An e-ink screen mounted on a small white box is flanked by four mechanical keyboard switches. A power cable is routed from the device to a power bank that is mostly out of frame.

DIY E-Reader Has Hot Swap Mechanical Keys

October 9, 2022 by 6 Comments

In the early days of e-readers, most devices had physical buttons to turn pages and otherwise navigate the device. [bwkrayb] longed for these halcyon days before touchscreen e-readers and improved on the concept by adding mechanical keyswitches.

By using an Adafruit NeoKey 1×4 as the keyboard interface, the e-reader has four hot-swappable keyboard sockets with built-in LEDs. [bwkrayb] is hoping to use these LEDs to implement a front lighting system in a future revision of the hardware.

The 3.7″ screen displays pages after running an EPUB through ebooklib and Beautiful Soup to generate files that can be used by the Waveshare drivers. Refresh time is reportedly slow, although [bwkrayb] suspects this  might be due more to the limited power of the Raspberry Pi Zero 2 more than the display itself.

If you want to see some other open e-reader projects we’ve covered, check out the EPub-Inkplate or the Open Book Project.

A 3d printed ghost next to the base of an LED tea light that has 4 LEDs poking out and the IR receiver port and micro-USB connector showing.

A Cold Light To Warm Your Heart

October 9, 2022 by 1 Comment

Halloween is coming fast and what better way to add to your Halloween ornamentation than [Wagiminator]’s cute NeoCandle tea light simulator.

[Wagiminator] has modified a 3D printed ghost along with extending [Mark Sherman]’s light simulation code to create a cute light that’s perfect for the holiday season. The NeoCandle uses an ATtiny85 chip to power four WS2812 NeoPixel jelly bean LEDs. The device has an infrared (IR) receiver to be able to control it from a remote that speaks the NEC protocol. There is a light sensor that allows the unit to dim when it detects ambient light and the whole unit is powered off of a micro-USB connection.

The ATtiny85 have limited program flash and [Wagiminator] packs in a lot of functionality in such a small package, squeezing in a bit-banging NeoPixel driver in only 18 bytes of flash that can push out a transfer rate 762 kpbs to update the LEDs. The pseudo-random number uses a Galois linear feedback shift register and comes in at 86 bytes of flash, with the IR receiver implementation code being the largest using 234 bytes of flash. The ATtiny85 itself has 8 KB of flash memory so maybe it’s possible to push [Waginminator]’s code to even more restrictive Atmel devices in the ATtiny family.

With microcontrollers and LEDs becoming so cheap and ubiquitous, making realistic flames with them is becoming accessible, as we’ve seen with previous projects on electronic candles.

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Hackaday Links: October 9, 2022

October 9, 2022 by 16 Comments

Don’t you just hate it when you walk out of the bathroom with toilet paper stuck to your shoe? That’s a little bit like what happened when the Mars helicopter Ingenuity picked up a strange bit of debris on one of its landing pads. The foreign object was spotted on the helicopter’s down-pointing navigation camera, and looks for all the world like a streamer of toilet paper flopping around in the rotor wash. The copter eventually shed the debris, which wafted down to the Martian surface with no further incident, and without any apparent damage to the aircraft. NASA hasn’t said more about what the debris isn’t — aliens — than what it is, which of course is hard to say at this point. We’re going to go out on a limb and say it’s probably something we brought there, likely a scrap of plastic waste lost during the descent and landing phase of the mission. Or, you know, it’s getting to be close to Halloween, a time when the landscape gets magically festooned with toilet paper overnight. You never know.

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TRX-Duo Is A Red Pitaya Clone For Software Defined Radio

October 9, 2022 by 33 Comments

If you’ve noticed the TRX-DUO software-defined radio transceiver, you might have wondered how it stacks up to other choices like Red Pitaya or HackRF.  [Tech Minds] obliges with a review of the Red device in the video below.

While this unit isn’t inexpensive, it also isn’t as expensive as some of its competitors. Sure, you can pick up an RTL-SDR dongle for a fraction of the price, but then you miss out on transmitting. The device is pretty powerful compared to a cheap software defined radio:

  • Frequency: 10 kHz to 60 MHz
  • CPU: Zynq SoC with a dual-core ARM Cortex A9
  • RAM: 512 MB
  • OS: Linux
  • Connectivity: Ethernet and USB connectivity (WiFi with a dongle)
  • ADC: 16-bit at 125 MS/s (2 channels)
  • DAC: 14-bit at 125 MS/s (2 channels)

The board boots off an SD card and there are several to choose from. The video shows two different images. One has a number of applications that run on the device and will also run on a Red Pitaya. The device shows a browser menu with various options and the result is quite impressive. Using the box as a WSPR beacon, it was heard fairly well given the low output power. It was, however, able to hear the world easily.

You can get a less capable Red Pitaya model for about $100 less than the going price. However, for something comparable, you will pay more for the Red Pitaya and — depending on capabilities — perhaps a lot more, although you do get more capability for the increased price.

You can do a lot more with a transmitting SDR — having both transmit and receive opens up many new projects. Of course, canned applications are great, but if you get one of these, you are going to want to try GNU Radio.

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3D printed tea cup and saucer with the edges made out of 3d printed human teeth. Cup is sitting on a wooden table.

Relax And Have A Nice Cup Of Teeth

October 9, 2022 by 28 Comments

Halloween is just around the corner and what better way to add a little spooky decor than to 3D print [DaveMakesStuff]’s Teeth Cup.

It looks like [DaveMakesStuff] has done the equivalent of “kit bashing” by taking 3D models of a full teeth set and merging them with a tea cup. Details are pretty light but a Twitter thread (Nitter)has some clues about the process. The cup looks like it can be done in one print, support free. The smooth finish comes from bead blasting it which, as an added bonus in this case, provides the “dirty” look as the bead blaster is only normally used on nylon SLS prints.

Halloween is always a good source of inspiration for hacker projects and we’ve had many good entries from Halloween Hackfests of the past.

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RotBot Adds An Extra Dimension To 3D Printing, With A Twist

October 9, 2022 by 14 Comments

It always seemed to us that the Z-axis on a 3D printer, or pretty much any CNC machine for that matter, is criminally underused. To have the X- and Y-axes working together to make smooth planar motions while the Z-axis just sits there waiting for its big moment, which ends up just moving the print head and the bed another fraction of a millimeter from each other just doesn’t seem fair. Can’t the Z-axis have a little more fun?

Of course it can, and while non-planar 3D printing is nothing new, [Stefan] over at CNC Kitchen shows us a literal twist on the concept with this four-axis non-planar printer. For obvious reasons, it’s called the “RotBot,” and it comes via the Zurich University of Applied Sciences, where [Michael Wüthrich] and colleagues have been experimenting with different slicing strategies to make overhang printing more manageable. The hardware side of things is actually pretty intuitive, especially if you’ve ever seen an industrial waterjet cutter in action. They modified a Prusa printer by adding a rotating extension to the print head, putting the nozzle at a 45° angle to the print bed. A slip ring connects the heater and fan and allows the head to rotate 360°, with the extruder living above the swiveling head.

On the software side, the Zurich team came up with some clever workarounds to make conical slicing work using off-the-shelf slicers. As [Stefan] explains, the team used a “pre-deformation” step to warp the model and trick the slicer into generating the conical G-code. The G-code is then back-transformed in exactly the opposite process as pre-deformation before being fed to the printer. The transformation steps are done with a bit of Python code, and the results are pretty neat. Watching the four axes all work together simultaneously is quite satisfying, as are the huge overhangs with no visible means of support.

The academic paper on this is probably worth a read, and thankfully, the code for everything is all open-sourced. We’re interested to see if this catches on with the community.

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A tiny CRT showing an eye, inside a plexiglass enclosure

This Eye Is Watching You From Its Tiny CRT

October 9, 2022 by 25 Comments

The days of cathode ray tubes, or CRTs, are firmly behind us, and that’s generally a good thing. Display tubes were heavy, bulky and fragile, and needed complicated high-voltage electronics in order to work. But not all of them were actually large: miniature display tubes were also produced, for things like camcorder viewfinders, and [Tavis] from Sideburn Studios decided to turn one of those into a slightly creepy art project.

The heart of this build is a one-inch CRT that was salvaged from an RCA video camera. [Tavis] mounted the tiny tube inside an acrylic box on a 3D printed base. Inside that base sits a Raspberry Pi along with a high-voltage driver and a power management board. The Pi continuously plays a video that shows a human eye blinking and looking in various directions. Just an eye, floating in space, looking at the world around it.

The magic is briefly lost when the Pi starts up, because it then shows a microscopic version of the Pi’s standard bootup sequence, but once the thing is running it adds a weird vibe to a room. It actually looks like something you’d find in an avant-garde art exhibition — in the video (embedded below) it’s accompanied by eerie music that gives it an even more unsettling feel. Electronic eyes are always a bit scary, especially when they’re actually looking at you.

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