When [Vance] joined his local hackspace he sought a project to take advantage of the new tools at his disposal. His solution: an attractive LED colour wheel clock using neopixels driven by an NTP-synchronised ESP8266. Each neopixel illuminates a segment of the clock face through frosted diffuser, the hours are tracked as a red light, the minutes blue, and the seconds green. As each color passes another they are mixed, creating a changing colorscape. 12 neopixels are used, and the whole clock is mounted in a laser cut enclosure.
After an initial prototype on a piece of stripboard he created a PCB in KiCad, complete with space for a 3.3v regulator. This and the source code can be found on the project’s GitHub repository.
The resulting clock is a very high quality build as well as being attractive and useful in its own right. The video shows the color mixing in action, or at least the cyan and yellow products of it. Continue reading “Neopixel Bedroom Clock Uses ESP8266”→
Pelican makes a great remote lighting system. Unfortunately, it’s the kind of great that comes with a “Request Quote” button instead of “Add to Cart”. It’s designed to be thrown in the back of a tank and guaranteed to work at the end of the day. [mep1811]’s system is not that system. It’s the store-in-a-Rubbermaid-tote and throw in the back of the family Honda kind of great, but it’s made from stuff you can buy anywhere.
The build is contained by a water resistant plastic box. Two sealed lead acids and a battery charger sit inside. The system is hooked together with simple car outlets — also known as the worst accidental electrical connector standard of all time. For the lights, [mep1811] simply made mounts for chinese LED spots and bought some inexpensive camera tripods. With a full charge, he says it runs for forty hours.
In the end it’s not a complicated hack, but its simplicity adds a certain amount of ruggedness, and it will definitely do the trick in a power outage.
If you have ever entertained yourself by reading comprehensive electronic-theory textbooks you’ll have seen references to technologies that sound really interesting but which you will rarely hold in your hand. They may be dead-ends that have been superseded by more recent innovations, or they may be technologies that have found uses but in other fields from those in which they originally showed promise. What if you could take these crazy parts and actually build something?
If you’ve used a thermocouple thermometer or a semiconductor thermoelectric generator then you’ll have encountered the thermoelectric effect. Perhaps you’ve even operated a Peltier cooling element in this mode. When a circuit is made with two junctions between different types of conductor with a temperature difference between the two junctions, a current will flow in the circuit which is dependent on both the scale of the temperature difference and the properties of the conductors.
A thermopile is a collection of these thermoelectric junction circuits between metal conductors, arranged in series to increase the voltage. [Fedetft]’s thermopile uses chromel and alumel wires taken from a K-type thermocouple. He’s made six sets of junctions, and supported them with small pieces of mica sheet. Using the heat from a candle he found he could generate about 200mV with it, at about 3.7mW.
The RCA tunnel diode inverter circuit
Such a tiny source of electricity would be of little use to light an LED directly, so he needed to build an inverter. And that’s where the tunnel diode comes in. Tunnel diodes have a negative-resistance region that can be used to amplify and oscillate at extremely high frequencies in extremely simple circuits, yet they’re not exactly a device you’d encounter very often in 2016. [Fedetft] has a Russian tunnel diode, and he’s used it with a toroidal transformer in an inverter circuit he found in an RCA tunnel diode manual from 1963. It’s a two-component Joule Thief. The RCA manual is a good read in itself for those curious about tunnel diodes.
The resulting circuit produces a 15kHz oscillation with 4.5v peaks, and has just enough power to light an LED.
While it might seem pointless to barely light an LED from a brightly lit candle, the important part of [Fedetft]’s project is to gain some understanding of two of those technological backwaters from the textbooks. And we applaud that.
Bicycle riders can never be too visible: the more visible you are, the less chance there is someone will hit you. That’s the idea behind the Arduibag, a neat open-source project from [Michaël D’Auria] and [Stéphane De Graeve]. The project combines a joystick that mounts on the handlebars with a dot matrix LED display in a backpack. By moving the joystick, the user can indicate things such as that they are turning, stopping, say thank you or show a hazard triangle to warn of an accident.
The whole project is built from simple components, such as an Adafruit LED matrix and a Bluno (an Arduino-compatible board with built-in Bluetooth 4.0) combined with a big battery that drives the LED matrix. This connects to the joystick, which is in a 3D printed case that clips onto the handlebars for easy use. It looks like a fairly simple build, with the larger components being mounted on a board that fits into the backpack and holds everything in place. You then add a clear plastic cover to part of the backpack over the LED matrix, and you are ready to hit the road, hopefully without actually hitting the road.
[nebulous] has a lot of problems with his kitchen cabinets. Aside from a noted lack of micro-controllers, he was especially suspicious of the dark spaces under them. Anything could be hiding there.
The core of the project is a $10 Arduino-compatible esp8266 board from digistump. The board is powered by the five volt regulator of an L298N motor driver module hooked to a power-supply. All this controls a set-of LED strips adhered to the underside of the cabinets with the traditionally bad adhesive strips with which they come standard. We can predict an hour spent bent awkwardly cursing at them, a hot-glue gun in one hand, in [nebulous]’s future. The whole set-up is housed in a SparkFun cardboard box above the microwave. You can barely tell it’s not a commercial product.
We’re not certain if we like a future where even our cabinetry has an IP address. However, this is a good weekend project that could make all our cabinetry brighter, safer, and more connected.
There’s been a resurgence of interest in vacuum tubes. Even if you do think audio sounds better through a tube, you have to admit the care and feeding of filaments and plate voltages isn’t trivial. [Ed Nisley] decided to sidestep all that and just build an objet d’art that looks like a tube.
A burned out halogen bulb stands in for the tube, and a ceramic base holds the bulb. It also conceals–what else–an Arduino. The Arduino drives a knock-off Neopixel LED hidden in a faux plate cap. The result is a glass envelope bathed in a cold blue and purple glow that changes under software control.
[Brainsmoke] had a simple plan. Make a quadcopter with lots of addressable LEDs.
Not just a normal quadcopter with ugly festoons of LED tape though. [Brainsmoke] wanted to put his LEDs in a ball. Thus was born the polyhedrone, the idea of a flying deltoidal hexecontahedron covered as you might expect with all those addressable LEDs.
A Catalan solid makes a good choice for the homebrew polyhedron builder because its faces are all identical. Thus if you are making PCBs to carry LEDs, for example, you need only create a single PCB design to use on all faces. A bit of work in KiCAD, and a single face design with interlocking edges was ready. The boards were tested, a wiring layout was worked out, and the polyhedron was assembled.
But [Brainsmoke] didn’t stop there. He produced a flight case for the polyhedron, in the form of a larger polyhedron from what looks like lasercut thin ply.
Having a finished polyhedron, the next thing was to hook up a Raspberry Pi and write some software. First in Python, then in Go.
The results are simply stunning. If the mathematics and construction of a polyhedron were not enough to make this project worth a second look, then the gallery of images should be enough. You’ll notice that this is ostensibly a quadcopter project, yet no mention of flying has been made on this page. That’s because this is still a work in progress at Tech Inc Amsterdam, and there is more to come. But it honestly doesn’t matter if this project never moves a millimeter off the ground, as far as we are concerned [Brainsmoke] has created a superbly built thing of beauty in its own right, and we like that.
As you might expect, this is just the latest of many projects featured here that have involved addressable LEDs or quadcopters. Of note among them is this LED polyhedron that cleverly closes in all its bits, and this LED-equipped quadcopter that generates very pleasing patterns with a hi-res cross of pixels.
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The results are simply stunning. If the mathematics and construction of a polyhedron were not enough to make this project worth a second look, then the 
