Driving Three-Color E-Paper Pricetags With An Arduino

October 28, 2022 by Lewin Day 14 Comments

ePaper pricetags are becoming popular parts in the hacker community as a cheap way into tinkering with the technology. [Aaron Christophel] got his hands on a 4.4″ model with red, black, and white colors, and set about programming an ESP32 to drive the price tag instead.

The protocol the display uses was reverse-engineered by prompting the display to update via RF and monitoring the signals sent to between microcontrollers on the display’s control board. Once the protocol was understood, one of the microcontrollers could then be removed and replaced with an ESP32 for direct control. Implementing this takes some disassembly and some delicate soldering, but it’s nothing that should scare off an experienced hacker.

With the right code flashed to the ESP32, as available on Github, it’s possible to run the display directly. The hacked code does a great job driving the display, showing crisp lines and clean colors that indicate the e-Paper display is running properly.

We’ve seen [Aaron’s] work before in this area, when he hacked simpler two-color e-ink price tags. He’s also gone so far as creating entire wall displays out of salvaged displays, which is quite the sight. Video after the break.

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Flight Simulator Focuses On The Other Side Of The Cockpit Door

October 25, 2022 by Dan Maloney 22 Comments

When one thinks of getting into a flight simulator, one assumes that it’ll be from the pilot’s point of view. But this alternative flight simulator takes a different tack, by letting you live out your air travel fantasies from the passenger’s point of view.

Those of you looking for a full-motion simulation of the passenger cabin experience will be disappointed, as [Alex Shakespeare] — we assume no relation — has built a minimal airliner cabin for this simulator. That makes sense, though; ideally, an airline pilot aims to provide passengers with as dull a ride as possible. Where a flight is at its most exciting, and what [Alex] captures nicely here, is the final approach to your destination, when the airport and its surrounding environs finally come into view after a long time staring at clouds. This is done by mounting an LCD monitor outside the window of a reasonable facsimile of an airliner cabin, complete with a row of seats. A control panel that originally lived in an airliner cockpit serves to select video of approaches to airports in various exotic destinations, like Las Vegas. The video is played by a Pi Zero, while an ESP32 takes care of controlling the lights, fans, and attendant call buttons in the quite realistic-looking overhead panel. Extra points for the button that plays the Ryanair arrival jingle.

[Alex]’s simulator is impressively complete, if somewhat puzzling in conception. We don’t judge, though, and it looks like it might be fun for visitors, especially when the drinks cart comes by.

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Sight And Sound Combine In This Engaging Synthesizer Sculpture

October 23, 2022 by Dan Maloney 2 Comments

We’ll always have a soft spot for circuit sculpture projects; anything with components supported on nice tidy rows of brass wires always captures our imagination. But add to that a little bit of light and a lot of sound, and you get something like this hybrid synthesizer sculpture that really commands attention.

[Eirik Brandal] calls his creation “corwin point,” and describes it as “a generative dual voice analog synthesizer.” It’s built with a wide-open architecture that invites exploration and serves to pull the eyes — and ears — into the piece. The lowest level of the sculpture has all the “boring” digital stuff — an ESP32, the LED drivers, and the digital-to-analog converters. The next level up has the more visually interesting analog circuits, built mainly “dead-bug” style on a framework of brass wires. The user interface, mainly a series of pots and switches, lives on this level, as does a SeeedStudio WIO terminal, which is used to display a spectrum analyzer of the sounds generated.

Moving up a bit, there’s a seemingly incongruous vacuum tube overdrive along with a power amp and speaker in an acrylic enclosure. A vertical element of thick acrylic towers over all and houses the synth’s delay line, and the light pipes that snake through the sculpture pulse in time with sequencer events. The video below shows the synth in action — the music that it generates never really sounds the same twice, and sounds like nothing we’ve heard before, except perhaps briefly when we heard something like the background music from Logan’s Run.

Hats off to [Eirik] for another great-looking and great-sounding build; you may remember that his “cwymriad” caught our attention earlier this year.

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Custom Sony Camera Remote Built With ESP32

October 21, 2022 by Lewin Day 10 Comments

Whether you’re shooting video or photos, having a camera remote can really improve your productivity. No longer do you have to run back to the camera to press its tiny buttons! [Frank Zhao] is a Sony user, so decided to whip up a custom remote using the ESP32 for his Alpha camera, adding special features along the way.

The build communicates with the camera over WiFi, but can fall back to Infrared if there’s an issue with the radio link. It’s built around the M5StickC, which is a pre-built device featuring an ESP32 and a small display in a handheld form factor. It let him build the remote in half the size of the official Sony device. With limited buttons on board, though, he relies on the IMU to control many advanced features with motion gestures.

The remote enables a bunch of functionality that Sony didn’t bake into its cameras from the factory. There’s a sound-activated shutter release, dual shutter mode, and several timer-based tools including astrophotography modes. There’s also a big knob you can add for focus pulls, and a mode to reset the auto-focus when you’re frustrated that it isn’t working properly. Some of the features work better than others, as sometimes, the camera doesn’t respond to commands quickly enough. Regardless, it’s pretty neat that [Frank] has unlocked so much extra functionality with his custom $20 remote.

We’ve seen other homebrewed tools open up new creative possibilities for cameras before, too. If you’ve got your own nifty camera hacks, let us know on the tipsline!

Forearm Muscle Contraction Sensor Is Useful Component For Open Source Prosthetics

October 20, 2022 by Lewin Day 2 Comments

Being able to actuate parts of a prosthetic limb can make it much more useful. To help in this goal for partial arm or hand amputees, [TURFPTAx] has developed a sensor for detecting forearm muscle contractions.

The sensor itself is cost-effective and simple to build.

The build is part of the Open Prosthetics project, which aims to offer open designs for various types of prosthetic devices. It apes common commercial designs using a simple electromechanical system.

The build relies on magnets mounted on twelve pistons that move when the muscles contract under the skin. The pistons are sprung to allow them to follow the expansion and contractions of the muscles, and the motion of the magnets is detected by hall effect sensors. The system is bulkier than some other solutions, but has the benefit of clean output and the ability to detect the movement of several distinct muscle groups. The data is all collected by an ESP32 which is then sent wirelessly to a computer for measurement, with [TURFPTAx] using the PyGame library to plot the sensor data.

[TURFPTAx] notes that the output of the sensors would be perfect to input into a machine learning system. Video after the break.

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A digital caliper connected to a tablet computer

Custom Interface Adds USB And Wi-Fi To Digital Calipers

October 17, 2022 by Robin Kearey 26 Comments

Although old-school machinists typically prefer the mechanical vernier scale on their trusty calipers, many users nowadays buy calipers with a digital readout. These models often come with additional features like differential measurements, or a “hold” function for those situations where you have to maneuver the instrument somewhere deep inside a machine. Another useful feature is a data link that lets you log your measurements on a computer directly instead of manually entering all the values.

The VINCA-branded caliper that [Liba2k] bought has such a data link feature, which requires a USB adapter that’s sold separately. There is a micro-USB connector on the tool itself, but instead of implementing a USB interface, this is used to carry a proprietary serial protocol — a design decision that ought to be classified as a felony if you ask us. Rather than buying the official USB adapter, [Liba2k] decoded the protocol and built his own interface called VINCA Reader that can connect through either USB or Wi-Fi.

The serial format turned out to be a simple serial bus that clocks out 24 bits at a time. In order to adapt its 1.2 V signal level to the 3.3 V used by an ESP32, [Liba2k] designed a simple level shifter circuit using a handful of discrete components. The ESP can communicate with the computer through its Wi-Fi interface, for which [Liba2k] wrote a spreadsheet-like application; alternatively, an ordinary USB cable can be connected to emulate a keyboard for use with any other software.

With its added Wi-Fi feature, the VINCA Reader is actually more complete than the official USB adapter, and will probably be cheaper as well. The serial interface appears to be common to all caliper manufacturers, although many went for a more sensible connector than micro-USB. An automated readout system is particularly handy if you have to make thousands of similar measurements.

A cyclotron clock display, mounted on a wooden base. There are two stepper motors exposed on either side. There is a panel installed in the wooden base with a red button on the left, two knobs and four smaller buttons in a two by two grid on the right.

A Flipping, Perpetually-Rotating Clock

October 13, 2022 by Abe Connelly 6 Comments

Clocks are a mainstay of hackers and makers, as they provide a way to explore creative designs while still maintaining a functional aspect to the project. [Brett Oliver] follows this tradition in making a cyclotron clock that uses a perpetual rotating digit concept from a 1900s desk flip calendar.

Each digit of the clock has a rotating chamber that’s big enough to fit a group of tiles inside that have digits printed on either face. The tiles are sized and stacked in such a way that the rotation of the chamber allows the next tile to slide in front of the old one. Specific digits are revealed by rotating the chamber a number of times.

Each of the four digits positions has a 28BYJ-48 stepper motor to rotate the chamber, with each motor being driven by a ULN2003 driver module. The main microcontroller is a ESP32 WROOM, and an I2C compatible DS3231 real time clock (RTC) module keeps time. All of the motors are driven off of an LM2596 module that provides 7 V, while the ESP32 and RTC are powered from a USB connector.

The different modes and the ability to set time is done through a panel that has various buttons and knobs. The whole clock is mounted on a custom wooden base that has cutouts for the panels and cabling. [Brett Oliver] has done a great job of documentation, going into detail about the mechanics and electronics of the build. Design files, including STLs of the various components, are also available for download. Be sure to check out the video after the break.

We’ve featured a flip calendar with a similar operating principle before which clearly shows the inner workings of the mechanism.

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