ZSWatch: This OSHW Smart Watch Is As DIY As It Gets

We say it often, but it’s worth repeating: this is the Golden Age of making and hacking. Between powerful free and open source software, low-cost PCB production, and high resolution 3D printers that can fit on your desk, a dedicated individual has everything they need to make their dream gadget a reality. If you ever needed a reminder of this fact, just take a look at the ZSWatch.

When creator [Jakob Krantz] says he built this MIT-licensed smart watch from scratch, he means it. He designed the 4-layer main board, measuring just 36 mm across, entirely in KiCad. He wrote every line of the firmware, and even designed the 3D printable case himself. This isn’t some wearable development kit he got off of AliExpress and modified — it’s all built from the ground up, and all made available to anyone who might want to spin up their own version.

The star of the show is the nRF52833 SoC, which is paired with a circular 1.28″ 240×240 IPS TFT display. The screen doesn’t support touch, so there’s three physical buttons on the watch for navigation. Onboard sensors include a LIS2DS12 MEMS accelerometer and a MAX30101EFD capable of measuring heartrate and blood oxygen levels, and there’s even a tiny vibration motor for haptic feedback. Everything’s powered by a 220 mAh Li-Po battery that [Jakob] says is good for about two days — afterwards you can drop the watch into its matching docking station to get charged back up.

As for the software side of things, the watch tethers to a Android application over Bluetooth for Internet access and provides the expected functions such as displaying the weather, showing notifications, and controlling music playback. Oh, and it can tell the time as well. The firmware was made with extensibility in mind, and [Jakob] has provided both a sample application and some basic documentation for would-be ZSWatch developers.

While an unquestionably impressive accomplishment in its current form, [Jakob] says he’s already started work on a second version of the watch. The new V2 hardware will implement an updated SoC, touch screen, and an improved charging/programming connector. He’s also looking to replace the 3D printed case for something CNC milled for a more professional look.

The ZSWatch actually reminds us quite a bit of the Open-SmartWatch project we covered back in 2021, in that the final result looks so polished that the average person would never even take it for being DIY. We can’t say that about all the smartwatches we’ve seen over the years, but there’s no question that the state-of-the-art is moving forward for this kind of thing in the hobbyist space.

Flappy Bird Drone Edition

Ornithopters have been — mostly — the realm of science fiction. However, a paper in Advanced Intelligent Systems by researchers at Lund University proposes that flapping wings may well power the drones of the future. The wing even has mock feathers.

Birds, after all, do a great job of flying, and researchers think that part of it is because birds fold their wings during the upstroke. Mimicking this action in a robot wing has advantages. For example, changing the angle of a flapping wing can help a bird or a drone fly more slowly.

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2022 FPV Contest: Congratulations To The Winners!

We wanted to see what the Hackaday crowd was up to in first-person view tech, and you didn’t disappoint! Commercial FPV quads have become cheap enough these days that everyone and their mom got one for Christmas, so it was fantastic to see the DIY spirit in these projects. Thanks to everyone who entered.

The Winners

None of the entries do the DIY quite as thoroughly as [JP Gleyzes]’s “poor man’s FPV journey”. This is actually three hacks in one, with DIY FPV goggles made from cheap optics and 3D printed additions, a USB joystick to PPM adapter to use arbitrary controllers with an RC transmitter, and even a fully DIY Bluetooth-based controller for a popular flight simulator. [JP] has done everything but build his own drone, and all the files are there for you to use, whether you’re goal is to do it on the cheap, or to do something new.

If you want to build your own drone from scratch, though, ESP32 Drone project has you covered. At least, mostly. This build isn’t entirely finished yet, and it’s definitely got some crash-testing still in its future, but the scope and accessibility of the project is what caught our eyes. The goal is to make a lightweight indoor quad around parts we can all get easily and cheaply, completely scratch-built. This drone is meant to be controlled by a smartphone, and the coolest parts for us are the ESP_Drone and ESPStream software that run on the drone and your phone respectively. Congrats to [Jon VB]! Now get that thing in the air.

And if you’re looking for a tidy little build, [Tobias]’s Mini FPV Speed Tank doesn’t disappoint. It’s a palm-sized mini tank, but this thing hauls, and looks like a ton of fun to drive around. It uses an absolutely tiny RP2040 module, an equally tiny receiver, and a nano FPV camera and transmitter to keep it compact. The 3D-printed frame and tracks are so nice that we’re not even complaining that the FPV rig is simply rubber-banded on top of the battery. This looks like a super fun build.

Each of these three projects have won a $150 Digi-Key shopping spree to help out with parts in this, or your next project. Thanks again to Digi-Key for sponsoring!

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Machining With Electricity Hack Chat

Join us on Wednesday, January 18 at noon Pacific for the Machining with Electricity Hack Chat with Daniel Herrington!

With few exceptions, metalworking has largely been about making chips, and finding something hard enough and tough enough to cut those chips has always been the challenge. Whether it’s high-speed steel, tungsten carbide, or even little chunks of rocks like garnet or diamond, cutting metal has always used a mechanical interaction between tool and stock, often with spectacular results.

But then, some bright bulb somewhere realized that electricity could be used to remove metal from a workpiece in a controlled fashion. Whether it’s using electric sparks to erode metal — electric discharge machining (EDM) — or using what amounts to electroplating in reverse — electrochemical machining (ECM) — electrical machining methods have made previously impossible operations commonplace.

join-hack-chatWhile the technology behind ExM isn’t really that popular in the hobby machine shop yet, a lot of the equipment needed and the methods to make it all work are conceivably DIY-able. But the first step toward that is understanding how it all works, and we’re lucky enough to have Daniel Herrington stop by the Hack Chat to help us out with that. Daniel is CEO and founder of Voxel Innovations, a company that’s on the cutting edge of electrochemical machining with its pulsed ECM technology. There’s a lot to unpack, so make sure you stop by so we can all get up to speed on what’s up with using electricity to do the machining.

Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, January 18 at 12:00 PM Pacific time. If time zones have you tied up, we have a handy time zone converter.

Blinky Business Card Plays Snake And Connect Four

There’s no better way to introduce yourself than handing over a blinky PCB business card and challenging the recipient to a game of Connect Four. And if [Dennis Kaandorp] turns up early for a meeting, he can keep himself busy playing the ever popular game of Snake on his PCB business card.

The tabs are 19 mm long and 4 mm wide.
The tabs are 19 mm long and 4 mm wide.

Quite wisely, [Dennis] kept his design simple, and avoided the temptation of feature creep. His requirements were to create a minimalist, credit card sized design, with his contact details printed on the silk legend, and some blinky LED’s.

The tallest component on such a design is usually the battery holder, and he could not find one that was low-profile and cheap. Drawing inspiration from The Art of Blinky Business Cards, he used the 0.8 mm thin PCB itself as the battery holder by means of flexible arms.

Connect-Four is a two player game similar to tic-tac-toe, but played on a grid seven columns across and six rows high. This meant using 42 dual-colour LED’s, which would require a large number of GPIO pins on the micro-controller. Using a clever combination of matrix and charlieplexing techniques, he was able to reduce the GPIO count down to 13 pins, while still managing to keep the track layout simple.

It also took him some extra effort to locate dual colour, red / green LED’s with a sufficiently low forward voltage drop that could work off the reduced output resulting from the use of charlieplexing. At the heart of the business card is an ATtiny1616 micro-controller that offers enough GPIO pins for the LED matrix as well as the four push button switches.

His first batch of prototypes have given him a good insight on the pricing and revealed several deficiencies that he can improve upon the next time around. [Dennis] has shared KiCad schematic and PCB layout files for anyone looking to get inspired to design their own PCB business cards.

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A composite picture with a 3D printed cylinder with a magnet at one end held in a 3D printed housing ring on the left composite picture and a fridge buzzer board with buzzer, CR2032 battery, MCP430 microcontroller and hall effect sensor slid into a 3D printed base on the right part of the composite picture

Don’t Lose Your Cool With This Fridge Buzzer

[CarrotIndustries] wanted to add an audible warning for when the refrigerator door was left open. The result is a fridge buzzer that attaches to the inside of a fridge door and starts buzzing if the door is left ajar for too long.

The main components of the fridge buzzer consist of an MSP430G2232 low-power MCU connected to a SI7201 hall sensor switch, along with a CR2032 battery holder, push button and buzzer. The MSP430’s sleep mode is used here, consuming less than 3 µA of current which [CarrotIndustries] estimates lasting 9 years on a 235 mAh CR2032 battery.

A 3D printed housing is created so that the board slides into a flat bed, which can then be glued onto to the fridge door. The other mechanical component consists of a cylinder with a slot dug out for a magnet, where the cylinder sits in a mounting ring that’s affixed to the side of the fridge wall that the end of the door closes on. The cylinder can be finely positioned so that when the refrigerator is closed, the magnet sits right over the hall sensor of the board, allowing for sensitivity that can detect even a partial close of the fridge door.

All source code is available on [CarrotIndustries] GitHub page, including the Horizon EDA schematics and board files, the Solvespace mechanical files, and source code for the MSP430. We’ve featured an IoT fridge alarm in the past but [CarrotIndustries]’ addition is a nice, self contained, alternative.

Ring In The New Year With This Cute Cat Doorbell

What better way to ring in the new year than with [iSax Laboratories]’ charming little project that replaces a doorbell with a Maneki-Neko cat figurine to ring a physical bell?

A golden maneki-neko cat arm mechanism attached to a servo on a workbench with a hand controlling a servo motor tester that's plugged into the servo attached to the arm.

Details are unfortunately a bit light, but it looks like the Maneki-Neko cat was disassembled to allow for a small SG92R servo motor to attach to the arm pendulum mechanism. [iSax Laboratories] added wooden platform where the Maneki-Neko cat figurine is mounted along with some indicator lights, switches and the physical bell, with a cavity routed out in the base to allow for the Arduino Nano microcontroller.

[iSax Laboratories] has what looks to be an Assa Abloy Svara 23 wired answering machine, which has one of its output lines connected to the Nano to sense when a doorbell signal has come in.

The Maneki-Neko cats are cute, easily hackable figurines and we’ve featured them in the past, using them as everything from hit counters to POV displays.

Be sure to check out the demo video after the break!

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