Hackaday Prize Entry: Cheap Visible Light Communication

September 3, 2016 by Gerrit Coetzee 24 Comments

[Jovan] is very excited about the possibilities presented by Visible Light Communication, or VLC. It’s exciting and new. His opening paragraphs is filled with so many networking acronyms that VLC could be used for, our browser search history now looks like we’re trying to learn english without any vowels.

In lots of ways he has good reason to be excited. We all know that IR can communicate quite a bit, but when you’re clever about frequency and color and throw in some polarizers with a mix of clever algorithms for good measure you can get some very high bandwidth communication with anything in line of site. You can do it for low power, and best of all, there are no pesky regulations to stand in your way.

He wants to build a system that could be used for a PAN (Personal Area Network). To do this he’ll have to figure out a way to build the system inexpensively and using less than a watt of power. The project page is full of interesting experiments and quite a few thesis on the subject of LEDs.

For example, he’s done work on how LEDs respond to polarization. He’s tested how fast an LED can actually turn on and off while still being able to detect the change. He’s also done a lot of work characterizing the kind of light that an LED emits. We don’t know if he’ll succeed yet, but we like the interesting work he’s doing to get there.

Altitude Controlled LED Jacket Changes Color As You Climb

September 3, 2016 by Jenny List 6 Comments

When your climbing gym throws a “glow in the dark” party, how can you stand out? For [Martijn], the answer was obvious. He made a jacket adorned with 32 WS2812 addressable LEDs whose color is addressable depending on the altitude to which he has climbed.

The build is centered on an Arduino Pro Mini with a barometric sensor and an NRF24L01 for radio communications. A pair of pockets contain AA batteries for power, and he’s all set to climb. A base station Arduino with the same set-up transmits an up-to-the-minute reading for ground level temperature, which is compared to the local reading from the barometric sensor and used to calculate a new color for the LEDs. A Kalman filter deals with noise on the pressure reading to assure a stable result. Arduino sketches for both ends are provided on the project’s Hackaday.io page.

The LEDs are mounted on the jacket’s stretch fabric with an excess of wire behind the scenes to cater for the stretch. You can see the resulting garment in the short YouTube video below the break.
Continue reading “Altitude Controlled LED Jacket Changes Color As You Climb” →

Hacklet 123 – Watches

September 3, 2016 by Adam Fabio 22 Comments

Time and tide wait for no man. Chaucer may be right, but a man (or woman) wearing a watch can get ahead of time before it sneaks up on them. People aren’t ever satisfied with just the time though. They want the date, the phase of the moon. [Woz] summed it up pretty well when he said “I want the entire smartphone, the entire Internet, on my wrist”. Hackers love watches too, which means there are plenty of watch projects out there. Some of them even tell time. This week we’re looking at some of the best watch projects on Hackaday.io!

We start with [Max.K] and Chronio. You might think Chronio looks a bit like the Pebble Time, and you’d be right! [Max] based his design heavily on Pebble’s case design. Pebble even has their CAD files on GitHub, which helped [Max] with his modified, 3D printed version. Chronio is Arduino based, using an ATmega328p microcontroller with the Arduino bootloader. The display is Sharp’s 96×96 pixel Memory LCD. A DS3231 keeps the time accurate, and provides a free temperature sensor. The entire watch is powered by a CR2025 battery. Running a 20uA sleep current, [Max] estimates this watch will last about 6 months on a single battery.

Next we have [Joshua Snyder] and Neopixel pocket watch. Who said a watch has to go on your wrist? [Joshua] brings some steampunk style to the party. His watch uses an Adafruit 12 NeoPixel ring to tell time. Red, blue, and green LEDS represent the hour, minute and second hands. The watch is controlled by an ESP8266. The time is set via WiFi. Between the LEDs and the power-hungry ESP8266, this isn’t exactly a low-power design. A 150mAh LiPo battery should keep things running for a few hours though. That’s more than enough time to make a splash at the next hackerspace event.

Next up is [ipaq3115] and The Pi Watch. Round smartwatches have created a market for round LCD screens. These screens have started to trickle down into the hacker/maker market. [ipaq3115] got his hands on one, and had to design something cool with it. The Pi Watch isn’t powered by a Raspberry Pi, but a Teensy 3.1. [ipaq3115] included the Freescale/NXP Kinetis processor and MINI54 bootloader chip on his own custom board. He used the Teensy’s analog inputs to create his own 10 element capacitive touch ring. This watch even has a LSM303 magnetometer/accelerometer. All this power comes at a cost though. It takes a 480 mAh LiPo battery to keep The Pi Watch Ticking.

Finally we have [Vikas V] and ScrolLED watch. Who says a watch has to have an LCD? [Vikas V] wanted a scrolling LED display on his wrist, so he built his own. An Atmel ATmega88V-10AU controls a 16×5 charlieplexed LED array. [Vikas] included a character font with many of the ASCII symbols in flash, so this watch can display messages. Power comes from a CR2032 watch battery in a custom PCB mounted holder. [Vikas] biggest issue so far has been light leaks from LED to LED. He’s considering mounting the array on the bottom of the watch. Shining the LEDs up through holes in the PCB would definitely help with the light leakage.

If you want to see more watch projects, check out our new watch projects list. Notice a project I might have missed? Don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

10,000 Lumen Sunrise Lamp Curses The Darkness

September 2, 2016 by Richard Baguley 26 Comments

Some of us need a bit of help to get up in the mornings. This can come in the form of a sunrise lamp, which simulates the light of the sunrise to fool our poor sleep-deprived brains into waking up in the depths of winter. [Lincoln Johnson] found the ones he tried were not bright enough to wake him, so he decided to build his own: a 10,000-lumen monster that can wake him up from across the room.

It uses a lot of LEDS: 5 meters of 5630 LED strip, which pulls a circuit bending 72 watts when running at full blast. This monstrosity is powered by an Arduino Pro, which is programmed to slowly increase the brightness over a period of 30 minutes, thus simulating the sunrise. It uses PWM control to fade the LEDs, and also includes a dot matrix display to show the time. Honestly, if you are able to sleep through this thing blasting your eyes, you are probably dead.

“Starry Night” Dress Shines On The Experience Of Multiple Builds

September 2, 2016 by Donald Papp 10 Comments

[Dave Hrynkiw] wrote up some practical and useful detail around embedding electronics into clothing. It centers around his daughter’s “Starry Night” high school graduation dress, which is the culmination of a lot of experimentation in finding the best way to do things. His daughter accented the dress with LEDs to produce a twinkling starfield effect, and a laser-cut RGB pendant to match.

While [Dave] is the president of Solarbotics and pitches some products in the process of writing it all up, the post is full of genuinely useful tips that were all learned though practical use and experimentation. Imagine how awesome it must be growing up a child of a “local technology-hacking company” founder — akin to growing up as Willy Wonka’s progeny.

What advice does [Dave] have for making electronics an awesome part of garments? For example, the fact that regular hookup wire isn’t very well suited to embedding into clothing due to the need for high flexibility. There is also the concept of sequestering electronics into a separate Technology Layer — a must for anything that will be used more than once. The idea is to “build your technology so it can be isolated from the fashion aspect as much as possible. It makes building and maintenance of both the fashion and technology aspects much simpler.”

Slapping some LEDs and a battery pack into clothing might do the trick if all you care about is some bling, but if you want something that actually highlights and complements clothing while also being able to stand up to repeated use, this is a great read. A simple lighting effect that complements a design isn’t difficult, and there’s no need to reinvent the wheel or make the same mistakes others have encountered. Video is embedded below.

Continue reading ““Starry Night” Dress Shines On The Experience Of Multiple Builds” →

NES Light Gun Fires Awesome Laser Effect

August 31, 2016 by Gerrit Coetzee 26 Comments

[Seb Lee-Delisle]’s NES lightgun gave us pause as the effect is so cool we couldn’t quite figure out how he was doing it at first. When he pulls the trigger there erupts the beam of light Sci Fi has trained us to expect, then it explodes in a precision sunburst of laserlight at the other end as smoke gently trails from the end of the barrel. This is a masterpiece of hardware and trickery.

seb-lee-delisle-nes-zapper-trick-thumb — Demo video posted by @seb_ly

The gun itself is a gutted Nintendo accessory. It looks like gun’s added bits consist of two LED strips, a laser module (cleverly centered with two round heatsinks), a vape module from an e-cigarette, a tiny blower, and a Teensy. When he pulls the trigger a cascade happens: green light runs down the side using the LEDs and the vape module forms a cloud of smoke in a burst pushed by the motor. Finally the laser fires as the LEDs finish their travel, creating the illusion.

More impressively, a camera, computer, and 4W Laser are waiting and watching. When they see the gun fire they estimate its position and angle. Then they draw a laser sunburst on the wall where the laser hits. Very cool! [Seb] is well known for doing incredible things with high-powered lasers. He gave a fantastic talk on his work during the Hackaday Belgrade conference in April. Check that out after the break.

So what does he have planned for this laser zapper? Laser Duck Hunt anyone? He has a show in a month called Hacked On Classics where this build will be featured as part of the Brighton Digital Festival.

Continue reading “NES Light Gun Fires Awesome Laser Effect” →

Charliplexed 7-Segment Display Takes Advantage Of PCB Manufacturers

August 23, 2016 by Elliot Williams 32 Comments

Cutting out precise shapes requires a steady hand, a laser cutter, or a CNC mill, right? Nope! All you need is PCB design software and a fabrication facility that’ll do the milling for you. That’s the secret sauce in [bobricius]’s very pleasing seven-segment display design.

His Hackaday.io entry doesn’t have much detail beyond the pictures and the board files, but we’re not sure we need that many either. The lowest board in the three-board stack has Charlieplexed LEDs broken out to six control pins. Next up is a custom-routed spacer board — custom routed by the PCB house, that is. And the top board in the stack is another PCB, this one left clear of copper where the light shines out.

We want to see this thing lit up! We’ve played around with using PCB epoxy material as a LED diffuser before ourselves, and it can look really good. The spacers should help even out the illumination within segments, while preventing bleed across them. Next step? A matrix of WS2812s with custom-routed spacers and diffusers. How awesome would that be?