2023 Halloween Hackfest: Flickering Pumpkin Pin Is Solidly Built

October 4, 2023 by Kristina Panos 9 Comments

Now first of all, [Steph] grants that you can already take your pick of several LED pumpkin badges out there on IO. That’s not the point. The point is that this flickering pumpkin pin is nicely-built as well as being open source.

Even though it’s fully featured — it flickers, it’s wearable, and it’s lightweight — the build couldn’t be more simple. It’s fancy through-hole LEDs and a coin cell holder, plus a tack pin to stick it through your shirt. But the final result is quite elegant thanks to clever use of PCB layering.

The first version was to get all the layers right to let the light through and embellish the jack-o-lantern’s lines with manufacturer-applied silver solder, but as [Steph] points out, it looked ‘like something a disturbed child might carve into their desk in detention’. So [Steph] enlisted [Mx. Jack Nelson], who improved the artwork.

Pretty much every component does double duty here, including the tack pin — it serves as a switch because it can hold the battery in place. The battery’s edges reflect the glowing light quite nicely around the edge of the pin. And the LEDs beneath the battery prevent it from slipping out. You can see how it goes together in the video after the break.

Continue reading “2023 Halloween Hackfest: Flickering Pumpkin Pin Is Solidly Built” →

These DIY Super Headphones Take Sound Seriously

October 1, 2023 by Donald Papp 24 Comments

[Pete Lewis] from SparkFun takes audio and comfort seriously, and recently shared details on making a customized set of Super Headphones, granting quality sound and stereo ambient passthrough, while providing hearing protection at the same time by isolating the wearer from the environment.

Such products can be purchased off the shelf (usually called some variant of “electronic hearing protection”), but every hacker knows nothing beats some DIY to get exactly the features one wants. After all, off-the-shelf solutions are focused on hearing protection, not sound quality. [Pete] also wanted features like the ability to freely adjust how much ambient sound was mixed in, as well as the ability to integrate a line-level audio source or Bluetooth input.

Early prototype of Super Headphones (click to enlarge)

On the surface the required components are straightforward, but as usual, the devil is in the details. Microphone selection, for example, required a lot of testing. A good microphone needed to be able to deal with extremely loud ambient sounds without distortion, yet still be sensitive enough to be useful. [Pete] found a good solution, but also muses that two sets of microphones (one for loud environments, and one for quieter) might be worth a try.

After several prototypes, the result is headphones that allow safe and loud band practice in a basement as easily as they provide high-quality music and situational awareness while mowing the lawn. Even so, [Pete]’s not done yet. He’s working on improving comfort by using photogrammetry to help design and 3D print custom-fitted components.

A Fossil Wrist PDA running the Overbite Gopher browser

Mobile Gopher Client Brings Fossil Wrist PDA Online

September 18, 2023 by Robin Kearey 7 Comments

Like many new technologies, smartwatches needed a few iterations before they became useful enough for the average person. Early examples were too clunky and limited to be of use to anyone but geeks who wanted to show off their “next big thing”. The 2005 Fossil Wrist PDA was a prime example: although impressively compact for its time, its limited battery life and poor feature set made it obsolete as soon as it was released. But since it ran on Palm OS, it offered plenty of opportunity for hacking: Palm expert [Cameron Kaiser] has upgraded his Wrist with internet access.

While Palm OS 4 natively supports TCP/IP networking, this component was deleted from the Wrist version to save memory. In any case, the only viable network interface would have been the USB port, which isn’t too convenient for a watch. Not to be deterred, [Cameron] worked out a way to add network support back into the Wrist: he used the IR port on a Palm m505 to send a copy of its own network drivers to the watch. This works because both devices run the same basic OS version on the same CPU type; the only drawback is that the network setup dialog doesn’t respond correctly to the Wrist’s different set of buttons. Continue reading “Mobile Gopher Client Brings Fossil Wrist PDA Online” →

Hands-Free Compass Uses Haptic Feedback

September 5, 2023 by Bryan Cockfield 15 Comments

If you’ve never experienced it before, getting turned around on a cloudy day in the woods or getting lost during an event like a snowstorm can be extremely disorienting and stressful — not to mention dangerous. In situations where travel goes outside the beaten path, it’s a good idea to have some survival gear around, including a good compass. But if you need your hands for other things, or simply don’t want to have to stop often to check a compass, you might want to try out something like this belt-mounted haptic feedback compass.

The compass is based around a Raspberry Pi Pico microcontroller and uses a ULN2803a transistor array chip to control a series of motors. The motors are mounted all along a belt using custom 3D printed clips with wires woven to each through the holes in the belt. The firmware running on the belt communicates with an Android app via USB to control each of the motor’s vibration based on the direction the wearer is traveling and their desired heading. With certain patterns, the wearer can get their correct heading based on the vibrations they feel through the belt.

While it does rely on having a functioning phone, a modern smartphone’s built-in compass doesn’t require a signal to work. We would still recommend having a good simple compass in your pack as backup if you’re going to be far off the beaten path, though. There are other ways of navigation besides by compass, map, or GPS too. Have a shot at inertial navigation if you want a challenge.

Thanks to [Peter] for the tip!

The ‘Scope Of This Kickstarter? Ten Years.

September 4, 2023 by Kristina Panos 18 Comments

It may have taken ten years to come through on this particular Kickstarter, but a promise is a promise. In late August 2023, backers who had since likely forgotten all about the project started receiving their oscilloscope watches from creator [Gabriel Anzziani]. Whatever the reason(s) for the delay, the watch looks great, and is miles ahead of the prototype pictures.

As you may have guessed, it functions as both a watch and an oscilloscope. The watch has 12- and 24-hour modes as well as an alarm and calendar, and the ‘scope has all the features of the Xprotolab dev board, which [Gabriel] also created: ‘scope, waveform generator, logic analyzer, protocol sniffer, and frequency counter.

Internally, it has an 8-bit Xmega microcontroller which features an internal PDI, and the display is a 1.28″ E ink display. When we covered this ten years ago, the screen was the type of Sharp LCD featured in the Pebble watch. [Gabriel]’s ‘scope watch features eight buttons around the edge which are user-programmable. One of [Gabriel]’s goals was for people to make their own apps.

Of course, the Kickstarter rewards are no longer available, but if you want to build your own small, digital ‘scope, check out this DIY STM32 project.

Image via the Company Formerly Known As Twitter

Bare PCB Makes A Decent Homemade Smart Watch

September 3, 2023 by Lewin Day 15 Comments

These days, we live in a post-Dick Tracy world, where you can make a phone call with your fancy wristwatch, and lots more besides. [akashv44] has gone a simpler route, designing their own from scratch with a bare PCB design.

The build is based around the ESP-12E microcontroller, providing useful wireless connectivity that lets the watch interface with the outside world. The firmware makes queries of NTP servers and Yahoo’s weather API to collect time and weather data for display. It’s also capable of interacting with Blynk relay modules for controlling other equipment, which [akashv44] uses with lights and an air conditioner. The watch uses a small OLED display and a handful of small surface-mount tactile buttons for control. Power is courtesy of a small lithium-ion pouch cell, with charging handled by a TP4056 battery management IC.

It’s a simple smartwatch, but nonetheless one that teaches all kinds of useful skills in embedded development and design. It’s also funny to think how simple it is to build. A decade ago, before the ESP8266 was released, getting wireless connectivity in such a small package was a major engineering challenge. Even the Apple Watch didn’t come out until 2015! Food for thought.

Showing pulse oximeter and color sensor combining to measure oxygen in blood and skin tone

Perfecting The Pulse Oximeter

August 7, 2023 by Orlando Hoilett 28 Comments

We’re always looking for interesting biohacks here on Hackaday, and this new research article describing a calibrated pulse oximeter for different skin tones really caught our attention.

Pulse oximeters are handy little instruments that measure your blood oxygen saturation using photoplethysmography (PPG) and are a topic we’re no strangers to here at Hackaday. Given PPG is an optical technique, it stands to reason that its accuracy could be significantly affected by skin tone and that has been a major topic of discussion recently in the medical field. Given the noted issues with pulse oximeter accuracy, these researchers endeavored to create a better pulse oximeter by quantifying skin pigmentation and using that data to offset errors in the pulse oximeter measurements. A slick idea, but we think their results leave a lot to be desired.

Their idea sounds pretty straightforward enough. They created their own hardware to measure blood oxygen saturation, a smartwatch that includes red and infrared (IR) light-emitting diodes (LED) to illuminate the tissue just below the surface of the skin, and a photosensor for measuring the amount of light that reflects off the skin. But in addition to the standard pulse oximeter hardware, they also include a TCS34725 color sensor to quantify the user’s skin tone.

So what’s the issue? Well, the researchers mentioned calibrating their color sensor to a standard commercially-available dermatology instrument just to make sure their skin pigmentation values match a gold standard, but we can’t find that data, making it a bit hard to evaluate how accurate their color sensor actually is. That’s pretty crucial to their entire premise. And ultimately, their corrected blood oxygen values don’t really seem terribly promising either. For one individual, they reduced their error from 5.44% to 0.82% which seems great! But for another user, their error actually increases from 0.99% to 6.41%. Not so great. Is the problem in their color sensor calibration? Could be.

We know from personal experience that pulse oximeters are hard, so we applaud their efforts in tackling a major problem. Maybe the Hackaday community could help them out?