Homemade Smart Glasses Shows Why Smart Glasses Are Hard

June 26, 2016 by Donald Papp 13 Comments

[Harris Shallcross] decided to build a pair of smart glasses and recently completed a first prototype of his project ‘Ochi’ – an STM32 based, BLE-connected, OLED eyeglass display. There are of course several homebrew smart glasses projects out there; many are more polished-looking and nearly all of them also display information from a smartphone over Bluetooth. This one is interesting partly because it highlights many of the design challenges that smart glasses and other near-eye displays face. It also demonstrates the iterative development process: begin by getting something working to learn what does and doesn’t cut it at a basic level, and don’t optimize prematurely; let the process bring problems to the surface.

For his project, [Harris Shallcross] used a small 0.95″ diagonal 96×64 color OLED as the display. The lens is from a knockoff Google Cardboard headset, and is held in a 3D printed piece that slides along a wire rail to adjust focus. The display uses a custom font and is driven by an STM32 microcontroller on a small custom PCB, with an HM11 BLE module to receive data wirelessly. Power is provided by a rechargeable lithium-ion battery with a boost converter. An Android app handles sending small packets of data over Bluetooth for display. The prototype software handles display of time and date, calendar, BBC news feed, or weather information.

Devices like these have a lot to deal with. Weight and distribution of that weight is a concern, the size and comfort of the optics is important, and displaying data on a small OLED is only part of the battle – choosing what information to display and when are vital to the device being actually useful in any way, otherwise it’s just a tech demo.

This project set out to show whether it was possible to use the parts listed to make a glasses mounted smart display that was at least somewhat functional, and the software to support it. Clearly, [Harris Shallcross] succeeded at that, but what really showcases the development process is his list of improvements – what he decided needs to go into a second version, and why. One of those goals is to improve the optics; perhaps there’s something to learn from The $60 Bluetooth Head Mounted Display project, which used a similar OLED and a prism to locate the display off to the side instead of in front.

Autonomous Musical Soundscapes From 42 Fans And 7 Lasers

June 24, 2016 by Donald Papp 6 Comments

[dmitry] writes in to let us know about a new project that combines lasers with fans and turns the resulting modulation of the light beams into an autonomous soundscape. The piece is called “divider” and is a large, wall-mounted set of rails upon which seven red lasers are mounted on one end with seven matching light sensors mounted on the other end. Interrupting the lasers’ paths are forty-two brushless fans. Four Arduino Megas control the unit.

Laser beams shining into light sensors don’t do much of anything on their own, but when spinning fan blades interrupt each laser beam it modulates the solid beams and turns the readings of the sensors on the far end into a changing electrical signal which can be played as sound. Light being modulated by fan blades to create sound is the operating principle behind a Fan Synth, which we’ve discussed before as being a kind of siren (or you can go direct to that article’s fan synth demo video to hear what kind of sounds are possible from such a system.)

This project takes this entire concept of a fan synth further by not only increasing the number of lasers and fans, but by tying it all together into an autonomous system. The lasers are interrupted repeatedly and constantly, but never simultaneously. Listen to and watch it in action in the video below.

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Behold: Valve’s VR And AR Prototypes

June 22, 2016 by Donald Papp 16 Comments

Just in case anyone secretly had the idea that Valve Software’s VR and other hardware somehow sprang fully-formed from a lab, here are some great photos and video of early prototypes, and interviews with the people who made them. Some of the hardware is quite raw-looking, some of it is recognizable, and some are from directions that were explored but went nowhere, but it’s all fascinating.

ValvePrototypeVIsit-172-Medium — An early AR prototype that worked like looking through a tube into another world.

The accompanying video (embedded below) has some great background and stories about the research process, which began with a mandate to explore the concepts of AR and VR and determine what could be done and what was holding things back.

One good peek into this process is the piece of hardware shown to the left. You look into the lens end like a little telescope. It has a projector that beams an image directly into your eye, and it has camera-based tracking that updates that image extremely quickly.

The result is a device that lets you look through a little window into a completely different world. In the video (2:16) one of the developers says “It really taught us just how important tracking was. No matter [how you moved] it was essentially perfect. It was really the first glimpse we had into what could be achieved if you had very low persistence displays, and very good tracking.” That set the direction for the research that followed.

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CNC Upgrade To Guitar Pickup Winding Machine

June 18, 2016 by Donald Papp 34 Comments

The idea of winding inductive guitar pickups by hand is almost unthinkable. It uses extremely thin wire and is a repetitive, laborious process that nevertheless requires a certain amount of precision. It’s a prime candidate for automation, and while [Davide Gironi] did exactly that, he wasn’t entirely satisfied with his earlier version. He now has a new CNC version that is more full-featured and uses an ATMega8 microcontroller.

[Davide Gironi]’s previous version took care of winding and counting the number of turns, but it was still an assisted manual system that relied on a human operator. The new upgrade includes a number of features necessary to more fully automate the process, such as a wire tensioner, a wire guide and traverse mechanism (made from parts salvaged from a broken scanner), and an automatic stop for when the correct number of turns has been reached.

All kinds of small but significant details are covered in the build, such as using plastic and felt for anything that handles the wire — the extremely fine wire is insulated with a very thin coating and care must be taken to not scratch it off. Also, there is the need to compute how far the traverse mechanism must move the wire guide in order to place the new wire next to the previously-laid turn (taking into account the winding speed, which may be changing), and doing this smoothly so that the system does not need to speed up and slow down for every layer of winding.

This system is still programmed by hand using buttons and an LCD, but [Davide Gironi] says that the next version will use the UART in order to allow communication with (and configuration by) computer – opening the door to easy handling of multiple winding patterns. You can see video of the current version in action, below.

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How To Make A Custom LCD From Scratch

June 17, 2016 by Donald Papp 17 Comments

If you have ever wondered what it took to make your own custom graphic LCD from scratch, this video from [Applied Science] is worth a watch. It’s concise and to the point, while still telling you what you need to know should you be interested in rolling your own. There is also a related video which goes into much more detail about experimenting with LCD technology.

[Applied Science] used microscope slides and parts purchased online to make an LCD that displays a custom graphic when activated. The only step that home experimenters might have trouble following is coating the glass slides with a clear conductive layer, which in the video is done via a process called sputtering to deposit a thin film. You don’t need to do this yourself, though. Pre-coated glass is readily available online. (Search for Indium-Tin Oxide or ‘ITO’ coated glass.)

The LCD consists of a layer of liquid crystal suspended between two layers of conductive glass. An electrical field is used to change the orientation of crystals in the suspension, which modulate the light passing through them. Polarizing filters result in a sharp contrast and therefore a visible image. To show a particular shape, some of the conductive coating is removed from one of the layers in the shape of the desired image. The process [Applied Science] uses to do this is nearly identical to etching a custom PCB. Continue reading “How To Make A Custom LCD From Scratch” →

Evaluating The Unusual And Innovative Perf+ Protoboard

June 16, 2016 by Donald Papp 56 Comments

Back in 2015 [Ben Wang] attempted to re-invent the protoboard with the Perf+. Not long afterward, some improvements (more convenient hole size and better solder mask among others) yielded an updated version which I purchased. It’s an interesting concept and after making my first board with it here are my thoughts on what it does well, what it’s like to use, and what place it might have in a workshop.

Perf+ Overview

One side of a Perf+ 2 board. Each hole can selectively connect to bus next to it with a solder bridge. The bus strips are horizontal on the back side. — One side of a Perf+ board. Each hole can selectively connect to the bus next to it with a solder bridge. These bus strips are vertical. The ones on the back are horizontal.

The Perf+ is two-sided perfboard with a twist. In the image to the left, each column of individual holes has a bus running alongside. Each hole can selectively connect to its adjacent bus via a solder bridge. These bus traces are independent of each other and run vertically on the side shown, and horizontally on the back.

Each individual hole is therefore isolated by default but can be connected to one, both, or neither of the bus traces on either side of the board. Since these traces run vertically on one side and horizontally on the other, any hole on the board can be connected to any other hole on the board with as few as two solder bridges and without a single jumper wire.

It’s an innovative idea, but is it a reasonable replacement for perfboard or busboard? I found out by using it to assemble a simple prototype.

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Low Cost Optics Bench Project – Now With Lasercut Optics

June 14, 2016 by Donald Papp 17 Comments

[PWalsh] has a clever idea for learning and experimenting with basic optics: instead of using actual lenses, he’s using clear pieces of laser-cut acrylic cut into lens profiles instead. They are much easier to make, mount, adjust, and handle while still bending light in the same basic ways. It allows for simple hands-on experimentation with plenty of visual feedback – perfect for beginners.

This idea is part of [PWalsh]’s low-cost optics bench project, which uses laser-cut plastic to create adjustable optics bench components. We’ve covered this project before, but [PWalsh] expanded the idea with the concept of these simple laser-cut optics for basic experimentation; an addition that requires no additional tools and only a small amount of material. Features and value added for nearly zero cost is something we always love to see!

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