Back To The Future We Go With This Flux Capacitor PCB Badge

December 5, 2021 by Orlando Hoilett 8 Comments

[Arnov] is a huge fan of the Back to the Future franchise, so he wanted some memorabilia from the movie to decorate his work area. Official memorabilia from successful movie franchises can be pretty expensive, so [Arnov] opted to make something himself instead, creating his own flux capacitor PCB badge.

Fortunately, [Arnov’s] design isn’t as complicated as Doc’s was from the movie (pictured on the right), so it should be a lot easier to replicate. We have a simple LED circuit driven by an 8205S MOSFET and controlled by an ATtiny microcontroller. There’s a small diode for auto-switching between USB and battery power as well as a few current limiting resistors for the LEDs. Fortunately, [Arnov’s] project only requires 0.017 W to power, so no plutonium nuclear reactor is necessary and you can easily power it with a standard coin cell battery or with a USB. That’s quite a relief.

As with many of [Arnov’s] projects, the beauty in its design lies in the detail he places on the PCB layout. In this case, the layout is a bit easier than some of his other work needing only to arrange the blinking LEDs in a “Y” shape to mirror the flux capacitor seen in the movies. He also adds a bit of detail to the silkscreen to help complete the aesthetic.

We think this is worth adding to your PCB badge collection.

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A scrolling name badge that uses LED matrices.

Scrolling Name Badge Is Sure To Break The Ice

November 29, 2021 by Kristina Panos 2 Comments

Most makerspaces and hackerspaces have one night per week or month where the ‘space is open to the public in order to entice new people into joining up. Whereas most members just write their name in Sharpie on a piece of masking tape, [Madison] wanted to do something extra. And what better way to get people interested in your ‘space than by wearing something useful that came out of it?

The badge runs on an ATtiny45 and uses three 8×8 ultra-bright LED matrices for scrolling [Madison]’s name. It’s powered by a tiny LiPo battery that is boosted to 5 V. This build really shows off a number of skills, especially design. We love the look of this badge, from the pink silkscreen to the the typography. One of the hardest things about design is finding fonts that work well together, and we think [Madison] chose wisely. Be sure to check it out in action after the break.

Custom name badges are a great way to start conversations no matter where you go. Here’s one that uses EL wire and LEDs that light up in sequence for an animated effect.

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Wireless LEDs Aren’t Really Magic

November 29, 2021 by Al Williams 18 Comments

[Atomic14] bought some wireless LEDs that receive power from a base station. They were very neatly packaged, but — we like it — he took one apart and made his own versions. They may not look as polished, but they work and they are undeniably cool.

The LEDs work by receiving power from an induction coil. Once you have power, lighting up an LED is no big deal. Reverse engineering found the transmitter sends 217 kHz into a 2.2 mH inductor. A capacitor resonates the coil and drives the attached LED.

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Own The Night With This Ludicrously Bright DIY Flashlight

November 8, 2021 by Dan Maloney 27 Comments

If you’re a flashlight person, you know that there’s little you would do to get the brightest, most powerful, most ridiculous flashlight possible. You might even decide to build yourself a ludicrously powerful flashlight, like [Maciej Nowak] did.

If you choose the DIY route, be warned that it’s probably not going to be a simple process, at least if you follow [Maciej]’s lead. His flashlight is machined out of aluminum rounds, all turned down on the lathe to form the head of the flashlight. The head is made from three parts, each of which acts as a heat sink for the five 20-Watt CREE XHP70 LED modules. The LEDs are mounted with care to thermal considerations, and wired in series to DC-DC converter that provides the necessary 30 V using a battery pack made from four 21700 Li-ion cells. The electronics, which also includes a BMS for charging the battery and a MOSFET switching module, form a tidy package that fits into the aluminum handle.

The video below shows that the flashlight is remarkably bright, with a nice, even field with no hotspots. Given the 45-minute useful life and the three-hour recharge time, it might have been nice to make it so anywhere from one to five of the LEDs could be turned on at once. Some interesting effects might be had from switching the LEDs on sequentially, too.

Given the proclivities of our community, it’s no surprise that this is hardly the first powerful flashlight we’ve seen. This one broke the 100-Watt barrier with a single COB LED, while this ammo-can version sports an even higher light output. Neither of them looks much like a traditional flashlight, though, which is where [Maciej]’s build has the edge.

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Big RGB LED Cube You Can Build Too

November 4, 2021 by Dave Rowntree 35 Comments

LED cubes are really nothing new, many of us consider the building of a good sized one almost an electronics rite of passage that not so many manage to find the time or have the skill to pull off. It’s our pleasure to draw your attention to a lovely build, showing all the processes involved, the problems and the solutions found along the way.

Building a small cube is somewhat of a trivial affair, especially without considering PWM colour mixing, however as simple maths will illustrate, as you increase the number of LEDs on each side, the total number will quickly get quite large. More LEDs need more power and increase control complexity considerably. A larger matrix like this 16 x 16 x 16 LED build, has a total of 4096. This would be a nightmare to drive with plain RGB LEDs, even with cunning multiplexing, but luckily you can buy indexable LEDs in a through-hole package similar to the ubiquitous WS2812-based SMT LEDs you see around. These are based on the PD9823 controller, which can be programmed as if they were a WS2812, at least according to this analysis. Now you can simply chain a column of LEDs, with the control signal passed from LED to nearest neighbour.

Early on in the video build log, you will note there are four power supply modules needed to feed this juice. If we assume each LED consumes 60 mA on full-white (the data for this product link shows a peak value of 100 mA) that is still a total of 246 A or around 1 kW of power. The video does shows a peak power measurement of around this figure, for the whole array on full white, so the maths seems about right.

Control is via a Teensy 4.0 using the FlexIO function of the IMXRT1060RM CPU, and a bunch of 74AHCT595 shift registers giving 32 channels of up to 1000 LEDs per channel if needed. Roughly speaking, using the DMA with FlexIO, the Teensy can drive up to 1 Million LED updates per second, which works out about 32 channels of 100 LEDs per channel updated at 330 frames/sec, so plenty of resource is available. All this is with almost no CPU intervention, freeing that up for handling the 2.4-inch LCD based UI and running the animations, which looks pretty darn slick if you ask us. You can checkout the description of the firmware in the firmware section of the GitHub project. 3D printed jigs allowed for bending and clipping the LEDs leads as well as fixing and aligning the LED column units, so there really is enough detail there to allow anyone so inclined reproduce this, so long as you can swallow the cost of all those LEDs.

For a different approach to LED cubes, checkout this sweet panel based approach, and here’s a really small 4x4x4 module for those with less space to spare.

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Sign Detects RF To Show You Are On The Air

October 19, 2021 by Al Williams 2 Comments

Like a lot of hams, [Stuart] wanted an “on the air” sign. These signs often connect to a PTT switch or maybe an output from the transmitter that also does things like switches antennas or switches in an amplifier. [Stuart’s] version, though, simply senses the radio frequency emissions from the transmitter and lights up that way. You can see two videos about the sign, below.

Honestly, we are a little worried that he might have too much RF at his operating position. Presumably, the device is pretty sensitive, especially if there’s any actual antenna on the sign. A comparator and a pot let you set the sensitivity so it doesn’t light up when your garage door opens.

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Learn DMX512 Basics

October 15, 2021 by Al Williams 11 Comments

If you’ve done anything with modern lighting effects, you’ve probably heard of DMX, also known as DMX512. Ever wonder what’s really happening under the hood? If so, then you should have a look at [EEForEveryone’s] video on the topic, which you can see below.

At the core, the DMX512 uses RS485, but adds software layers and features. The video uses the OSI model to show how the system works.

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