USB LED Christmas Tree Is Making Spirits Bright

December 13, 2021 by Kristina Panos 9 Comments

[Piotr SB] knows there is no way out of the holidays; the only path is through. You’ve got to find cheer wherever and however you can, so why not cater to your own interests and build the cutest little LED Christmas tree you ever did see? And did we mention it’s USB and absolutely free (as in carols, not eggnog)?

This O-Christmas tree is made up of concentric rings that are built into a tier as you solder the LEDs. And of course you’re supposed use the LED legs as supports! One leg from each LED — 18 green and a red one for the top. Because the PCB is not quite thick enough, you’ll need to add a plastic spacer to get it to stay in the USB port. Not only is this a nice design, the snowflakes and snowman on the silkscreen totally seal the cuteness deal.

Ever get so frustrated with your Christmas tree that you want to just empty a few rounds into the thing? No? Well, you’d have a good reason to if you built this Duck Hunt ornament.

Sound-Reactive Mannequin Arms Make For Creepy Lounge Decor

December 9, 2021 by Lewin Day 8 Comments

Music visualizers were all the rage back in era of Winamp and Windows Media Player. They’re even cooler when they don’t just live on your computer screen, though, as [Emily Velasco’s] latest project demonstrates.

The build consists of two mannequin arms on a board mounted on the wall. The arms were sourced for just $5 from a Sears that went out of business, and originally fastened to the mannequin thanks to magnets inside. Thus, putting two steel plates on the board allowed the arms to be attached, and they can be freely arranged as [Emily] sees fit.

The ESP32-based Pixelblaze LED controller serves as the brains of the operation, controlling LEDs mounted inside the arms themselves. Using a dedicated controller makes working with addressable LEDs a cinch. As a further bonus, the board serves up a web interface, allowing patterns to be changed without having to hook up a cable to the device. Meanwhile, a sensor board inside the arms uses a microphone to enable the light show to react to sound and music.

It’s one of the more obscure uses for an old mannequin, but definitely one that appeals to our love of everything that flickers and glows. It’s a build very much up [Emily’s] alley; as a prolific maker, she loves to build weird and wonderful creations, as shared during her talk at the 2019 Hackaday Superconference. Video after the break.

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(Getting Rid Of) The Ghost In The LED

December 8, 2021 by Ryan Flowers 38 Comments

Multiplexing is a very old technology in which control signals are intermixed for the sake of being able to control more devices than there are control signals. For [mihai.cuciuc], the problems started when he multiplexed some very efficient LEDs.

The problem? In two banks of six LEDs each, both LEDs connected to a single Arduino pin would light, even when only one bank was turned on at the ground side. The LED In the bank that was switched on lit brightly, and its corresponding LED in the bank that was off would also be very dimly lit. [mihai] was able to determine that the problem was not due to a leaky transistor, but rather due to a quality of the LEDs themselves.

What is an LED but a diode, and it’s well known that diodes also have capacitance. In fact, this quality is exploited in varactor diodes, a specialty diode whose capacitance can be changed by varying the voltage on the cathode. [mihai] deduced that this capacitance was causing current to flow in the bank that was off. Where was the current going? From the Arduino pin that was on, through its attached LED, and then into the rest of the bank of LEDs, charging them like capacitors. [mihai] hasn’t seen this before, but theorizes that for the latest batch of high efficiency LEDs, this minute current is enough to light the LED through which the current is flowing.

[mihai]’s solution is an elegant hack which he’s made available for your perusal. You might also enjoy this introduction to diode basics by W2AEW. If you have any great diode or LED hacks of your own, be sure to drop us a line!

An Easy Music Visualizer With The Arduino Nano

December 8, 2021 by Lewin Day 3 Comments

Flashing LEDs are all well and good, but they’re even better if they can sync up with ambient sounds or music. [mircemk] has built the LUMAZOID visualizer to do just that, relying on some staple maker components to do so.

The build is open-source, and designed to work with strings of 60, 120, or 180 WS2812B LEDs. An Arduino Nano is charged with running the show, capturing audio via its analog-to-digital converter. A sensitivity pot enables the input level to be set appropriately.

From there, a Fast Fourier Transform is taken, providing data on the intensity of the audio in various frequency bins. The LUMAZOID can be set up to respond to just bass or to all frequencies as a whole. This data is then used to pulse the LEDs in time with the beat.

It’s a fun project that demonstrates the basic techniques required to build an audio-reactive visualizer. We’ve seen some other great builds in this space before, too. Video after the break.

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Two Wire Sensors On LED Strips

December 4, 2021 by Lewin Day 7 Comments

While addressable LED strips are all the rage, [Mike] from [mikeselectricstuff] has been working on an installation using the more basic two-wire strips that are simply controlled via PWM dimming. He’s recently figured out a tidy way to send sensor signals down these strips without adding any additional cabling.

Schematic for hooking up a sensor — The circuit in question.

The build uses 24 V LED tape, which consists of gangs of 6 LEDs in series with a forward voltage of 3V. Thus, these strips don’t even begin to light until approximately 18V is across them.

By adding a 15 V Zener diode and a resistor across the MOSFET which dims the LEDs, a voltage of around 9 V can be put across the LEDs without lighting them up when the MOSFET PWM dimmer is in its off phase. A PIC10F322 microcontroller and an accelerometer can then be run from this voltage, with the aid of a 3.3 V regulator wired in parallel with the LEDs. The regulator must also be able to handle the full 24 V when the LEDs are switched on.

A transistor is also wired up, switching a 2.2 K resistor in parallel with the LEDs. When turned on by the PIC, this transistor causes roughly a 10 mA current to flow through the Zener diode and its series resistor. The voltage developed across that series resistor can be measured as the transistor is turned on and off. In this case, the pulse width used to turn that transistor on is relative to motion detected by the accelerometer on the end of the LED strip.

Turning the LEDs on at 100% duty cycle prevents the system working, as the pulse widths generated by the sensor circuit can’t be detected when the LED line is held high all the time. However, in practice, it matters not — running the LEDs at a maximum 98% duty cycle eliminates the issue.

It’s an ingenious way to send sensor signals down a two-wire LED strip, even if it does take a second to wrap one’s head around it. It also seems to do a great job of adding motion-reactive effects to the LED strips in question. It’s not the first LED project we’ve seen from [Mike], either. Video after the break.

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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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The Tower, a discrete component circuit sculpture clock

A Breathtaking Circuit Sculpture Clock

November 10, 2021 by Dan Maloney 8 Comments

Here at Hackaday, we pride ourselves on bringing you the very freshest of hacks. But that doesn’t mean we catch all the good stuff the first time around, and occasionally we get a tip on an older project that really should have been covered the first time around. This remarkable circuit sculpture clock is a perfect example of one that almost got away.

[Gislain Benoit] creation is called “The Tower” for good reason: it’s built inside what amounts to a giant glass test tube. Inverted and adorned with MDF discs, the Pyrex tube stands 5 feet (1.5 meters) tall, and is absolutely stuffed with electronic goodness. There are more than 2,100 discrete components mounted inside on a helical framework of carefully bent wires, forming a vertical sculpture that displays the time on three separate pairs of seven-segment displays. All the diode-transitor logic circuits are built from discrete components; nary a chip was used, and to spice things up, [Gislain] used LEDs in place of regular diodes everywhere in the circuit. The result is a constant light show as the clock goes through its paces.

The whole thing looks amazing, and even the power supply at the base works in the overall presentation. The design is a bit of a departure from [Gislain]’s previous circuit sculpture clock, but it’s just as beautiful, and equally as mind-boggling in terms of construction difficulty.

Thanks to [Maarten] for the belated tip on this one.