Hackaday Prize Entry: Characterizing LED And Laser Diodes

Needless to say, we’re fascinated by LEDs, laser diodes, and other blinkies. Although we can get just about any light emitting thing, the data sheets aren’t always accurate or available. For his Hackaday Prize entry, [Ted] is building a device to characterize the efficiency, I/V curve, and optical properties of all the blinkies. It’s a project to make glowy stuff better, and a great entry for the Hackaday Prize.

The inspiration for this project came from two of [Ted]’s projects, one requiring response curves for LEDs, and laser diodes for another. This would give him a graph of optical output vs. current, angular light output distribution, and the lasing threshold for laser diodes. This data isn’t always available in the datasheet, so a homebrew tool is the only option.

The high-level design of this tool is basically a voltmeter and ammeter measuring a glowy diode, producing IV curves and measuring optical output. That takes care of all the measurements except for the purely optical properties of a LED. This is measured by a goniometer, or basically putting the device under test on a carriage attached to a stepper motor and moving it past a fixed optical detector.

If you’re wondering why this device is needed and a simple datasheet is insufficient, check this out. [Ted] measured the efficiency of a Luxeon Z LED, and found the maximum efficiency is right around 10mA. The datasheet for this LED shows a nominal forward current of 500mA, and a maximum of 1000mA. If you just looked at the datasheet, you could easily assume a device powered for years by a coin cell would be impossible. It’s not, and [Ted]’s device gave us this information.

Hackaday Prize Entry: Boots And Cats And Boots And Cats

Electronic drums are pricey, but the drums themselves are actually very easy to make. By simply putting a few piezos on some rubber mats, you can make a set of electronic drums. The real trick, and the expensive bit, is in the drum module. This module has inputs for the high hat, snare, toms, and bass drum to turn the repetitive thwaking of a stick on a rubber mat into drum sounds.

For his Hackaday Prize entry, [Jeremy] isn’t building a set of electronic drums. He’s building a drum module, complete with touchscreen interface and a GUI.

This isn’t [Jeremy]’s first go at building a drum module – his first implementation was RaspiDrums, an add-on for the Raspberry Pi that used accelerometers instead of piezos. The software works well enough with a USB sound card to serve as a set of real electronic snare.

Now [Jeremey] is moving up to a full kit, and the power of the Raspberry Pi means he can easily add a touch screen to his device. Right now the efforts are going into building a GUI using Gtkmm, and wrapping everything up into a front panel that makes sense and is easy to use. The drums themselves are a solved problem, making this Hackaday Prize entry a fantastic polish on an already great project.

Hackaday Prize Entry: An Electric Bike And A Dashboard

Over the last few years, powerful brushless motors have become very cheap, batteries have become very powerful, and the world of quadcopters has brought us very capable electronic speed controls. Sounds like the perfect storm for a bunch of electric bike hacks, right? That’s what [bosko] is doing for his Hackaday Prize Entry. He’s building an e-bike with a big motor and an electronic dashboard, because a simple throttle switch would never do.

There are two parts to [bosko]’s bike, with the front brain box consisting of GPS, an OLED display, analog throttle, and a few wireless modules to connect to the other half of the system under the seat.

The drive section of this e-bike is as simple as it gets. It’s just a big brushless outrunner motor suspended directly above the rear tire, without any other connection. [bosko] has gone with the simplest power transmission system here, and is slightly wearing out the rear tire in the process. It works, though, and a few of the commentors over on Hackaday.io say it reminds them of the French Solex bike. We’re thinking this bike is more of what a riquimbili would be if Hobby King had a Cuban warehouse, but it seems to work well for [bosko] and is a great entry to the Hackaday Prize.

Hackaday Prize Entry: Adblock For TV

Contact, the 1985 book by Carl Sagan, was significantly better than the movie. Five people went through the wormhole, three machines were made (in Russia, Wyoming, and a third on Hokkaido), Erbium did something, and the novelization provided much better worldbuilding. One of the more interesting characters in the book was H.R. Haddon, the megalomaniacal business man, made his first million designing a chip that would block advertisements on TV. The book strongly suggests this commercial-blocking chip was a purely analog device, a concept that would have been an amazing abuse of NTSC produced by a damn fine engineer.

Now, even though cord cutting is commonplace and streaming is taking over, there’s still commercials on Hulu. In a few months, I’ll have to pay $5 a month to watch Star Trek with commercials. There is obviously a market for ‘adblock for TV’, and that’s what [PixJuan] is doing for his Hackaday Prize entry.

[Juan]’s device is a basically an HDMI switch with a remote that’s pressed every time the ads start to show on a broadcast. This switch will change the input of the HDMI switch from a cable box to a Raspberry Pi and play a short video clip or something else that isn’t selling you crap. When the Raspi is done, the switch goes back over to the original input.

With a bit of computation in this adblock-for-TV device, there are a few more options for ad detection. The Raspberry Pi could build a database of when ads play and for how long, depending on the channel. This is a great project that has a lot of potential to use some interesting techniques like computer vision and machine learning for the goal of removing commercials before they start.

Hackaday Prize Entry: A One Hand Bottle Opener

For the next month, the Hackaday Prize is all about Assistive Technologies. You would think this means exoskeletons, 3D printed prosthetics, and better wheelchairs, and you’d be right. This project in the running for the Assistive Technologies portion of the prize isn’t what you would expect. It’s a brilliantly simple way to open a water bottle with one hand. Think of it as the minimum viable project for assistive technologies, and a brilliant use of a few 3D printed parts and some metric bolts.

The OHBO – the One Hand Bottle Opener – is just a simple 3D printed ring that fits over a water bottle. There’s a small arm attached with a few bolts that lock this ring onto the bottle. With this bottle opener attached, it only requires a simple twist of the wrist to open a screw-top bottle.

As you can see in the video below, this would be a fantastic device for anyone with one hand to keep around the fridge. Of course, like all good Hackaday Prize entries, all the files to recreate this build are available, with just a few bits of hardware required to complete the build.

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Hackaday Prize Entry: Lucid Dreaming Research

Lucid dreaming is one of the rare psychological phenomenon terrible sci-fi frequently gets right. Yes, lucid dreaming does exist, and one of the best ways to turn a normal dream into a lucid dream is to fixate on a particular object, sound, or smell. For their Hackaday Prize entry, [Jae] is building a device to turn the electronic enthusiast community on to lucid dreaming. It’s a research platform that allows anyone to study their own dreams and access a world where you can do anything.

The core of this project is an 8-channel EEG used to measure the electrical activity in the brain during sleep. These EEG electrodes are fed into a 24-bit ADC which is sampled 250 times per second by an ARM Cortex M4F microcontroller. The captured data is recorded or sent to a PC or smartphone over a Bluetooth connection where a familiar sound can be played (think of the briefcase in Inception), or some other signal that will tell the dreamer they’re dreaming.

We’ve seen a few similar builds in the past, most famously a NeuroSky MindWave headset turned into a comfortable single-channel EEG-type device. The NeuroSky hardware is limited, though, and a setup with proper amplifiers and ADCs will be significantly more helpful in debugging the meatspace between [Jae]’s ears.

Hackaday Prize Entry: Cheap Visible Light Communication

[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.