A two picture montage of a boy wearing a sonic the hedgehog costume with LEDs in them. The left picture is at night with the boy wearing sunglasses and a face mask with the sonic costume head piece lit up. The right picture is during the day with the boy wearing a face mask, holding a plastic pu mpkin bucket for candy and wearing a lit up sonic the hedgehog costume in the front yard of a house.

LEDs Put New Spin On A Sonic The Hedgehog Costume

November 26, 2022 by Abe Connelly 1 Comment

[Wentworthm] couldn’t say no to his son’s plea for a Sonic the Hedgehog costume for Halloween but also couldn’t resist sprucing it up with LEDs either. The end result is a surprisingly cool light up Sonic the Hedgehog costume.

After some experimentation, [Wentworthm] ordered two costumes and ended up mixing and matching the head piece of one with the body suit of the other. For the head, [Wentworthm] created six 3D printed “quills” that had slots for the WS2812B LED strips to slide into and diffuse out the sides, with each quill sliding into the folds of the Sonic head “spikes”. Sewn strips of cloth were used to house the LED strips that were placed down the sides of the costume. An additional 3D printed switch housing was created to allow for a more robust interface to the two push buttons to activate the LEDs. An Arduino Nano, soldered to a protoboard, was used to drive the LED strips with a USB battery pack powering the whole project.

[Wentworthm] goes into more detail about the trials and errors, so the post is definitely worth checking out for more detail on the build. Halloween is always a great source of cool costumes and we’ve featured some great ones before, like a light up crosswalk costume to making a giant Gameboy colour costume.

Video after the break!

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Homebrew LED Bulbs Keep Your Circadian Rhythms Steady

November 24, 2022 by Dan Maloney 18 Comments

There was a time when LED light bulbs were a premium product that commanded a premium price, mainly because of limited supply and the usual marketing tricks. But now is not that time, since you can pick up an LED bulb for a buck or two at pretty much any store. So why in the world would you go to the effort to make your own light bulb?

For [DiodeGoneWild], the answer is simple: it’s all about staying in rhythm. Circadian rhythm, that is. We all know how light toward the blue end of the spectrum is bad for our sleep cycle, since it convinces our lizard brain that dawn is at hand. But even if you pick an LED bulb with a warm, or reddish, color temperature, there’s still a lot of UV light being emitted thanks to the phosphor LEDs that are typically used in them.

[DiodeGoneWild]’s first attempt at a design, in the first video below, mostly avoids phosphor LEDs in favor of a mix of yellow, red, and yellow-green LEDs to get a warmer spectrum. He used the housing and base from an expired bulb to enclose his custom circular PCB, the fabrication of which using a hand drill as a lathe and a Dremel to machine concentric tracks in the cladding was a real treat. So was the power supply, for that matter — a dropping capacitor followed by a bridge rectifier and a filtering cap. We like the discharge resistors across the caps and the fusible resistor on the mains side — it’s nice to see safety factored in from the start. And what’s not to like about using a DVD as a makeshift spectroscope?

We see that [DiodeGoneWild] has just dropped a second design, this time in a much smaller bulb and with relatively more phosphor LEDs.

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Tidy POV Display Using The ESP32

November 23, 2022 by Dave Rowntree 9 Comments

Chinese Youtuber [corebb] presents the second version of his POV display. The earlier version used 5050-sized SMT addressable LEDs, which didn’t give great resolution, so he rev’d the design to use a much higher number (160 to be exact) of APA102 LEDs. These are 2mm on the side, making them a little more difficult to handle, so after some initial solder paste wobbles, he decided to use a contract assembly house to do the tricky bit for him. This failed as they didn’t ‘understand’ the part and placed them the wrong way around! Not to be deterred, he had another go with a modified solder stencil, and eventually got the full strip to light up correctly.

Based on an ESP32 (using the Arduino stack) and SDCard for control, and a LiPo cell charged wirelessly, the build is rather tidy. A couple of hall effect switches are mounted at the start of each of the two arms, presumably lining

up with a magnet on the case somewhere, although this isn’t clear. The schematic and PCB appear to have been designed with JLCEDA, which is a repackaging of EasyEDA. We can see the attraction with the heavy integration of this with the JLC and LCSC services. It appears that he even managed to get streamed video working — showing a live video from a webcam — which is quite an undertaking to pull off when you think how much processing needs to happen in real-time. As he alludes to in the video, trying to increase the resolution beyond this point is not viable with the processing capability of the ESP32.

A resin-printed case finishes off the build, with a screw-thread mount added to the rear, to allow typical camera mounts to be used to hold the thing down. A smart move we think.

We love POV displays around here, this spherical POV display is especially fabulous, but you don’t need fancy hardware if you have a handy ceiling fan and a bit of protoboard spare.

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Surface Mount Breathing Light PCB, using LM358 op-amp

Surface-Mount Light Breathes Life Into Your Project

November 11, 2022 by Dave Walker 13 Comments

If you’ve ever seen those gadgets with the “breathing light” LEDs on them and wondered how to do it, then [DIY GUY Chris] can show you how to design your own surface-mount version, using only analogue electronics.

Simulation trace showing the LED breathing light circuit operating. Traces for voltage and current are shown over a few seconds — The LED current tracks up and down in an approximately triangular-wave pattern

The circuit itself is built around a slow triangular-wave oscillator, that ramps the current up and down in the LEDs to make it look as if the lights are breathing in and out. The overall effect is rather pleasing, and the oscillation speed can be adjusted using the on-board potentiometer.

This project is actually an update to a previous version that used through-hole components (also shown in the video below), and goes to show that revisiting completed projects can give them a new lease of life. It also shows how easy it has become to design and order custom circuit boards these days. It’s not so long ago that a project like this would have been either made on stripboard or etched from copper-plated FR4 in a bubbling tank of acid!

If you have revisited an old project that you’re proud of and would like to show others, why not drop us a message on our tips line?

We have covered some other options for breathing LEDs in the past, such as this digital logic version, and this Arduino library that has a host of other effects to choose from, too. Continue reading “Surface-Mount Light Breathes Life Into Your Project” →

"The Great Resistor" color code illumination project

The Great Resistor Embiggens The Smallest Value

November 5, 2022 by Dave Walker 29 Comments

With surface-mount components quickly becoming the norm, even for homebrew hardware, the resistor color-code can sometimes feel a bit old-hat. However, anybody who has ever tried to identify a random through-hole resistor from a pile of assorted values will know that it’s still a handy skill to have up your sleeve. With this in mind, [j] decided to super-size the color-code with “The Great Resistor”.

Resistor color code from Wikipedia with white background — How the resistor color-code bands work

At the heart of the project is an Arduino Nano clone and a potential divider that measures the resistance of the test resistor against a known fixed value. Using the 16-bit ADC, the range of measurable values is theoretically 0 Ω to 15 MΩ, but there are some remaining issues with electrical noise that currently limit the practical range to between 100 Ω and 2 MΩ.

[j] is measuring the supply voltage to help counteract the noise, but intends to move to an oversampling/averaging method to improve the results in the next iteration.

The measured value is shown on the OLED display at the front, and in resistor color-code on an enormous symbolic resistor lit by WS2812 RGB LEDs behind.

Inside view of the great resistor showing WS2812 LEDs and baffle plates — Inside The Great Resistor, the LEDs and baffle plates make the magic work

Precision aside, the project looks very impressive and we like the way the giant resistor has been constructed. It would look great at a science show or a demonstration. We’re sure that the noise issues can be ironed out, and we’d encourage any readers with experience in this area to offer [j] some tips in the comments below. There’s a video after the break of The Great Resistor being put through its paces!

If you want to know more about the history of the resistor color code bands, then we have you covered. Alternatively, how about reading the color code directly with computer vision?

Continue reading “The Great Resistor Embiggens The Smallest Value” →

Screenshot from the video showing comparisons between diffused light pictures at different brightnesses and diffusers applied

LED Diffusers Confusing? Organize A Practical Contest

November 3, 2022 by Arya Voronova 8 Comments

We all want a nice and shiny LED strip that doesn’t actually look like it consists of individual LEDs – a bar of uniform light is just that much more attractive. There’s all kinds of diffusion options available out there, but they can be confusing – sometimes you’d just like to know, which one is better? If there’s one thing that could easily settle this, it’s a practical test, and that’s what [The Hook Up] has devised for us to learn from.

First off, he talks about LED strips available – between 30, 60 and 144 LED per meter variations, the latter is going to be easier to diffuse than the former. From there, there’s a few different kinds of diffuser covers and aluminum profiles you can get, and [The Hook Up] pairs them in combinations, filming them from a distance and giving us concise visuals of how each combination works at different duty cycles, as well as making brightness measurements every now and then to evaluate losses of different diffuser layers. He proposes a simple rule – when picking a diffuser, distance between the LEDs and the diffuser has to be larger than the between-LED distance, and experiments confirm that. In the end, one of the takeaways is that the differences between 60LED/m and 144LED/m strips are not significant enough that they can’t be compensated for with a decent diffuser.

Continue reading “LED Diffusers Confusing? Organize A Practical Contest” →

A segmented lamp made of circular slices of plywood. They are arranged as shutters around a long, skinny LED bulb in the center that gives off an incadescent-looking glow. A cord trails off to the left against the grey background.

Plywood Lamp Has Customizable Light Output

November 1, 2022 by Navarre Bartz 2 Comments

There’s something about light fixtures that attracts makers like moths to a flame. [danthemakerman] wanted something with a more configurable light output and built this Sculptural and Customizable Plywood Lamp.

In his detailed build log, [danthemakerman] describes how he wanted something “sort of like an analog dimmable light.” By using a stack of split plywood donuts hinged on a brass rod, he can vary the output and shape of the lamp. These shutters allow the lamp to go from bright to nightlight without using any electrical dimming components.

The plywood was rough cut on a bandsaw before being turned on a lathe. The light cover sections were then hollowed out with a Forstner bit and split in half. The tricky bit is the overlap of the cut on the hinge side of the shutters. Cutting the piece exactly in half would’ve required a lot more hardware to make this lamp work than what was achieved by patient woodworking.

If you’d like to see more ways to make light fixtures with plywood, check out this Hexagonal Lamp, these Upcycled Plywood and Glass Lamps, or this Laser-cut Sphere Lampshade that Packs Flat.