"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?

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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.

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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.

Lighting Up Glue Stick Bicycle Tyres With RGB

October 31, 2022 by Danie Conradie 28 Comments

Being visible to motorists is a constant concern for cyclists, but we doubt [The Q] will have this problem with his RGB LED illuminated tires made from glue sticks.

The project started with a set of 3D-printed tire molds that bolt to the standard wheels. A bot of melted glue sticks is poured into the mold, allowed to cool, and the mold sections are removed with the help of a heat gun after cooling. We doubt the weight and hardness make the tires particularly practical, but you can’t make normal tires glow from the inside.

The idea to illuminate the tires probably came after molding, because they had to be cut off to fit the LEDs. [The Q] built a simple hot wire jig with a piece of nichrome wire between two screws and used it to cut a few millimeters from the inside of the tire and fit a sleeved RGB LED strip in the wheel. Power come from a set of three 18650 batteries housed with a wireless controller in a 3D printed hub-mounted enclosure.

Like [The Q]’s hubless and partial wheel bicycles, it’s a definite head-turner, with function following form.

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A prosthetic eye anodized green around the edges with a yellow and blue "iris" surrounding an LED center.

Skull Lamp Illuminates The Cyberpunk Future

October 26, 2022 by Navarre Bartz 11 Comments

Cyberpunk is full of characters with cool body mods, and [bsmachinist] has made a prosthetic eye flashlight (TikTok) that is both useful and looks futuristic. [via Reddit]

[bsmachinist] has been machining titanium prosthetic eyes for over five years now, and this latest iteration, the Skull Lamp, has a high brightness LED that he says is great for reading books at night as well as any other task you might have for a headlamp. Battery life is reported as being 20 hours, and the device is switched by passing a magnet (Instagram) near the prosthetic.

We love seeing how prosthetics have advanced in the last few years with the proliferation of advanced tools for makers. Some other interesting prosthetics we’ve covered are this DIY Socket for Prosthetics with a built-in charger and power supply and several different prosthetic projects for kids including these Heroic Prosthetics by Open Bionics, the E-Nable Alliance, and a Kid Who Designed his Own Prosthetic.

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A diagram showing an LED on the left, a lever-style plumbing valve in the center, and an Arduino Uno on the right.

Plumbing Valves As Heavy Duty Analog Inputs

October 24, 2022 by Navarre Bartz 36 Comments

Input devices that can handle rough and tumble environments aren’t nearly as varied as their more fragile siblings. [Alastair Aitchison] has devised a brilliant way of detecting inputs from plumbing valves that opens up another option. (YouTube) [via Arduino Blog]

While [Aitchison] could’ve run the plumbing valves with water inside and detected flow, he decided the more elegant solution would be to use photosensors and an LED to simplify the system. This avoids the added cost of a pump and flow sensors as well as the questionable proposition of mixing electronics and water. By analyzing the change in light intensity as the valve closes or opens, you can take input for a range of values or set a threshold for an on/off condition.

[Aitchison] designed these for an escape room, but we can see them being great for museums, amusement parks, or even for (train) simulators. He says one of the main reasons he picked plumbing valves was for their aesthetics. Industrial switches and arcade buttons have their place, but certainly aren’t the best fit in some situations, especially if you’re going for a period feel. Plus, since the sensor itself doesn’t have any moving parts, these analog inputs will be easy to repair should anything happen to the valve itself.

If you’re looking for more unusual inputs, check out the winners of our Odd Inputs and Peculiar Peripherals contest or this typewriter that runs Linux.

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A three picture sequence, with the first picture being a woman in a blue lit up prom dress touching a wand to her hand, the second picture being a woman in a pink lit up dress touching a wand to her hand and the third picture being the same woman in a lit up pink prom dress holding a blue glowing star wand over her head

Be The Star Of The Evening With This Light Up Prom Dress

October 12, 2022 by Abe Connelly 8 Comments

[Kellechu] went full parent beast mode by creating a prom dress for her daughter. This incredible build is a tour-de-force of DIY crafting, combining sewing, electronics, 3D printing and programming.

The dress skirt is made of tulle that allows for the LED strip underneath to diffuse through. The top bodice is made of fiber optic fabric sewn between the fabric form with the dangling fiber optic threads grouped into bundles. The dangling fiber optic bundles were then inserted and glued into “out caps” that forced the strands to sit next to a NeoPixel LED. A 20 NeoPixel “Dots Strand” strip was strung around the waist line, affixing 12 of the NeoPixels with an “out cap” to light up the fiber optic bodice. The remaining NeoPixels were outfitted with a diffuser cap and hung lower to light up the tulle skirt portion of the dress.

A wand was 3D printed and housed with an RFM69HCW Packet Radio M0 Feather, a NeoPixel LED color ring and a TCS34725 Flora color sensor powered by a 2.2 Ah 3.7 V LiPo battery. Another RFM69HCW Packet Radio M0 Feather was placed in the dress to be able to receive messages from the wand so that the sensed color could be transmitted and the LED strip could be updated with the sensed color. The dress portion was powered by a 10 Ah 3.7 V LiPo, with the battery and electronics fitting snugly into yoga bike shorts with side pockets.

[Kellechu]’s Instructable is full of details about the process and is worth checking out. For example, [Kellechu] goes into detail about the troubles and care taken when dealing with the different media, making sure to avoid ironing the fiber optics so as not to melt the lines and experimenting with different sewing needles to limit the amount of dead fibers as collateral damage from the sewing process.

Dresses with LEDs and other lights are a big hit, as can be seen from our feature on an LED wedding dress.

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