Hyperspectral Imaging – Seeing The Unseeable

They say that a picture is worth a thousand words. But what is a picture exactly? One definition would be a perfect reflection of what we see, like one taken with a basic camera. Our view of the natural world is constrained to a bandwidth of 400 to 700 nanometers within the electromagnetic spectrum, so our cameras produce images within this same bandwidth.

Image via Cosmos Magazine.

For example, if I take a picture of a yellow flower with my phone, the image will look just about how I saw it with my own eyes. But what if we could see the flower from a different part of the electromagnetic spectrum? What if we could see less than 400 nm or greater than 700 nm? A bee, like many other insects, can see in the ultraviolet part of the spectrum which occupies the area below 400 nm. This “yellow” flower looks drastically different to us versus a bee.

In this article, we’re going to explore how images can be produced to show spectral information outside of our limited visual capacity, and take a look at the multi-spectral cameras used to make them.  We’ll find that while it may be true that an image is worth a thousand words, it is also true that an image taken with a hyperspectral camera can be worth hundreds of thousands, if not millions, of useful data points. Continue reading “Hyperspectral Imaging – Seeing The Unseeable”

Friday Hack Chat: DMX512 Gon’ Give It To Ya

DMX512 is the standard for theatrical lighting, and it’s best described as, ‘MIDI for lights’. It’s been around since the 80s, and in the decades since it’s been used, abused, and shoved into just about everything imaginable.

For this week’s Hack Chat, we’re talking all about DMX512. What is DMX512? How does it work? What can you control with DMX512? What Open Source projects use it? There’s a wealth of information out there, and a lot of very cool tricks you can pull with this ubiquitous lighting protocol.

Our guest for this week’s Hack Chat is [Martin Searancke], owner of Dream Solutions Ltd. [Martin] was contacted early on in the development of Coca-Cola’s impressive 3D Times Square advertisement to see if Dream Solution’s LightFactory software could be used to drive this 3D screen. This software has pixel mapping and media playback capabilities and was used for the prototypes for the project. A subset of this product made it into the final installation, and is now driving a gargantuan display above Times Square in New York City.

This is a community Hack Chat, and of course we’re taking questions from the community. If you have a question you’d like to ask [Martin], add it to the discussion sheet.

join-hack-chatOur Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. Our Hack Chats usually take place at noon, Pacific time on Friday, but this week is different. [Martin] is in New Zealand, so this Hack Chat is happening at 2pm Pacific, Friday, October 27th. Is that too hard for you? Here’s a time zone converter!

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

We’re also looking for new Hack Chat hosts! If you’ve built something cool, you’re working on an interesting project, or you’re about to introduce a really cool product, hit us up! Email our wonderful community managers, and we’ll see if we can slot you in.

Interference Scanner With Clear Instructions

Meticulous. Thorough. Exacting. These are all words we’d use to describe this video by [BrendaEM] about her Homemade 3D Optical Interference Scanner which can be seen after the break. The scanner uses 3D-printed parts and repurposed materials you might find lying around in your spare parts bin. An old optical drive tray acts to move the laser-wielding sled while a stripped-out webcam is an optical sensor. Links to relevant files such as 3D models and Arduino sketches will be found in the video’s author section.

The principle of operation is demonstrated with a water analog in the video at 2:00 with waves in a plastic container. By creating two small apertures between a light source and a sensor, it’s possible to measure the light waves which make it through. [BrendaEM] uses some powerful visualization software to convert her samples into 3D models which look really cool and simultaneously demonstrate the wave nature of light.

On the left side of her device are the control electronics which don’t need any special coatings since light won’t pass over this area. For the right side, where coherent light is measured, to borrow a Rolling Stones lyric: no colors anymore, I want them to turn black. Even the brass strips with apertures are chemically darkened.

Most of the laser hacks here use lasers rather than measure them, like this Laser Clock and a Laser Projector.

Continue reading “Interference Scanner With Clear Instructions”

A Passive Mixer’s Adventure Through Product Development

The year was 2014, and KORG’s volca line of pint-sized synthesizers were the latest craze in the music world. Cheap synths and drum machines were suddenly a reality, all in a backpack-friendly form factor. Now practically anyone could become an electronic music sensation!

I attended a jam with friends from my record label, and as was the style at the time, we all showed up with our latest and greatest gear. There was the microKORG, a MiniNova, and a couple of guitars, but all attention was on the volcas, which were just so much fun to pick up and play with.

There was just one problem. Like any game-changing low-cost hardware, sacrifices had been made. The volcas used 3.5mm jacks for audio and sync pulses, and the initial lineup came with a bassline, lead, and drum synth. Syncing was easy, by daisy chaining cables between the boxes, but if you wanted to record or mix, you’d generally need to stack adapters to get your signals in a more typical 6.5mm TS format used by other music hardware.

After mucking around, I did some research on what other people were doing. Most were suffering just like we were, trying to patch these little machines into full-sized mixing desks. It seemed like overkill — when you just want to muck around, it’s a bit much to drag out a 24 channel powered mixer. I wanted a way to hook up 3 of these machines to a single set of headphones and just groove out.

To solve this problem, we needed a mixer to match the philosophy of the volcas; simple, accessible, and compact. It didn’t need to be gold-plated or capable of amazing sonic feats, it just had to take a few 3.5mm audio sources, and mix them down for a pair of headphones.

I’d heard of people using headphone splitters with mixed results, and it got me thinking about passive mixing. Suddenly it all seemed so clear — I could probably get away with a bunch of potentiometers and some passives and call it a day! With a friend desperate to get their hands on a solution, I decided to mock up a prototype and took it round to the studio to try out.

Continue reading “A Passive Mixer’s Adventure Through Product Development”

NFC Enabled Business Card

[Sjaak] is back at it again with the cool PCB business cards, this time alleviating the burden to physically type his contact information into your phone. But NFC isn’t the only cool thing on this PCB – as always, his aesthetics don’t disappoint.

When we see [Sjaak’s] card, the future seems to be the now – not only do we have business cards that can take our pulse, we have business cards that actively help facilitate the exchange of contact information. I know what you’re thinking. “Business cards made of paper do that already.” That’s true if you read them. You have to physically remember you have the card (aka not put it through the wash), and, if you’re like most folks, you’ll ultimately enter the information into your cell phone’s contact list. Why not skip the whole reading thing? You know, just zap your contact information into the contact list of people automatically?

Maybe this is exactly what [Sjaak] thought when he built his NFC enabled business card. Maybe not. Regardless, [Sjaak’s] card is beautiful – both in implementation and aesthetics. Powered by “a nice little NFC EEPROM from NXP”, (the NT3H1101) the business card even has an energy harvesting mode. Moreover, one can interact with the card via four buttons and an LED. The LED informs the user what mode the card is currently in, and the buttons choose which URL is sent to users via NFC. To add icing to the cake, the back of the PCB is decked out via [Sjaak’s] custom full-color decal process we covered back in August.

As great as it looks, the card still needs some improvement. “I still need to tackle the sharp and protruding components on the front, which will ruin your wallet.” But, in our eyes, the card is surely on its way to greatness, and we look forward to seeing its final form. However, if you’re anything like us, you might want to see some other rad PCB business cards while you wait. If that’s the case, we recommend this logic based finite machine and this card made by a hackaday author.

Alas, Poor Yorick! He Hath Not Amazon Prime

If you are looking around for a Halloween project, you might consider The Yorick Project from [ViennaMike]. As you can see in the video below, it marries a Raspberry Pi acting as an Amazon Alexa with an animatronic skull.

This isn’t the most technically demanding project, but it has a lot of potential for further hacking. The project includes a USB microphone, a servo controller, and an audio servo driver board. It looks like the audio servo board is controlling the jaw movement and based on the video, we wondered if you might do better running it completely in software.

Continue reading “Alas, Poor Yorick! He Hath Not Amazon Prime”

LoRa Is The Network

We’ve become used to seeing LoRa appearing in projects on these pages, doing its job as a low-bandwidth wireless data link with a significant range. Usually these LoRa projects take the form of a client that talks to a central Internet connected node, allowing a remote wireless-connected device to connect through that node to the Internet.

It’s interesting then to see a modest application from [Mark C], a chat application designed to use a set of LoRa nodes as a peer-to-peer network. In effect LoRa becomes the network, instead of simply being a tool to access it. He optimistically describes peer-to-peer LoRa networks as the new FidoNet in his tip email to us, which might be a bold statement, but we can certainly see some parallel. It’s important to note that the application is merely a demonstrable proof-of-concept as it stands, however we’d agree that it has some potential.

The hardware used for the project is the Heltec ESP32-based LoRa board, which comes with a handy OLED screen on which the messages appear. As it stands a PC connection is required to provide text input via serial, however it’s not impossible to imagine other more stand-alone interfaces. If it interests you the code can be downloaded from the GitHub repository, so maybe this can become the seed for wider peer-to-peer LoRa networks.

There have been no shortage of LoRa projects featured here over the years. Recent ones include a handy local LoRa packet sniffer, and news of an extreme distance record from a LoRa node on a balloon.