When Your Smart Light Switches Stop Working, Build Your Own

April 30, 2023 by 14 Comments

If you want smart light switches in your house, you can buy from any one of hundreds of manufacturers. [Brian Boyle] had kitted out his home with TP Link devices, but after a few years of use, he found they all suddenly failed within a few months of each other. Decrying the state of things, he set about building his own instead.

[Brian]’s switches use the ESP32 for its handy in-built WiFi hardware. His aim was to produce smart switches that would fit neatly into standard “Decor” style switch boxes. The design uses two PCBs. One is charged with handling the mains power side of things. It carries an SPDT relay for switching AC power, and a DC power supply to run the ESP32 itself. The controller board holds the microcontroller, a Neopixel as a status indicator, and a pair of buttons — one for switching the lights on and off, the other for resetting to default settings. The physical housing is 3D printed, and looks great with the glowing status indicator in the middle of the switch.

[Brian]’s switches are triggerable via MQTT, a web interface, and the physical button onboard the device itself. Having built the devices on his own, he’ll be well-placed to troubleshoot any usability or reliability issues that crop up in the future. That’s a lot more than we can say about most smart devices on the market!

USB Borescope Lets Doctors Hone Intubation Skills On The Cheap

April 30, 2023 by 8 Comments

One of the most critical skills in emergency medicine is airway management. Without a patent airway, a patient has about four minutes to live, so doctors and paramedics put a huge amount of effort into honing their intubation skills. They have to be able to insert an endotracheal tube quickly and efficiently, without damaging sensitive structures like the vocal cords. It’s a tricky skill to master without a ton of practice.

The perfect tool to practice these skills is a video laryngoscope, but these are wildly expensive and reserved for clinical use. Luckily, with a little ingenuity and a cheap USB borescope, [Dr. Adam Blumenberg] and [Dr. Erin Falk] were able to come up with this low-cost video-assisted laryngoscopy setup to reach as many students as possible. The idea is to use a single-use laryngoscope blade, which replicates the usual tool used to visualize the patient’s vocal cords. The blade is made from clear plastic, which makes it perfect for the application. The borescope is passed through an opening in the blade and affixed to it with adhesives. A little Dremel work might be necessary to get the optical axes of the blade and the camera to line up; failing that, there’s always the option to disassemble the camera to get a better angle.

The chief advantage of this setup, aside from being cheap, is that it’s something that it’s not intended to be used on patients. Along with an airway manikin, the tricked-out borescope can sit in a conference room waiting for students to have a go. Using a large screen allows the whole group to watch the delicate procedure and learn from the mistakes of others. It may not be as detailed a simulation environment as some, but “blade time” is really what counts here.

RP2040 Gets Intellikeys Keyboard Up And Running

April 29, 2023 by 7 Comments

The Spectronic Intellikeys was an innovative keyboard-like accessibility device that used special plastic overlays that change its functionality. While a USB version of the accessible keyboard exists, it doesn’t work like a normal HID device, so it’s not plug and play as you might expect. It’s also no longer in production or supported by the manufacturer. Where industry falls down, the community steps in, right? To that end, Adafruit has built a tool for interfacing with these useful accessibility devices.

The key is the way the Intellikeys was intended to work with a computer. It was designed to download its firmware from the host machine, using special drivers that are only compatible with certain versions of Windows. That means you can’t use it with iPads or Chromebooks, for example.

To get around this, Adafruit used an RP2040 Feather configured as a USB host to talk to the Intellikeys. It queries the device, determines which overlay it currently has installed, and provides it the necessary firmware. On the other end, the Feather enumerates as a regular USB HID device. That allows it to work with a wide variety of tablets, computers, and even smartphones.

If you’ve got an Intellikeys USB device and miss using it, this could be just the thing you need. Meanwhile, you can check out some of the other interesting keyboard designs we’ve featured over the years.

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Don’t Let The Baluns Float Over Your Head

April 29, 2023 by 5 Comments

Most ham radio operators will build an antenna of some sort when they first start listening or transmitting, whether it’s a simple dipole, a beam antenna like a Yagi, or even just a random wire vertical antenna. All of these will need to be connected feedline of some sort, and in the likely event you reach for some 50-ohm coax cable you’ll also need a balun to reduce noise or unwanted radiation. Don’t be afraid of extra expenses when getting into this hobby, though, as [W6NBC] demonstrates how to construct an “ugly balun” out of the coax wire itself (PDF).

The main purpose of a balun, a contraction of “balanced-unbalanced” is to convert an unbalanced transmission line to a balanced one. However, as [W6NBC] explains, this explanation obscures much of what baluns are actually doing. In reality, they take a three-wire system (the coax) and convert it to a two-wire system (the antenna), which keeps all of the electrical noise and current on the shield wire of the coax from interfering with the desirable RF on the interior of the coax.

This might seem somewhat confusing on the surface, as coax wires only have a center conductor and a shield wire, but thanks to the skin effect which drives currents to the outside of the conductor, the shield wire effectively becomes two conductors when taking into account its inner and outer surfaces. At these high frequencies the balun is acting as a choke which keeps these two high-frequency conductors separate from one another, and keeps all the noise on the outside of the shield wire and out of the transmitter or receiver.

Granted, the world of high-frequency radio circuits can get quite complex and counter-intuitive and, as we’ve shown before, can behave quite unexpectedly when compared to DC or even mains-frequency AC. But a proper understanding of baluns and other types of transformers and the ways they interact with RF can be a powerful tool to have. We’eve even seen other hams use specialty transformers like these to make antennas out of random lengths and shapes of wire.

Continue reading “Don’t Let The Baluns Float Over Your Head” →

Hackaday Prize 2023: Tiny RC Aircraft Built Using Foam And ESP12

April 29, 2023 by 13 Comments

Once upon a time, a radio controlled plane was a hefty and complex thing. They required small nitro engines, support equipment, and relatively heavy RC electronics. Times have changed since then, as this lightweight RC build from [Ravi Butani] demonstrates.

The body of the plane is lightweight foam, and can be assembled in two ways. There’s a relatively conventional layout, using a main wing, tailplane, and rudder, or a pusher model with the main wing at the rear and a canard up front. The open hardware electronics package, which [Ravi] calls VIMANA, consists of an ESP12 module with a pair of MOSFETs to act as two independent motor drivers — allowing the plane to be flown and steered with differential thrust.

For more advanced flight control, it can also command a pair of servos to control ailerons, a rudder, canards, or elevons, depending on configuration. There’s also potential to install an IMU to set the plane up with flight stabilization routines.

Thanks to the low-cost of the VIMANA board, [Ravi] hopes it can be used in STEM education programs. He notes that it’s not limited just to aircraft, and could be used for other motorized projects such as boats and cars. We’ve featured an early version of his work before, but the project has come a long way since then.

Continue reading “Hackaday Prize 2023: Tiny RC Aircraft Built Using Foam And ESP12” →

The World’s First Agricultural Right To Repair Law

April 29, 2023 by 29 Comments

Long time readers will know that occasionally we mix up our usual subject matter with a dash of farm equipment. Usually the yellow and green variants that come from John Deere, as the agricultural manufacturer has become the poster child for all that is wrong in the fight for the right to repair. An old Deere is worth more than a nearly new one in many places, because for several years now their models have had all their parts locked down by DRM technologies such that only their own fitters can replace them. Now after a long legal fight involving many parties, the repair and parts company iFixit sound justifiably pleased as they announce the world’s first agricultural right to repair law being passed in the US state of Colorado. (Nitter)

This may sound like a small victory, and it will no doubt be followed by further rearguard actions from the industry as similar laws are tabled in other states. But in fact as we read it, with this law in place the game is de facto up for the tractor makers. Once they are required to release any access codes for the Coloradans those same codes will by extension be available to any other farmers, and though we’re guessing they won’t do this, they would be best advised to give up on the whole DRM idea and concentrate instead on making better tractors to fix their by-now-damaged brands.

It’s exciting news for everybody as it proves that right-to-repair legislation is possible, however since this applies only to agricultural machinery the battle is by no means over. Only when all machines and devices have the same protection can we truly be said to have achieved the right to repair.

We’ve reported on this story for a long time, here’s a previous piece of legislation tried in another state.

Building A WiFi Picture Frame With An EInk Display

April 29, 2023 by 6 Comments

LCD photo frames never really caught on — by emitting light, they didn’t seamlessly blend in with a home’s decor in the way printed photos do. [Sprite_tm] decided to see if a color e-Ink screen could do any better, and whipped up a WiFi-enabled photo frame using a Waveshare display.

The part in question is a 5.65-inch display with 640 x 448 resolution, and is capable of displaying seven colors. It’s not designed to display photorealistic images, so much as display simple graphics with block colors. However, with some dithering, [Sprite_tm] suspected it might do an okay job. An algorithm that uses Floyd-Steinberg diffusion and the CIEDE2000 color space takes regular RGB images and breaks them down into dithered images that are displayed using the screen’s 7 available colors.

The build relies on an ESP32-C3, which drives the display and fetches new images daily over WiFi. Thanks to the e-Ink screen, which uses zero power when not updating, the whole setup runs off two AA batteries and a Natlinear LN2266 boost converter.

There are some limitations; the screen’s color space is altogether quite limited, and images don’t look very high-fidelity in such low resolution. However, it does an able job of displaying photos for a device that was never designed to do so. It looks rather handsome all wrapped up as a 3D printed picture frame, and [Sprite_tm]’s monkey test photos are very cute.

Files are on GitHub for those that wish to roll their own. We’ve seen similar works before, like this e-Ink wall-hanging newspaper display that keeps up with the times. If you’ve got your own neat e-ink build, hit us up on the tipsline!