Does Running An E-Paper Display At 30 FPS Destroy It?

Although e-paper displays are famous for being low-power and lasting essentially forever if not damaged physically, the recent push to drive even cheaper e-paper displays at a framerate like 30 FPS for a decent monochrome gaming experience does raise a few questions. The first being what this does to the power usage of these displays, and the second whether this will wear out the display in short order. To investigate this, [Bo Made It] set up a few experiments.

Subject of this test was a Waveshare ESP32-S3-ePaper board, which had previously been demonstrated running a Game Boy emulator at 30 FPS. With this software running, the board consumed on average about 115 mA, which would run down the device’s 400 mAh battery in about 3.5 hours. From here key was to isolate the power consumption of the display itself, with the system minus the display updates consuming about 90 mA.

Running the frame calculations for the greyscale mode without rendering to the screen pushed that up to 107.6 mA, with even in the 30 FPS greyscale mode the display thus only consuming about 7.4 mA, which is vanishingly small. Clearly the low-power claims of e-paper remain intact even at higher framerates.

As for lifespan, one datasheet gives the typical lifespan as one million updates. This would translate to about 9.3 hours at 30 FPS, though that assumes a full display refresh. Since a smart driver only updates changed pixels, obviously this will be longer, but the question is how much longer, and what will degradation look like?

After running 2.16 million frames of a custom endurance test featuring repeating patterns, some ghosting was apparent, but repeated refreshing made this go away again. This means that so far no permanent damage has been detected within the no doubt conservative limit provided by e-paper manufacturers.

It should be noted that Waveshare itself also recommends against running such high-FPS applications on their device, meaning that this is definitely one big longevity experiment. If actual damage occurs, this means that obviously this won’t be covered under any warranty.

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C64 Keycaps For Everybody

If you’ve got an MX-style keyboard and want some retro charm, you might like a recent project from [Levente Szabadkai]. It’s a set of C64-style keycaps that you can print yourself at home!

The project started as an attempt to produce a set of C64 keycaps for an Ajazz 75% keyboard layout, but [Levente] kept pushing until it developed into a universal set. The keys have C64 legends, plain legends, or blank, and work for ANSI boards from 60% to full size. There are a few ways they can be printed. — you can do two-color printing with an FDM machine, or you can print the caps alone and fill the legends with paint, either in FDM or resin.

As a part of this work, [Levente] had to obviously create the glyphs to print upon all the keycaps. He thus decided to release that as the C64 keyboard font, in fact. It’s available in TTF and OTF formats, and you can preview the font in your browser, if so desired. It includes the function key labels, the 63 PETSCII graphic font legends, and various symbols, punctuation, and selected accented letters, too.

We’ve seen lots of vintage C64 parts recreated from scratch. It’s been at the point for a while where you can build a new machine with what’s available off the shelf. They said Amiga would never die, but it’s the earlier Commodore that really lives on today…

Turning An Old Phone’s Motherboard Into An RC Plane Controller

Upcycling smartphones makes a lot of sense, especially since they contain so many components that remain useful long after their desirability as a smartphone has faded. In the case of [Mountain DS Lab], they opted to use an 8-year old Xiaomi Mi 8 phone to add long-range FPV video link and remote control functionality to an RC plane, using the phone’s LTE cellular connectivity.

The smartphone was bought used for $23, with the default Xiaomi ROM overwritten by LineageOS to get a more lightweight and up to date Android installation on it. From the video it’s clear that this phone has seen better days, with the glass back cracked and a few ugly lines running across the display. Fortunately all that is needed is the motherboard itself.

One gotcha here is that the OS checks for the display on boot and will time-out if it’s not present, potentially halting the process entirely. The workaround requires disabling the display in the device tree, which is done by modifying the boot.img file as explained in the video. Next a custom bracket for the motherboard was printed so that it could be fitted inside the target airplane.

To communicate with the avionics, a USB-to-UART adapter PCB was created with a CH340 IC on it. This was then connected together for an initial test, with the extended front camera being used as the FPV camera for the custom Android application. Using the controller via the remote LTE link worked with the flight controller, so next the airplane was assembled for initial testing.

From this point it’s all pretty standard RC airplane assembly and testing, just with the typical RF-based control and FPV link replaced with the LTE link. Unfortunately flying drones isn’t permitted in the immediate area where the creator lives, so only some taxiing was tried prior to its maiden flight at a local airstrip that will be featured in an upcoming video.

Naturally, this isn’t the first time that someone has tried this type of remote control, with the ongoing Russo-Ukraine war being a prime example of LTE-based remote control of drones. Although we do not advocate wiping out a third of a nation’s strategic bomber fleet with upcycled smartphones, ultimately this is the same technology and a good way to create an RC drone that can last more than the few kilometers eked out from a 2.4 GHz link or so. Just be prepared for the LTE link to add a few milliseconds of latency.

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JPEG-XL Is Back On The Menu

Many of the image formats we’re familiar with have been around for decades. We all know JPEG and PNG like the back of our hands, and GIF even had a bit of a resurgence when tiny annoying looping animations became cool again on social media. There has been a growth in newer formats, though, like WEBP, and AVIF, with various platforms and software companies adopting them for greater efficiency, performance, and image quality.

Amongst the new crop of formats vying for relevance is JPEG XL. It was touted as a format that improved on what JPEG could do in the lossy compression space, while also adding on a lossless mode. There were grand hopes that it would become a universal replacement for all existing raster formats on the Web. A major problem was that Google was seemingly against it, only to backflip—with the format now slated to hit the big time with renewed backing from the search giant. So what’s going on?

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Emulate The 486 In Your Browser

You might fondly remember the days of the Intel 486, but you probably don’t have one on your desk anymore. If you’d like to emulate that classic hardware, you can now do it in your browser, thanks to [Jan de Jager].

What [Jan] has built is a 100% browser-based emulator for an Intel 80486DX2-66 PC. Obviously, it’s not just a CPU that’s being emulated here—[Jan] has gone so far as to throw in the motherboard and ISA/VLB adapter card emulation necessary to make this a real and functioning computer that runs inside a solitary browser tab.

It’s all written in ES6 JavaScript. It will happily run SeaBIOS, VGA BIOS, FreeDOS 1.3, and a whole bunch of classic games, like Wolfenstein 3D, Duke Nukem, and DOOM. There’s even a control panel where you can configure the PC how you like, from storage to expansion cards and all the rest.

Once upon a time an emulator was an application you had to download and run, hoping all the while that your new machine had enough grunt to emulate the classic hardware of your desires. These days, we have endless piles of CPU cycles to throw at everything and you can do it all within a browser. Or even on a tiny microcontroller, if you feel like it!

SLAM Navigation For An Arduino Powered Car

There are plenty of “robot” projects out there that are really just a small remote control platform of some sort. We often like to think of robots of having some sort of autonomy though. [Luca Fagioli] demonstrates a great example of this with his explorer robot that uses Simultaneous Localization and Mapping (SLAM) to navigate its environment.

The robot is a built on a small plastic chassis, with one gear motor per drive wheel. Running the show is an Arduino Uno R4 Wi-Fi, paired with the Sensor Shield 5.0 and an L298N motor driver board. There’s also an HC-SR04 ultrasonic sensor module onboard, mounted atop an SG-90 servo motor so it can be panned around. The ultrasonic sensor determines the range between the robot and surrounding walls, and a map is constructed at the same time as the robot is localizing itself within it. There are also infrared sensors on the bottom of the robot for detecting tape marks on the floor for checkpointing purposes.

Often, SLAM mapping is done with advanced laser rangefinders or time of flight sensors, but there are many ways to go about it as this project demonstrates. We’ve even seen it done in a distributed manner with coordinated drones combining their efforts. Overall, it’s a highly useful technique for robot navigation and wayfinding.

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Hacking A Marine Radio Dish

Having watched some fun videos on repurposed satellite dishes on YouTube, [Melan] wanted to get in on the action, managed to source an Intellian i4 — a dish built for marine use — and set about hacking it.

[Melan] first needed to convince the antenna that it was still on a boat by using an RP2040 microcontroller and an RS-422 module to send NMEA sentences. This was necessary to tell the i4 the “heading” of the “boat”, even though [Melan] was really using the rig stationary on land. From there, a simple email to the company itself sufficed to get the Intellian software running on the antenna.

But could it be controlled without the software?. Sniff the communications between the software and the Antenna Control Unit, and decompile the code. This done, it was relatively straightforward to put together a protocol description and figure out how to command the antenna where to point simply by issuing commands for azimuth and elevation.

We’ve featured other great bits of satellite equipment before, like this truck tracker teardown from a few years ago. If you’ve got some nice equipment on the bench that listens in on (or transmits out to) birds in space, don’t hesitate to let us know on the tipsline.