geppert] sends in his incredibly clever interactive core memory shield.

In a great display of one hacker’s work being the base for another’s, [Andy] started out with [Jussi Kilpelainen]’s core memory shield for Arduino. As he was playing with the shield he had a desire to “see” the core memory flipping and got the idea to add an LED matrix aligned behind the individual cores.

The first iteration worked, but it only showed the state that the Arduino believed the core memory to be in. What he really wanted was a live read on the actual state. He realized that an Adafruit Featherwing 8×8 matrix display also fits behind the core memory. Now the LEDs update based on the read state of the core memory. This allows him to flip the individual bits with a magnetic stylus and see the result. Very cool.

You can see a video of it working after the break.

Continue reading “Interactive Core Memory Shield Helps Explains The Past” →

A LED Cube Designed For Easy Assembly

December 15, 2019 by Gerrit Coetzee 6 Comments

LED cubes are mesmerizing and fun, but they’re usually a pain to build. Not so with [burkethos]’s cleanly designed cube.

Many cubes are put together in an elaborate sculptural style. Traditionally the leads of the LEDs are artistically bent and then hours are spent laboring over the future rainbow Borg cube. This build is more reminiscent of a motherboard or back plane design. The LEDs are surface mount units re-flowed onto a rake shaped PCB. At the base of each “rake” there’s a right angle male header. This is then soldered to base board which creates a reliable mechanical bond.

There are some downsides to this approach. For example, the PCBs occlude the LEDs at some viewing angles. However, this can be mitigated with careful placement in the room, or in one variation, mounting the cube at a different orientation so the rakes are horizontal rather than vertical.

Regardless, we appreciate this new take on an old project and can definitely see it having a more universal appeal than the kits that require a couple weeks of afternoons to finish.

Supercon SMD Challenge Gets 3D Printed Probes: Build Your Own

December 12, 2019 by Al Williams 2 Comments

This year was the second SMD challenge at Supercon, so it stands to reason we probably learned a few things from last year. If you aren’t familiar with the challenge, you are served some pretty conventional tools and have to solder a board with LEDs getting progressively smaller until you get to 0201 components. Those are challenging even with proper tools, but a surprising number of people have managed to build them even using the clunky, large irons we provide.

During the first challenge, we did find one problem though. The LEDs are all marked for polarity. However, since we don’t provide super high power magnification, it was often difficult to determine the polarity, especially on the smaller parts. Last year, [xBeau] produced some quick LED testers to help overcome this problem. This year we refined them a bit.

As you can see, the 2018 model was a very clever use of what was on hand. A CR2032 holder powered the probes and the probes themselves were two resistors. If you can get the LED to light with the probes you know which lead is the anode and which is the cathode. A little red ink makes it even more obvious. Continue reading “Supercon SMD Challenge Gets 3D Printed Probes: Build Your Own” →

A Tree Of LEDs That Blows Out Like A Candle

December 11, 2019 by Donald Papp 14 Comments

The beautiful workmanship in [Andrew]’s LED tree is gorgeous all on its own, but of course there’s more going on than meets the eye. This LED tree can be blown out like a candle and it even playfully challenges a user to blow out all the lights at once in a single breath.

Some of you may remember the fascinating example of an LED you can blow out like a candle which had the trick of using the LED itself as a sensor. Like any diode, the voltage drop across the LED changes very slightly based on temperature. By minimizing thermal mass with surface-mount LEDs and whisker-thin wires, it was possible to detect when the LED was being blown on.

The LED tree shown here uses the same basic principle, but with a few important changes. The electronics have been redesigned and improved, and the Arduino used in the original proof of concept is ditched for stacked custom PCBs. Each board has a diameter under 100 mm in order to take advantage of the fab house’s lower cost for small boards. [Andrew] says that while the boards required a lot of time-consuming hand soldering and assembly, the payoff was that five boards rang in at barely five dollars (plus shipping) and that’s hard to beat.

Watch the tree in action in the brief video embedded below.

Continue reading “A Tree Of LEDs That Blows Out Like A Candle” →

LED Matrix Watch Is The Smart Watch We Didn’t Know We Wanted

December 4, 2019 by Gerrit Coetzee 17 Comments

[Mile] put together this stunning LED matrix watch, on which the stars of this show are the 256 monochrome 0603 LEDs arranged in a grid on its face. The matrix is only 1.4in in the diagonal and is driven by a combination of an LED driver and some shift registers. The brain is an ATmega328p. We appreciate the extra effort taken to add a USB to UART adapter so the mega can be programmed over USB. It also contains all the necessary circuitry to charge and maintain the lithium battery inside safely.

Input into the device is done with a hall effect sensor which keeps the build from having any moving parts. The body is a combination of 3D printed parts and really fetching brass details connecting to the band.

If it weren’t over the top enough the build even has an ambient light sensor so the display can dim or brighten depending. We bet [Mile] is pretty proud to wear this on their wrist.

Winter Is Coming, This Clock Will Let You Know When

December 2, 2019 by Tom Nardi 1 Comment

For Game of Thrones fans, it’s an awkward time. The show has ended its run on HBO (not without a certain level of controversy), the planned prequel is still years away, and who knows when George R. R. Martin will actually get around to writing the final books in the series. Fans have no choice but to entertain themselves while waiting for further tales of adventure from Westeros, which is how we get things like this motorized clock from [Techarge].

Inspired by the now iconic opening sequence from the HBO series, elements of the 3D printed model spin around while the theme song is played courtesy of a DFPlayer Mini MP3 player module and small 2 watt speaker. The audio hardware, motor, and four digit LED display module in the front are all connected to an Arduino with a custom PCB shield, giving the inside of the clock a very clean and professional appearance.

Around the back side [Techarge] has two small push buttons to set the hour and minutes, and a large toggle to control the music and movement. As of right now it needs to be switched on and off manually, but a future enhancement could see it kick on hourly. We’d also like to see an RTC module added to the PCB, or better yet, switch over to the ESP8266 and just pull the time down from NTP.

Who knows? By the time you’ve built one of these clocks for yourself, and the hand-made Iron Throne phone charger stand to go with it, maybe ol’ George will have slipped out a new book. But don’t count on it.

Making Your Own Caving Headlamp

December 2, 2019 by Sharon Lin 15 Comments

An important distinction between equipment used for caving, climbing, biking, and other outdoor activities is the level of stress that’s generally applied. For instance, while climbing helmets are built to withstand the impact of sharp rocks, they’re not made to protect a biker’s head from suddenly hitting the ground. Likewise, while camping headlamps may be able to survive a light rainfall, they’re probably not made to shine at the 800 lumens after being submerged underwater.

[LukeM] built himself a caving headlight, after being “fed up with what was available on the market”. While his project is a bit older, it’s still pretty helpful for any newer hobbyists looking to try their hand at building a custom headlamp. Many cavers have to carry around a few primary – one main light for general visibility and a secondary light for focusing on specific objects. These are typically worn on the helmet, attached somehow to prevent the light source from falling off mid-climb. From tricky operations, varying distances, cost, and ease of battery replacement, there are a number of reasons why a caver might want to build their own customizable head lamp.

The result is rugged, waterproof, reliable, bright enough to supplement flashes in caving photos and also dim enough for general use (30-700 lumens). It has options for wide and narrow beams, displays a neutral to warm color, and is relatively upgradeable without too much trouble. At the same time, it’s also fairly compact, with all of the components packed inside of a short section of 3″x2″ aluminum tubing, protected at the back and front by aluminum and acrylic backings. The LEDs used are four Cree XP-E R2 bin LEDs and a hipFlex driver from TaskLED with programmable settings for max output, thermal protection temperature, warning voltage, and lighting modes. I’m personally already smitten with the level of customizability of this build.

On top of all of that, it’s been cave tested and approved!