DIY E-Reader Folds Open Like A Book

There are plenty of lovely e-readers out on the market that come with an nice big e-paper display. There aren’t nearly as many that come with two. [Martin den Hoed] developed the Diptyx e-reader with such a design in order to better replicate the paper books of old. 

The build is based around the ESP32-S3, a powerful microcontroller which comes with the benefit of having WiFi connectivity baked in. It’s hooked up to a pair of 648×480 e-paper displays, which are installed in a fold-open housing to create the impression that one is reading a traditional book. The displays themselves are driven with custom look-up tables to allow for low-latency updates when turning pages. The firmware of the device is inspired by the epub reader from [Atomic14], and can handle different fonts and line spacing without issue. Power is from a pair of 1,500 mAh lithium-polymer cells, which should keep the device running for a good long time, and they can be charged over USB-C like any  modern gadget.

You can follow along with the project on the official website, or check it out on Crowd Supply if you’re so inclined. The project is intended to be open source, with files to be released once the design is finalized for an initial production run.

We’ve seen some great DIY e-reader builds over the years, and we’re loving the development we’re seeing in the writer deck space, too. If you’re whipping up something fun in this vein, be sure to let us know on the tipsline!

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A Compact, Browser-Based ESP32 Oscilloscope

An oscilloscope is usually the most sensitive, and arguably most versatile, tool on a hacker’s workbench, often taking billions of samples per second to produce an accurate and informative representation of a signal. This vast processing power, however, often goes well beyond the needs of the signals in question, at which point it makes sense to use a less powerful and expensive device, such as [MatAtBread]’s ESP32 oscilloscope.

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Virtual Pet Responds To WiFi

When the Tamagotchi first launched all those decades ago, it took the world by storm. It was just a bunch of simple animations on a monochrome LCD, but it had heart, and people responded to that. Modern technology is capable of so much more, so [CiferTech] set out to build a virtual pet that can sniff out WiFi networks.

The build employs an ESP32-S3, perhaps the world’s favorite microcontroller that has WiFi baked right in from the factory. It’s paired with a 240×240 TFT LCD that delivers bright, vivid colors to show the digital pet living inside. Addressable WS2812B LEDs and a simple sound engine provide further feedback on the pet’s status.

The pet has various behaviors coded in, like hunting, exploring, and resting, and moods such as “happy,” “curious,” and “bored.” For a bit of environmental reactivity, [CiferTech] also made the local WiFi environment play a role. Nearby networks can influence the “hunger, happiness, and health” of the pet.

Incidentally, if you’ve ever wondered what made the Tamagotchi tick, we’ve explored that before, too.

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Need For Speed Map IRL

When driving around in video games, whether racing games like Mario Kart or open-world games like GTA, the game often displays a mini map in the corner of the screen that shows where the vehicle is in relation to the rest of the playable area. This idea goes back well before the first in-vehicle GPS systems, and although these real-world mini maps are commonplace now, they don’t have the same feel as the mini maps from retro video games. [Garage Tinkering] set out to solve this problem, and do it on minimal hardware.

Before getting to the hardware, though, the map itself needed to be created. [Garage Tinkering] is modeling his mini map on Need For Speed: Underground 2, including layers and waypoints. Through a combination of various open information sources he was able to put together an entire map of the UK and code it for main roads, side roads, waterways, and woodlands, as well as adding in waypoints like car parks, gas/petrol stations, and train stations, and coding their colors and gradients to match that of his favorite retro racing game.

To get this huge and detailed map onto small hardware isn’t an easy task, though. He’s using an ESP32 with a built-in circular screen, which means it can’t store the whole map at once. Instead, the map is split into a grid, each associated with a latitude and longitude, and only the grids that are needed are loaded at any one time. The major concession made for the sake of the hardware was to forgo rotating the grid squares to keep the car icon pointed “up”. Rotating the grids took too much processing power and made the map updates jittery, so instead, the map stays pointed north, and the car icon rotates. This isn’t completely faithful to the game, but it looks much better on this hardware.

The last step was to actually wire it all up, get real GPS data from a receiver, and fit it into the car for real-world use. [Garage Tinkering] has a 350Z that this is going into, which is also period-correct to recreate the aesthetics of this video game. Everything works as expected and loads smoothly, which probably shouldn’t be a surprise given how much time he spent working on the programming. If you’d rather take real-world data into a video game instead of video game data into the real world, we have also seen builds that do things like take Open Street Map data into Minecraft.

Thanks to [Keith] for the tip!

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TinyCore Board Teaches Core Microcontroller Concepts

Looking for an educational microcontroller board to get you or a loved one into electronics? Consider the tinyCore – a small and nifty octagon-shaped ESP32 board by [MR. INDUSTRIES], simplified for learning yet featureful enough to offer plenty of growth, and fully open.

The tinyCore board’s octagonal shape makes it more flexible for building wearables than the vaguely rectangular boards we’re used to, and it’s got a good few onboard gadgets. Apart from already expected WiFi, BLE, and GPIOs, you get battery management, a 6DoF IMU (LSM6DSOX) in the center of the board, a micro SD card slot for all your data needs, and two QWIIC connectors. As such, you could easily turn it into, say, a smartwatch, a motion-sensitive tracker, or a controller for a small robot – there’s even a few sample projects for you to try.

You can buy one, or assemble a few yourself thanks to the open-source-ness – and, to us, the biggest factor is the [MR.INDUSTRIES] community, with documentation, examples, and people learning with this board and sharing what they make. Want a device with a big display that similarly wields a library of examples and a community? Perhaps check out the Cheap Yellow Display hacks!

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Reverse Sundial Still Tells Time

The Dutch word for sundial, zonnewijzer, can be literally translated into “Sun Pointer” according to [illusionmanager] — and he took that literal translation literally, building a reverse sundial so he would always know the precise location of our local star, even when it is occluded by clouds or the rest of the planet.

The electronics aren’t hugely complicated: an ESP32 dev board, an RTC board, and a couple of steppers. But the craftsmanship is, as usual for [illusionmanager], impeccable. You might guess that one motor controls the altitude and the other the azimuth of the LED-filament pointer (a neat find from AliExpress), but you’d be wrong.

This is more like an equatorial mount, in that the shaft the arrow spins upon is bent at a 23.5 degree angle. Through that hollow shaft a spring-steel wire connects the arrow to one stepper, to drive it through the day. The second stepper turns the shaft to keep the axis pointed correctly as Earth orbits the sun. See the demo video embedded below for full details.

Either way you can get an arrow that always points at the sun, but this is lot more elegant than an alt-az mount would have been, at the expense of a fiddlier build.  Given the existence of the orrery clock we featured from him previously, it’s safe to say that [illusionmanager] is not afraid of a fiddly build. Doing it this way also lets you read the ticks on the base just as you would a real sundial, which takes this from discussion piece to (semi) usable clock.

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A Musically-Reactive LED Christmas Tree

Regular Christmas trees don’t emit light, nor do they react to music. If you want both things in a holiday decoration, consider this build from [dbmaking]. 

An ESP32-D1 mini runs the show here. It’s hooked up to a strip of WS2812B addressable LEDs. The LED strip is placed on a wooden frame resembling the shape of a traditional Christmas tree. Ping-pong balls are then stacked inside the wooden frame such that they act as a light diffuser for the LEDs behind. The microcontroller is also hooked up to an INMP441 omnidirectional MEMS microphone module. This allows the ESP32 to detect sound and flash the LEDs in time, creating a colorful display that reacts to music. This is achieved by using the WLED web installer to set the display up in a sound reactive mode.

It’s a fun build, and we’d love to tinker around with coding more advanced visualizer effects for a build like this. We’ve seen builds that go the other way, too, by toning down excessive blinkiness in Christmas decorations.

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