Pulling the LCD screens out of a MyVu glasses display


[John Floren] really sells us on a pair of MyVu 301 Video Glasses. He lists the features as being bulky, ugly, and uncomfortable. That’s the reason why he’s showing you how to crack open the glasses in order to steal the tiny LCD modules.

The LCD screen for each eye is mounted inside of the assembly seen above. The screen is perpendicular to the wearer’s eye, with some space in the body to facilitate the lens and reflector that enlarge the image and direct it toward the eye. After removing the display from the module [John] tried to hook it up to a camera via the driver hardware which comes with the glasses. It must have been a bit of a head scratcher that all he could get was a plain white image. This is fixed by finding the polarizing filter inside the module and laying it over the screen. This is demonstrated in the clip after the break.

We don’t know where he’s planning to go from here, but we can suggest a few different projects. This hardware could be useful in creating his own augmented reality hat. Using it as a video game controller is another thing that pops to mind. Wouldn’t it be cool to have this in the scope sight of a light gun?

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Demystifying camcorder CRT viewfinders

Every smartphone (and most dumb phones) has a video camera built into it these days. Some of them are even capable of recording respectable HD video. So we’d bet that the decades old camcorder you’ve got kicking around isn’t getting any use at all anymore. [John] wants to encourage you to hack that hardware. He published a post showing just how easy it is to salvage and use a camcorder CRT.

The gist is that you simply need to hook up power and feed it video. The board that is attached to the CRT has its own voltage hardware to drive the tube. He demonstrates a 9V battery as a power supply, but also mentions that it should be pretty easy to power the thing from a USB port. As for video, all it takes is a composite signal. Of course you’ve got to determine the pinout for your particular CRT module. The method he chose was to use a continuity tester to find the path from a capacitor’s negative leg to the appropriate pin header. Next he used a bench supply to inject a current-limited low voltage until he saw response when probing the pins. Finding the composite-in is a similar trial and error process.

So what can you use this for? Why not make it the display for a simple video game?

Laser charged glowing display

Here’s one of the best takes on a glowing display that we’ve ever seen. Currently [H] is using his creation as a fuzzy clock, but it is certainly capable of displaying just about any messages.

The project uses a wheel of luminous paper as the display surface. This has a glow-in-the-dark quality to it which can be charged up using a bright light source. In this case a UV laser diode was used. This is perhaps the best possible source as its intensity will allow for very quick charging. The innovation here is the use of a second disk as a stencil. Look closely in the image above and you will see that the laser diode is mounted perpendicular to the display surface itself. A mirror reflects — and we believe slightly spreads — the laser dot. It then passes through a cut-out on the black wheel which is shaped as the desired character. As you can see in the video after the break, this results in a crisp and clear glowing letter.

Compare this project to the one that moves the diode itself like a plotter and we think you’ll agree this is a simpler implementation which still looks great!

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Driving an LCD character display using custom HID codes

Here’s an external display meant to help you keep track of your computer’s status. It connects via USB and is driven by a PIC microcontroller. It listens for a small set of commands, using those to implement a simple control protocol to drive the screen.

[Andrew Gehringer] designed the device around a PIC 18F2550, which offers native USB control. He’s using Microchip’s USB stack to enumerate the module as an HID device. It listens for commands 0×10 through 0×23. These clear the display, write strings to each of the four lines of the display, and switch the LCD backlight. Of course the project includes a program [Andrew] wrote to feed the display. It  has a GUI which let’s him decide what information is displayed and how it is formatted. This helper app hangs out in the system tray for easy access.

Reverse engineering Solari soft flap displays

This is a side view of the guts of a one character Solari soft flap module. This is the type of mechanical display used in some transportation hubs that have a flap for each letter. The motor turns the flaps through the alphabet until it gets to the target letter. Recently [Boz] had a client approach him who needed a custom controller for a 20-character soft flap display.

The process started out with a magnifying glass and multimeter which yielded a rather complicated hand-drawn schematic. An optical encoder is used to judge which character is currently displayed. After analyzing the output using an oscilloscope [Boz] designed a PIC based driver board which is controlling the display seen in the clip after the break.

The great thing about these displays is that they don’t use any electricity except when they change letters. This sounds like the predecessor of ePaper and makes us wonder if there are any companies developing high-contrast ePaper to replace soft-flap digits?

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Nook Simple Touch as a glider computer

Look at the beautiful screen on that Nook Simple Touch. It has a lot of advantages over other hardware when used as a glider computer running the open source XCSoar software. The contrast of the display is excellent when compared to an LCD or AOMLED. That’s quite important as gliding through the wild blue yonder often includes intense sunlight. The display is also larger than many of the Android devices that have been used for this purpose. There are a few drawbacks though. One is that unlike other Android devices, this doesn’t have a GPS module built into it. But the price point makes up for the fact that you need to source an external module yourself.

This isn’t the first time we’ve seen the device used as a navigational display. This other hack put a simple touch on a sailboat for the same direct-sunlight-readability reason. For $100, and with the ability to root the system for use as an Android device, we expect to see this to keep popping up all over the place as a simple interface for a multitude of projects.

After the break you can see a video comparing the software running on a Nook display to one on a Dell Streak 5 LCD tablet.

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Repairing a VFD driver on a car stereo

We love seeing repairs and always marvel at the ability to track down the problem. [Todd] seems to have a knack for this. He was met with a lot of adversity when trying to get the Vacuum Fluorescent Display working on his car stereo. A lot of persistence, and a little bit of taking the easier way out let him accomplish his goal.

The head unit is out of his 1994 Jeep. He knew the radio functionality still worked, but the display was completely dark. After getting it out of the dashboard he connected it to a bench supply and started probing around. He established that the data lines were still working by setting the radio to auto scan mode and testing with a multimeter. When he went to measure the cathode pins he didn’t get any reading. It seems the driver which supplies that signal is burnt out.

One easy fix would be to replace the parts from a scavenged unit. [Todd] hit the junkyard and picked up one from a Jeep that was just one model year apart from his. Alas, they weren’t exactly the same, and although he swapped out a chip (using a neat heated solder sucker) it didn’t work. In the end he simply dropped in a power resistor to use the 12V rail as a 1V at 0.1A source for the filament.

You can see his repair extravaganza in the video after the break. If you’re looking for tips on scavenging these types of displays check out this post.

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