display

257 Articles

New Depths For IMac Repair

March 3, 2020 by 17 Comments

There’s not much economic sense in fixing a decade-old desktop computer, especially when it’s the fancy type with the screen integrated into the body of the computer, and the screen is the thing that’s broken. Luckily for [JnsBn] aka [BEAN] the computer in question was still functional with a second monitor, so he decided to implement a cheap repair to get the screen working again by making it see-through.

The only part of the screen that was broken was the backlight, which is separate from the display unit itself. In order to view at least something on the screen without an expensive replacement part, he decided to remove the backlight altogether but leave the display unit installed. With a strip of LEDs around the edge, the screen was visible again in addition to the inner depths of the computer. After a coat of white Plasti Dip on the inside of the computer, it made for an interesting effect and made the computer’s display useful again.

While none of us, including the creator, recommend coating the inside of an iMac with Plasti Dip due to the risk of fire and/or other catastrophic failure, there’s not much to lose otherwise. Just don’t shove this one into the wall. Continue reading “New Depths For IMac Repair” →

How Many LEDs Can You Drive?

February 18, 2020 by 35 Comments

Driving more than a handful of LEDs from a microcontroller is often a feat that takes tedious wiring, tricking the processor, or a lot of extra external hardware. Charlieplexing is perhaps the most notorious of these methods, and checks two of those three boxes. This library for the Teensy 4.0 checks all three, but it can also drive a truly staggering 32,000 LEDs at one time.

The TriantaduoWS2811 library is able to drive 32 channels of LEDs from a Teensy 4.0 using only three pins and minimal processor resources. It uses the FlexIO and DMA subsystems of the i.MX RT1062, the particular ARM processor on the Teensy, to drive four external shift registers. Together, the system is able to achieve 30 frames per second on with 1,000 LEDs per channel, for a total of 32,000 LEDs. Whoah.

[Ward] aka [wramsdell] wondered what one would do with all of the horsepower of a Teensy microcontroller when he first saw its specifications, and was able to build this project to take advantage of its features. What’s surprising, though, is that it doesn’t use nearly everything the processor is capable of, so you can do other tasks at the same time as driving that giant LED display.

Camcorder Viewfinder Converted To Diminutive Vector Display

January 14, 2020 by 26 Comments

We generally cast a skeptical eye at projects that claim some kind of superlative. If you go on about the “World’s Smallest” widget, the chances are pretty good that someone will point to a yet smaller version of the same thing. But in the case of what’s touted as “The world’s smallest vector monitor”, we’re willing to take that chance.

If you’ve seen any of [Arcade Jason]’s projects before, you’ll no doubt have noticed his abiding affection for vector displays. We’re OK with that; after all, many of the best machines from the Golden Age of arcade games such as Asteroids and Tempest were based on vector graphics. None so small as the current work, though, based as it is on the CRT from an old camcorder’s viewfinder. The tube appears to be about 3/4″ (19 mm) in diameter, and while it still had some of its original circuitry, the deflection coils had to be removed. In their place, [Jason] used a ferrite toroid with two windings, one for vertical and one for horizontal. Those were driven directly by a two-channel push-pull audio amplifier to make patterns on the screen. Skip to 15:30 in the video below to see the display playing [Jerobeam Fenderson]’s “Oscilloscope Music”.

As much as we’d love to see a tiny game of Battlezone played on the diminutive display, there’s only so much it can do. Maybe an analog version of this adorable digital oscilloscope would be possible?

Continue reading “Camcorder Viewfinder Converted To Diminutive Vector Display” →

Numitron Clock Is A Tidy ’70s Throwback

December 20, 2019 by 13 Comments

As far as hacker clock builds go, the more obscure the parts involved, the better. By this yardstick, [sjm4306] has a great piece on his hands with this Numitron-based build.

The Numitron was a type of display popular in the 1970s, and often used in aircraft avionics and other high-end hardware. The display is a 7-segment type, but using filaments instead of LEDs. [sjm4306] was able to lay his hands on four of these devices, along with some bulbs to act as the digit seperator and AM/PM indicator. Due to being incandescent in nature, multiplexing wasn’t a practical option, with lower duty cycles drastically dimming the display. Instead, a 32-bit cascaded shift register was used to enable all the segments to be driven at the same time.

It’s a great build that uses some genuine original display hardware to create a clock with a compelling vintage aesthetic. This would make a great gift to a pilot from the era, or any hacker that likes the unusual display technologies of yesteryear. You can even build a Numitron watch, if you’re so inclined. Video after the break.

Continue reading “Numitron Clock Is A Tidy ’70s Throwback” →

Multimeter Display Perked Up With Nixies, LEDs, And Neon Tubes

October 30, 2019 by 6 Comments

Just because something is newer than something else doesn’t automatically make it better. Of course the opposite is also true, but when it comes to displays on bench multimeters, a fancy LCD display is no guarantee of legibility. Take the Hewlett Packard HP 3478A multimeter; the stock transflective display with its 14-segment characters is so hard to read that people usually have to add a backlight to use it.

That wasn’t good enough for [cyclotronboy], though, who chose to completely replace the stock 3478A display with Nixie tubes. He noticed that with a little modification, six IN-17 tubes just fit in the window vacated by the LCD. He sniffed out the serial data stream going to the display with a collection of XOR gates and flip-flops, which let him write the code for a PIC18F4550. The finished display adds a trio of rectangular LEDs for the + and – indicators, and an HDLO-1414 four-character alphanumeric display to indicate units and the like. And the decimal points? Tiny neon bulbs. It already looks miles better than the stock display, and with the addition of a red filter, it should look even better.

If you’re stuck with a lame LCD multimeter but Nixies don’t quite do it for you, worry not – an LED conversion is possible too.

PaperLedger: An E-Ink Cryptocurrency Ticker

August 12, 2019 by 6 Comments

For a long time it seemed like e-ink displays were outside the reach of us lowly hackers, as beyond the handful of repurposed Kindles that graced these pages, we saw precious few projects utilizing this relatively exotic display. But that’s changed over the last couple of years, and we’re thrilled to start seeing hackers bend this incredible technology to their will.

A perfect example is PaperLedger, an entry into the 2019 Hackaday Prize by [AIFanatic]. This wireless device is designed to display the current price of various cryptocurrencies on its 2.9-inch e-ink screen and provide audible price alerts with its built-in speaker. It even has a web portal where users can configure the hardware or view more in-depth price information.

The PaperLedger is based on the TTGO T5 V2.2 ESP32, but it looks like [AIFanatic] is in the process of spinning up a new board for the MIT licensed project to address some nagging issues for this particular application. Unfortunately, it doesn’t look like there are any pictures of the new board yet, but a description of the changes on the Hackaday.IO page shows that most of the work seems to be going into improving support for running on batteries.

Even if you’re not interested in cryptocurrency, the PaperLedger looks like a fantastic little e-ink monitor for pretty much anything else you’d like to keep a close eye on. The GPLv3 licensed firmware is available on the project’s GitHub page, so expanding or completely changing the device’s functionality shouldn’t be too tricky for anyone with a desire to do so and a working knowledge of C++.

We’ve seen several projects using the various TTGO boards that mate an ESP32 with a display at this point, and it looks like a great platform to check out if you want to push some data to a little WiFi screen with the minimum amount of hassle.

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Measure Your YouTube Importance

July 10, 2019 by 4 Comments

How do you hack your motivation? Do you put red marker Xs on a paper calendar every day you exercise? Do you use an egg timer to sprint through dozens of emails? Do you lock all the doors and shut off your data to write some bulletproof code? If you are [Hulk], you build a YouTube Desktop Notifier showing his YouTube subscribers and views. This is his ticket to getting off the couch to make a video about just such a device. There is something poetic about building a mechanism to monitor its own success making a feedback loop of sorts. The Hackaday.io page follows the video, so anyone who wants to build their own doesn’t have to scribble notes while pausing the video which is also posted below the break.

The hardware list is logical, starting with a NodeMCU module programmed through the Arduino IDE. Addressable 7-segment displays show the statistics in red, but you can sub in your preferred color with the back-lighting LEDs. It should be possible to share the CLK pins on the displays if you are important enough to need more digits. [Hulk] already outlined a list of improvements including switching to addressable backlights and adding daily and monthly tracking.

Monitoring online values without a computer monitor is satisfying on a level because it shows what motivates us, whether that is Bitcoin or the weather.

Continue reading “Measure Your YouTube Importance” →