display

255 Articles

Mini Computer Brings Starfleet To Your Desk

June 14, 2020 by 20 Comments

It could be said that there are two types of people: those for whom the actor LeVar Burton is the host of Reading Rainbow, and those for whom he is Geordi LaForge, Chief Engineer of Star Trek TNG‘s Enterprise NCC1701-D. For those of us engineers who lie in the second camp, we can at least feel a little closer to the action thanks to a project from [Darian Johnson], a Star Trek TNG mini-computer which functions as a desktop information display.

Inside the 3D-printed case is an ESP32 version of the Adafruit Feather, talking to cloud services to pull in and aggregate the information on the TFT screen. It combines weather data, environmental sensor readings, his fitness tracker readings, and his schedule, with two useful applications. There’s a resistor colour code chart, and an LED series resistor calculator. He’s made a video showing it in operation which we’ve placed below the break, and in it, he’s captured the aesthetic of the LCARS interface perfectly. We can’t speak for a fictional future spacecraft officer, but we suspect that Geordi would be right at home with it.

We may not be able to bring you Geordi LaForge, but we can bring you a real Starfleet officer. She even shares something with LeVar Burton, in that she’s (much more) famous for something else.

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Stealing RAM For A Microcontroller From A TFT Display

May 21, 2020 by 12 Comments

PC users with long memories will recall the days when the one-megabyte barrier was  a significant problem, and the various tricks of extended and expanded memory used to mitigate it. One of them was to install a driver that mapped surplus graphics card memory as system memory when the display was in DOS text mode, and it was this that was brought to mind when we read about [Frank D]’s microcontroller implementation of Conway’s Game Of Life.

The components were those he had to hand; an STM32F030F4P6 and an RM68130 176 × 220 TFT board. The STM is not the most powerful of chips, with only 16 kB of Flash and 4 kB of RAM. The display has enough on-board memory to support 18 bits of colour information, but when it is running in eight-colour mode it only uses three of them. The 15 bits that remain are thus available to be used for other purposes, and though the arcane format in which they are read required some understanding they could be used to provide a very useful extra 38720 bytes of RAM for the microcontroller just as once happened with those DOS PC graphics cards of old. Interestingly, the same technique should work with other similar displays.

Though this isn’t a new technique by any means we can’t recall seeing it used in a microcontroller project such as this one before. We’ve brought you many Games of Life though, as well as marking John Conway’s passing earlier this year.

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How Much Is That Plotter In The Window?

May 14, 2020 by 11 Comments

We live in a strange time indeed. People who once eschewed direct interactions with fellow humans now crave it, but to limited avail. Almost every cashier at the few stores deigned essential enough to maintain operations are sealed away behind plastic shields, with the implication that the less time one spends lingering, the better. It’s enough to turn an introvert into an extrovert, at least until the barriers are gone.

We get the idea that the need to reach out and touch someone is behind [Niklas Roy]’s “Please Leave a Message”, an interactive art installation he set up in the front window of his Berlin shop. Conveniently located on a downtown street, his shop is perfectly positioned to attract foot traffic, and his display is designed to catch the eye and perhaps crack a smile. The device consists of a large wooden easel holding the guts from an old X-Y pen plotter, an Arduino and an ESP-8266, and a couple of drivers for the plotter’s steppers. Passers-by are encouraged to scan a QR code that accesses a web page served up by the ESP-8266, where they can type in a brief message. The plotter dutifully spells it out on a scroll of paper for all to see, using a very nice font that [Niklas] designed to be both readable and easily plotted. The video below shows it in action with real people; it seems to be a crowd-pleaser.

[Niklas] has been incredibly prolific, and we’ve covered many of his interactive art installations. Just search for his name and you’ll find everything from a pressure-washer dancing waters display to a plus-sized pinball machine.

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A Microcontroller Display With A Classic Twist

May 8, 2020 by 18 Comments

In a fit of lock-down-induced boredom, [Peter Z] has turned his smartphone into an LCD screen (simulation) via an Android app (German language, Google Translate link), so that a mobile device can be plugged into your favourite microcontroller and the classic HD44780 LCD look can be replicated on its screen.

It doesn’t speak standard HD44780, but rather a custom UART serial protocol, so if you’re looking for something to replace a busted LCD, this isn’t your bag. But if you are looking for a large UART terminal for debugging, with a nice aesthetic, you win.

We’d guess that a serial-to-Bluetooth converter could also be made to function, with a bit of work. The protocol is trivial too, meaning that almost any microcontroller could make use of it. All the code as well as the APK is available from the forum linked above, and there is a YouTube video of it in operation below.

The number one complaint in the comments is going to be that this doesn’t emulate a HD44780, so if that’s really what you want, read this deep-dive into the HD44780 and get hacking.

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BINA-VIEW: A Fascinating Mechanical Interference Display

April 7, 2020 by 24 Comments

[Fran Blanche] tears down this fascinating display in a video teardown, embedded below.

These displays can support up to 64 characters of the buyer’s choosing which is controlled by 6 bits, surprisingly only requiring 128 mW per bit to control; pretty power-light for its day and age. Aside from alphanumeric combinations the display also supported “color plates” which we found quite fascinating. The fully decked model would only cost you $1,206 US dollars per unit in today’s money or five rolls of toilet paper at latest street price. And that’s just one digit.

If you dig through the documents linked here, and watch her video you can get an idea of how this display works. There are six solenoids attached to rods at the rear of the device. A lamp shines through a lens onto the back of a plate assembly. Each plate is a strategically perforated grid. When the solenoids activate the selected plates tilt interfering with a stationary grid. This causes the light to be blocked in some regions only.

It seems clear why this never took off. Aligning these seems like a production nightmare compared to things like flip displays and Nixie tubes. Still, the characters have quite a lot of charm to them. We wouldn’t mind seeing a 3D printable/laser cut version of this display type. Get working!

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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.