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There are plenty of cheap projection clocks available, but as [Thomas Pototschnig] points out in this project, where’s the fun in just buying something? He set out to build a cheap projection clock using a small LCD screen, a cheap LED backlight, and a cheap lens. Cheap is the order of the day here, and [Thomas] succeeded admirably, creating a design that can be made with a couple of cheap PCBs, a 3D printer and the other parts mentioned above. He does a nice job of laying out his thinking in this design, showing how he calculated the projection path and made other decisions. His project has room to grow as well: it runs from an Arduino compatible STM32 that could handle many things other than showing the time if you were inclined to expand the project further.

[Thomas] has released all of the files he created for the project, including a number of options for the case that can use C-mount and Sony E-mount lenses. I’m not sure if you would want to attach your expensive camera lenses to a home-made projector like this, but it’s good to have the option if you have a dead E-mount lens that you were going to tear apart for parts anyway.

Light painting is a technique which allows you to “draw” on a photograph by moving a light past the camera during a long exposure shot. While it can be difficult to master, light painting allows for some incredible effects such as text and images that appear to be hovering in mid-air. Think of it like a very slow but much cooler version of an augmented reality app.

[Reven] recently wrote in to tell us about the Arduino light painter he put together, and while DIY (and even commercial) light painting gear isn’t exactly new at this point, we think he’s raised the bar a bit with his design. With the addition of a slick 3D printed enclosure and on-board display and menu system, his light painter looks exceptionally professional for being built out of hardware he had on hand.

On his blog, [Reven] has done a phenomenal job of documenting the build from start to finish. Not only does he include a detailed Bill of Materials and the STL files so you can build your own version of his light painter, he walks the reader though his design process and explains why he did the things he did. Even if you aren’t interested in building a light painter, there’s almost certainly something of interest for anyone who’s ever looked at a pile of parts on their workbench and wondered how they were going to turn it into a functioning device.

Powered by an Arduino Uno, the light painter provides a user interface on a 16×2 LCD which allows control over not only the brightness of the WS2812 LED strips but selecting and loading different images from the micro SD card. The case was designed in FreeCAD, and while [Reven] mentions there are a number of issues which could be improved, satisfies all his design goals.

We covered the original Adafruit project that [Reven] based his code all the way back in 2013, though there’s certainly been more modern interpretations of the idea since then.

When tossing something into the rubbish bin, do you ever concoct that momentary mental scenario where you’re on a basketball court charging the net — the game’s final seconds ticking down on the clock — making a desperate stretch and flicking some crumpled paper perfectly into the basket only for no one to notice your awesome skills? Well, now you can show off how good you are at throwing out garbage.

Well, not strictly garbage. The genesis of this IoT basketball hoop was in fact an inflatable ball on [Brandon Rice]’s desk that he felt would be more fun to fidget with if he could keep score. The hoop and backboard were laser cut on his Epilog cutter, and sport a Particle Photon to track and upload his running point tally to the Internet. An Arduino and IR sensor detect objects passing through the hoop — ultrasound proved to be too slow to keep up with [Rice]’s shots.

This smart hoop also has an LCD screen which displays [Rice]’s score, and a strip of LEDs that flash every five points. Not a bad way to spend $50, if you ask him. With the advent of smart basketball nets, there will be robots out-shooting us at free-throws in no-time. Wait, that’s already happened?

[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.

Making LED lighting interactive comes in many different shapes and forms, and as the disk above shows, shifting color patterns can be pleasantly relaxing.

Some dogs have no sense of self-preservation. Given the opportunity, they will eat until they’re sick. It’s up to us humans to both feed them and remember doing it so they aren’t accidentally overfed. In a busy household with young children, the tricky part is the remembering.

[Bryan]’s family feeds their dog Chloe once a day, in the mornings. She was a rescue who spent a few years scrounging for meals on the street, so some part of her is always interested in finding food, even if she just ate. Each morning, the flurry of activity throughout the house is compounded by Chloe’s repeated requests for food, so [Bryan] got his kids involved and built a simple circuit that lets everyone know—at a glance—whether Chloe was fed.

Chloe’s kibble is kept in a touch-top wastebasket that flips open at the press of a button. [Bryan]’s dog-fed detector uses a reed switch and an Arduino clone to detect when the lid is opened. When the reed switch goes, low, the Arduino lights up an LED. The light stays on for two hours and then shuts off automatically to get ready for the next day. You don’t have to beg for a demo video, because it’s waiting for you after the break.

Since Chloe devours a bowl of food in about two minutes flat, maybe the next project for [Bryan]’s family could teach her to slow down a bit.

How do you get to sleep at night? For some of us, it can be the most difficult thing we do all day. Worrying about falling asleep and letting other intrusive thoughts in night after night only compounds the problem, as less sleep leads to depression which (for us) leads to even less sleep. We lay there, trapped inside a vortex of churning thoughts, imprisoned in a mind that feels like it’s malfunctioning and half-wishing for a future where instructor-led meditation videos can be beamed to the insides of our eyelids. In the meantime, there is FADing, the Fall Asleep Device.

FADing takes its cues from a relaxation technique that uses light to focus your attention and control your breathing. The light’s intensity waxes and wanes on a schedule designed to get you down from the average eleven breaths per minute to a zen-like six breaths per minute. You surrender to the light, breathing in as it intensifies and breathing out as it fades. There are commercial products that bring this technique to the bedroom, but they aren’t cheap and don’t offer much control. Fail to fall asleep in the prescribed window and you’re back to square one with one more thing to think about: buyer’s remorse.

[Youz] was inspired by these devices but dissatisfied with the price tag and lack of options, so he created his own version with a flexible window of operation that appeals to both back- and side-sleepers. It uses an Arduino Nano and two momentaries to control two LEDs, a relay to hold the power after startup, a 9V, and a diode to protect the Nano. One LED projects on the ceiling, and the other radiates through a slice of acrylic which has been shaded blue. One button is for power, and the other lets you add time by two-minute increments. You can see the build video after the break and then tell us how you’d do it with a 555, a coin cell, and a chunk of uranium glass in the comments.

Once you can focus on your breathing without a light, reuse that Nano to measure the quality of all that sleep you’re getting.

Retro tech is almost always ripe for the hacking — be it nostalgia, an educational teardown, or acknowledging and preserving the shoulders upon which we stand. Coming across an old West-German built flip clock, YouTuber [Aaron Christophel] retrofitted the device while retaining its original mechanical components!

No modern electronics are complete without LEDs of some kind, so he has included a strip in the base of the clock face for visibility and cool factor. He doesn’t speak to the state of the clock beforehand, but he was able to keep the moving bits of the clock working for its second shot at life.

Controlling the clock is an Arduino Mini Pro and a simple DS1307 RTC board housed within the clock itself. Originally, it had a conspicuous external box that housed the electronics and power supply that has now been rendered obsolete — or ready for re-purposing another day! Code for the Arduino is an efficient few lines using a pair of libraries. All it needs to do is flip the polarity of the electromagnet motor every minute to update the time.

We like an elegant hack once in a while and sometimes retro tech lends itself to exactly that.

[Modustrial Maker] is at it again with another seriously cool LED visualizer. This time around, he’s built pair of pendant lights inspired by the rings of Saturn.

The rings are made mostly of walnut plywood using a circle router jig to make the cut easier. If you are inspired to make these for yourself, [Modustrial Maker] is clear — the order in which you cut out the pieces of the rings is absolutely critical. The pieces are glued together — with any edges sanded smooth — and edgebanding applied using a hot air gun due to the curved surface before staining. Duplicate for the second (or more if you so choose!) rings. Be forewarned — a little geometry will be needed to find anchor points that will keep the rings properly balanced.

[Modustrial Maker] suggests an off-the shelf LED controller to handle the visualizations and lighting effects, but he used an Arduino Mega clone as the brains — code available here, a MonkeyJack MAX9814 electret mic, and a four-channel RF remote/transceiver to control the different modes. Pulsing along to the music, these rings make for sleek lighting indeed.

Link this pendant light to a radio telescope, and you might be able to achieve a real-time visualization of the radio emissions from Saturn itself!

[Thanks for the tip, Itay!]


Filed under: Arduino Hacks, LED Hacks

Old boomboxes make great hacks. Their design is iconic; yes they look dated but that really just builds on the nostalgic urge to have one hanging around. Plus their big cases simply invite adding things inside in a way impossible with contemporary electronics.

[Danc0rp] hacked his JVC M70 boombox to make the speakers glow with animated light, bumping VU meters, and a pulsing horizontal bar above the tape deck. The effect is superb. The cones of the speakers act like a projection surface and the grilles hide the LEDs until they activate, and enhance the effects once unleashed. It is one of the best LED speaker hacks we’ve ever seen.

Custom board with Arduino UNO
Custom board with Arduino UNO

The light effects are provided by LED strips, which for the speakers are attached just inside the outer rim. The brains behind it all is an Arduino UNO. To connect to it, he soldered components to a blank Arduino prototyping board. That board takes input from the boombox’s line-out and does some filtering (an attempt to address some ground noise) before passing the signal on to the Arduino. That board also interfaces between the Arduino and the LED strips. The schematic is available on his GitHub page. He’d like to replace the board with a custom PCB instead and is looking for design help.

The result is not only beautiful but professional looking too. This makes us wonder why boomboxes don’t come this way. See it for yourself in the video below.

Maybe you don’t have a boombox or want to start from scratch. In that case, check out this artfully made wooden one or this custom one in a rugged, homemade case that you’d swear on first glance was military issue.


Filed under: Arduino Hacks, LED Hacks

For all the hustle and bustle of the holiday season, people still find ways to make time for their passions. In the lead up to Christmas, [Edwin Mol] and a few co-workers built themselves an LED Christmas tree that adds a maker’s touch to any festive decor.

Before going too far, they cut out a cardboard mock-up of the tree. This an easy step to skip, but it can save headaches later! Once happy with the prototype, they printed off the design stencils and cut the chunks of clear acrylic using power tools — you don’t need a laser cutter to produce good stuff — and drilled dozens of holes in the plastic to mount LEDs, and run wires.

A Raspberry Pi 3 and Arduino Uno make this in league with some pretty smart Christmas trees. MAX6968 5.5V constant-current LED driver chips and MOFSETs round out the control circuit. During the build, the central LED column provided a significant challenge — how often do you build a custom jig to solder LEDs? That done, it’s time for a good ol’-fashioned assembly montage! The final product can cycle through several different lighting animations in a rainbow of colours — perfect for a festive build.

Even though Christmas has just passed, your holiday hacks are still flooding in! While you wait for us to push those out the metaphorical door, check out some of our other favorites like this massive pixel display, a free-formed LED tree, and a Raspberry Pi gingerbread house.


Filed under: Arduino Hacks, Holiday Hacks


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