Simple Hack Creates an Inverted Watch Display

Before and after of a negative display watch conversion

Sometimes you have to bust out the wayback machine to find a good hack. Back in 2008, [Brian] performed this awesome negative display hack on his classic Casio G-Shock watch. The G-Shock, like most digital watches, uses a twisted nematic LCD. All Liquid Crystal Displays are made up of a layer cake of polarizers, glass, and liquid crystal. In non touchscreen displays, the top layer is a sheet of polarizing film glued down with an optical quality adhesive.

[Brian] disassembled his watch to reveal the LCD panel. Removing the glued down polarizing film can be a difficult task. Pull too hard and the thin glass layers will crack, rendering the display useless. After some patient work with an X-acto knife [Brian] was able to remove the film.

Much like the privacy monitor hack, the naked watch appeared to be off. Holding a sheet of linear polarizing film between the watch and the viewer reveals the time. If the film is rotated 90 degrees, the entire screen is color inverted. [Brian] liked the aesthetics of the inverted screen, so he glued down his polarizing film in the offset position. After reassembly, [Brian's] “customized” watch was ready to wear.

[Via Hacker News]

Hackaday Links: March 31, 2014

hackaday-links-chain

Wanting to display his Google calendars [Chris Champion] decided to mount an old monitor on the wall. The hack is his installation method which recesses both the bracket and the outlet while still following electrical code (we think).

Since we’re already on the topic. Here’s a hack-tacular project which hangs a laptop LCD as if it were a picture frame. We do really enjoy seeing the wire, which connects to the top corners and hangs from a single hook a few inches above the screen bezel. There’s something very “whatever works” about it that pleases us.

[Jaspreet] build a datalogger in an FPGA. He put together a short video demo of the project but you can find a bit more info from his repo. He’s using a DE0-Nano board which is a relatively low-cost dev board from Terasic.

Want to see what’s under the hood in the processor running a Nintendo 3DS? Who wouldn’t? [Markus] didn’t just post the die images taken through his microscope. He documented the entire disassembly and decapping process. Maybe we should have given this one its own feature?

If you’re streaming on your Ouya you definitely want a clean WiFi signal. [Michael Thompson] managed to improve his reception by adding an external antenna.

We always like to hear about the free exchange of information, especially when it comes to high-quality educational material. [Capt Todd Branchflower] teaches at the United States Air Force Academy. He wrote in to say that his ECE383 Embedded Systems II class is now available online. All the info can also be found at his Github repo.

And finally, do you remember all the noise that was made about 3D printed guns a while back? Well [Mikeasaurus] put together the .iStab. It’s a 3D printed iPhone case with an integrated folding blade…. for personal protection? Who knows. We think it should be a multitasking solution that functions as a fold-down antenna.

Smart Reflow Oven is Over-Engineered

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[Linas] reverse engineered an AMOLED HTC 800×480 screen and interfaced it with an STM32 micro-controller, along with some other components, to make a gorgeously over engineered reflow oven.

Under the hood there is a PSoC5LP PID controller to control the 800W IR heating coil and two K-type thermocouples for sensing.

The real beauty is in the relatively small STM32 chip powering the HTC AMOLED screen. The AMOLED screen is high contrast and has a wide viewing angle, giving it a clear crisp view from all front facing viewpoints. Though pushing the limits of what the STM32F429i can do, [Linas] managed to make a very nice “home-grown” user interface, complete with user configurable settings and current temperature graphs.

The user interface looks very responsive and using some clever programming, [Linas] was able to make use of the potential of the screen to provide beautiful plots and interface widgets.

[Linas] goes into quite a bit of detail about the programming involved with rendering to the screen, so be sure to check out the video after the jump.

[Read more...]

Controlling Alphanumeric LCDs With Three Wires

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The HD44780 LCD controller is the defacto way of adding a small text display to your next project. If you need a way to display a few variables, a few lines of text, or adding a small user interface to a project, odds are you’ll be using one of these parallel LCDs. These displays require at least six control lines, and if you’re using a small microcontroller or are down to your last pins, you might want to think about controlling an LCD with a shift register.

[Matteo] used the ubiquitous ’595 shift register configured as a serial to parallel converter to drive his LCD. Driving the LCD this way requires only three pins on the Arduino, [Matteo]‘s microcontroller of choice.

For the software, [Matteo] modified the stock Arduino LiquidCrystal library and put it up on his Git. Most of the functions are left untouched, but for this build the LCD can only be used in its four bit mode. That’s not a problem for 99% of the time, but if you need custom characters on your LCD you can always connect another shift register.

If you just can’t spare three pins for a display, you could squeeze this down to just two, or add a second microcontroller for a one-wire-like interface.

Controlling Alphanumeric LCDs With Two Wires

LCD

The Hitachi HD44780 LCD controller is the most common interface to all those alphanumeric LCDs out there, and there are a million and one tutorials for connecting these displays to any microcontroller imaginable. This still doesn’t mean hooking up these displays is necessarily simple, though: you still need at least four wires for the data, at least two for control signals, and power and ground lines for connecting the LCD the traditional way.

Here’s a neat trick for connecting HD44780 displays that only needs two wires. In this setup there’s only a ground and power+data wire. The interesting part of this build is using the power pin to transmit serial data with an RS-232-like format. The only difference is keeping the data line at +5 V when idle; a reasonable-sized cap keeps the display and controller alive when the master microcontroller is transmitting.

This technique does require a bit of logic on the receiving end, which a small 8-pin PIC can handle with ease. Communication between a microcontroller and this “smart” LCD is done at 2400 bps, which even the wimpiest micro can handle. All the software to make this setup work are available here, and we expect an Atmel-based version to hit the Hackaday tip line shortly.

Finding the Fix for a Dimmed 27″ iMac Screen

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Like many with a 27″ iMac, [Gerry's] been experiencing some screen brightness issues. According to him, Apple’s been largely ignoring the problem and the community’s outcry, which led to [Kaos2k] poking around inside to hack together a fix. It’s a solution clearly born from trial and error; [Kaos2k's] initial post on the issue simply recommending “applying pressure” to the panel itself, which would sometimes cause the dim screen to spring back to life.

It turns out that heat (or stress, or something) from the screen causes the solder joints to weaken on the board where a 6-pin connector hooks up, dimming the screen to eye-strain levels. Some Mac users are suing over it, because the problem tends to show up just outside of the warranty window and affects a large number of people. [Kaos2k], however, provided the much needed solution for those looking to get the fix over with: just solder the cable directly to the board. Our tipster, [Gerry], has documented his experiences over at his blog, and was kind enough to make a step-by-step video of the repair, which you can see after the break.

[Read more...]

Case Modder Builds LCD Window; Causes LSD Flashbacks

lcd-casemod

[Chris, aka Mosquito's Mods]  is well-known for some awesome PC case mods. He’s outdone himself this time with an embedded LCD panel as his case window. This use of an LCD is becoming common on arcade games and slot machines. [Chris] was inspired by an arcade game he saw at a local Dave & Buster’s. He started with an off the shelf 16″ USB LCD monitor from AOC. [Chris] then stripped off the back light, diffuser, and reflectors. Left with  the bare panel and polarizers, he then created an LCD sandwich of sorts. First a layer of 2mm acrylic. Then the LCD and panel, along with 4 strips of acrylic forming a frame around the LCD. The frame strips are in blue in the image after the break. [Read more...]