Curved Wood LED Lamp Needs No Fancy Tools

March 20, 2018 by Donald Papp 9 Comments

Those of us who aren’t familiar with woodworking might not expect that this curved wood and acrylic LED lamp by [Marija] isn’t the product of fancy carving, just some thoughtful design and assembly work. The base is a few inches of concrete in a plastic bowl, then sanded and given a clear coat. The wood is four layers of beech hardwood cut on an inverted jigsaw with the middle two layers having an extra recess for two LED strips. After the rough-cut layers were glued together, the imperfections were rasped and sanded out. Since the layers of wood give a consistent width to the recess for the LEDs, it was easy to cut a long strip of acrylic that would match. Saw cutting acrylic can be dicey because it can crack or melt, but a table saw with a crosscut blade did the trick. Forming the acrylic to match the curves of the wood was a matter of gentle heating and easing the softened acrylic into place bit by bit.

Giving the clear acrylic a frosted finish was done with a few coats of satin finish clear coat from a spray can, which is a technique we haven’t really seen before. Handy, because it provides a smooth and unbroken coating along the entire length of the acrylic. This worked well and is a clever idea, but [Marija] could still see the LEDs and wires inside the lamp, so she covered them with some white tape. A video of the entire process is embedded below.

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NES Controller Slider-Based Light Theremin

March 20, 2018 by Kristina Panos 1 Comment

Having never use a 555 before, [lonesoulsurfer] decided that his first foray into the world’s most popular and versatile IC would be to use a 555 to make beautiful chiptunes. For that, we commend him. He found [Dean Segovis]’ Slidersynth light-based Theremin and got to work building his own version it and stuffing it into a (knockoff!) NES controller.

For the uninitiated, a Theremin is a touch-less synthesizer that uses human capacitance and a pair of antennae to control oscillation and amplitude. In a light-based Theremin such as this one, the oscillation is controlled by the intensity of photons from a white LED and their interaction with a light-dependent resistor, also known as a photocell or ‘squiggly resistor’.

The oscillations themselves are created by wiring up the 555 as an astable oscillator, and the pitch is controlled with a potentiometer mounted on the back. It has a small built-in speaker, but [lonesoulsurfer] replaced the B button with a 3.5 mm audio jack so he can plug it into a powered speaker and really rock out. We’ve got his demo tape queued up after the break.

We love pocket instruments around here. If you prefer brass and woodwinds, this pocket woodwind MIDI controller just might draw your lips into an O.

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This Big, Bright Seven-Segment Display Is 3D-Printable

March 18, 2018 by Dan Maloney 16 Comments

Seven-segment LED displays have been around forever, it seems, and the design is pretty optimized by now. Off-the-shelf units are readily available in all sorts of sizes and colors, but if you want a really big display, you might have to roll your own. Scaling up the size doesn’t necessarily mean you have to scale up the complexity, though, if this light-pipeless jumbo seven-segment LED display is any indication.

It’s clear that [Fran Blanche] has a thing for collecting and building oddball numeric displays, like this cathode ray tube Nixie knockoff or her Apollo DSKY electroluminescent display. Her plus-size seven-segment display is far less complicated than either of those, and that’s by design; [Fran] wanted something that was 3D-printable as a single part, rather than an assembly with light pipes and diffusers. To that end, the display is just a pair of X-shaped dividers stacked on top of each other behind the display’s face. They dividers form six triangular compartments and a diamond shaped one, with each compartment opening into a segment-shaped window. One LED goes in each triangular compartment, while the double-sized diamond space gets two. That’s it — the LEDs light up the inside of each compartment to turn on the appropriate segments. Watch it in action below.

The display still needs some tweaking, but it’s big and bright and has a large acceptance angle. What’s more, it’s scalable — imagine a display the size of a sheet of plywood using LED light bulbs. We’re looking forward to [Fran]’s improvements and her next display project, which appears to use hot glue as a light pipe.

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LED Illusion Makes Colorful Water Drops Defy Gravity

March 14, 2018 by Dan Maloney 15 Comments

The 60s and 70s were a great time for kitschy lighting accessories. Lava lamps, strobes, color organs, black light posters — we had it all. One particularly groovy device was an artificial rain display, where a small pump dripped mineral oil over vertical monofilament lines surrounding a small statue, with the whole thing lighted from above in dramatic fashion. If it sounds appalling, it was, and only got worse as the oil got gummy by accumulating dust and debris.

While this levitating water drops display looks somewhat similar, it has nothing to do with that greasy lamp of yore. [isaac879]’s “RGB time fountain” is actually a lot more sophisticated and pretty entrancing to watch. The time fountain idea is simple — drip water from a pump nozzle to a lower receptacle along a path that can be illuminated with flashing LEDs. Synchronizing the flashes to the PWM controlling pump speed can freeze the drops in place, or even make them appear to drip up. [isaac879] took the time fountain idea a step further by experimenting with RGB illumination, and he found that all sorts of neat effects are possible. The video below shows all the coolness, like alternating drops of different colors that look like falling — or rising — paint drops, and drops that merge together to form a new color. And behold, the mysterious antigravity cup that drips up and yet gets filled!

Allowances must be made for videos of projects that use strobes, of course. The effect of this time fountain and similar ones we’ve featured before is hard to capture, but this one still looks great to us.

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Interactive Plant Lamps For Quiet Spaces

March 14, 2018 by Kristina Panos 4 Comments

If you’ve spent any serious time in libraries, you’ve probably noticed that they attract people who want or need to be alone without being isolated. In this space, a kind of silent community is formed. This phenomenon was the inspiration [MoonAnchor23] needed to build a network of connected house plants for a course on physical interaction and realization. But you won’t find these plants unleashing their dry wit on twitter. They only talk to each other and to nearby humans.

No living plants were harmed during this project—the leaves likely wouldn’t let much light through, anyway. The plants are each equipped with a strip of addressable RGB LEDs and a flex sensor controlled by an Arduino Uno. Both are hot glued to the undersides of the leaves and hidden with green tape. By default, the plants are set to give ambient light. But if someone strokes the leaf with the flex sensor, it sends a secret message to the other plant that induces light patterns.

Right now, the plants communicate over Bluetooth using an OpenFrameworks server on a local PC. Eventually, the plan is use a master-slave configuration so the plants can be farther apart. Stroke that mouse button to see a brief demo video after the break. [MoonAnchor23] also built LED mushroom clusters out of silicone and cling wrap using a structural soldering method by [DIY Perks] that’s also after the break. These work similarly but use force-sensing resistors instead of flex-sensing.

Networking several plants together could get expensive pretty quickly, but DIY flex sensors would help keep the BOM costs down. Continue reading “Interactive Plant Lamps For Quiet Spaces” →

RGB Disk Goes Interactive With Bluetooth; Shows Impressive Plastic Work

March 11, 2018 by Donald Papp 5 Comments

[smash_hand] had a clear goal: a big, featureless, white plastic disk with RGB LEDs concealed around its edge. So what is it? A big ornament that could glow any color or trippy mixture of colors one desires. It’s an object whose sole purpose is to be a frame for soft, glowing light patterns to admire. The disk can be controlled with a simple smartphone app that communicates over Bluetooth, allowing anyone (or in theory anything) to play with the display.

The disk is made from 1/4″ clear plastic, which [smash_hand] describes as plexiglass, but might be acrylic or polycarbonate. [smash_hands] describes some trial and error in the process of cutting the circle; it was saw-cut with some 3-in-1 oil as cutting fluid first, then the final shape cut with a bandsaw.

The saw left the edge very rough, so it was polished with glass polishing compound. This restores the optical properties required for the edge-lighting technique. The back of the disc was sanded then painted white, and the RGB LEDs spaced evenly around the edge, pointing inwards.

The physical build is almost always the difficult part in a project like this — achieving good diffusion of LEDs is a topic we talk about often. [smash_hands] did an impressive job and there are never any “hot spots” where an LED sticks out to your eye. With this taken care of, the electronics came together with much less effort. An Arduino with an HC-05 Bluetooth adapter took care of driving the LEDs and wireless communications, respectively. A wooden frame later, and the whole thing is ready to go.

[smash_hands] provides details like a wiring diagram as well as the smartphone app for anyone who is interested. There’s the Arduino program as well, but interestingly it’s only available in assembly or as a raw .hex file. A video of the disk in action is embedded below.

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Cheap And Easy Helmet Lights For The Kids

February 28, 2018 by Lewin Day 31 Comments

Bikes are a great way to get around and get exercise at the same time, and are widely popular with human children due to the fact that they’re generally not allowed to drive. However, riding on or next to the road can be dangerous, particularly at night, when even adults on bikes are hard to see. It’s far worse for the youngest children, who can be incredibly small and difficult to spot. [Patrick]’s children enjoy riding, but it can get a little sketchy at night, so he developed a solution.

The project relies on cheap, commonly available LED strip lights. Rather than any fancy addressable strips, these are just simple strings of LEDs with current limiting resistors already fitted in a convenient, adhesive backed format. This makes the job as easy as peeling off the backing tape, sticking the strips to the helmet, and providing a power source. In clsasic entry-level hack style, everything’s running off a single 9V battery. Is it as versatile as a rechargable lithium pack with integrated controller? No, but it’s a swift way to get a project off the ground.

The trick here isn’t so much the hardware side of things – there’s nothing fancy about a battery and some LEDs. The key here is that [Patrick] identified that his children are small and difficult to see, thus it made sense to fit helmet lights rather then more typical bike lights to make them more visible to surrounding traffic.

For something at the other end of the spectrum, check out this amazingly professional LED bike light.

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