Tell Time With A Reverse-Sundial Watch

July 27, 2017 by 23 Comments

[Xose Pérez] set out to make a sundial wristwatch by combining a magnetometer a small nylon bolt for the gnomon, but it doesn’t work like you’d think. Instead of using the magnetometer to point the sundial north, you angle the watch until the bolt’s shadow matches the white line on the PCB, and the ATmega328P computes the azimuth of the sun and determines the time thereby. To display the time he used one of those QDSP-6064 bubble displays, because sundials are retro.

His description of the project build includes a lot of fun anecdotes, like him attempting to solder the LCC connections of the HMC5883 magnetometer before giving up and making use of Seeedstudio’s PCBA service. He got 10 boards back with the ATmega and magnetometer populated while leaving the rest for [Xose] to fill in.

One fun detail of the project? You can’t tell what time it is without the sun, but you can’t read the bubble display in bright sunlight.

If you’re looking for more watch projects we’ve published, check out this wrist-controlled watch, the Chronio DIY watch, and this cool nixie-tube watch.

Hackaday Prize Entry: Health-Monitoring Flexible Smartwatch

July 15, 2017 by 17 Comments

[Nick Ames]’s Flexible Smartwatch project aims to create an Open Source smartwatch made out of a flexible, capacitive e-ink touchscreen that uses the whole surface of the band. This wraparound smartwatch displays information from the on-board pulse and blood oximetry sensor as well as the accelerometer and magnetometer, giving you a clear idea of how stressed you are about your upcoming meeting.

The display [Nick] went with is called an electrophoretic display (EPD). It’s 400×200-pixels at 115ppi with a 4″ diagonal, and can bend around a wrist. It can draw shapes in 16 shades of gray with a refresh time of under a second or B&W with a faster refresh.

The smartwatch described in [Nick]’s project would be 2.5mm thick — certainly thin enough to fit under a sleeve. We suspect that success of the form factor may hinge on [Nick]’s success in making it not look like a hospital wristband. Although this gives us the thought that a biofeedback-sensing smart wristband is probably the future of hospital stays.

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Sneak Thieves Beware: A Pi Watcheth

July 13, 2017 by 8 Comments

Ever have that strange feeling that somebody is breaking into your workshop? Well, Hackaday.io user [Kenny] has whipped up a tutorial on how to scratch that itch by turning a spare Raspberry Pi you may have kicking around into a security camera system that notifies you at a moment’s notice.

The system works like this: a Raspberry Pi 3 and connected camera module remain vigilant, constantly scanning for motion and recording video. If motion is detected, it immediately snaps and sends a picture to the user’s mobile via PushBullet, then begins recording video. If there is still movement after a few seconds, the process repeats until the area is once again devoid of motion. This also permits a two-way communication with your Pi security system, so you can check in on the live feed whenever you feel the urge.

To get this working for you — assuming that your Pi has been recently updated — setup requires setting up a PushBullet account as well as installing it on your mobile and  linking it with an API. For your Pi, you can go ahead with setting up some Python PushBullet libraries, installing FFmpeg, Pi Camera Notifier, and others. Or, install the ready-to-go image [Kenny] has prepared. He gets into the nitty-gritty of the code in his guide, so check that out or watch the tutorial video after the break.

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Shed Pounds And Inches While Binge Watching Netflix

July 13, 2017 by 33 Comments

Feel like breaking out of your streaming-induced vegetative state but can’t seem to break the binge-watching cycle? Maybe you’re a candidate for this exercise bike that controls how much Netflix you watch.

The concept behind [Roboro]’s anti-couch potato build is simple — just keep pedaling and you get to keep watching. The details are pretty simple too and start with an Arduino monitoring the signal coming from a jack thoughtfully provided by the manufacturer of his exercise bike. The frequency of the square wave is translated into a speed which a Python script on a PC reads over USB. Once a Netflix stream is started, dropping below the user-defined speed pauses the movie. The video below shows it doing its thing.

Improvements readily spring to mind, like adding a speed buffer so that pedaling faster lets you bank some streaming time and earn a rest. Maybe it could somehow integrate with these Netflix-enabled socks, or even with the Netflix and Chill button. But those sort of defeat the purpose a bit.

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Hackaday Prize Entry: Watching Out For Forest Fires

July 9, 2017 by 27 Comments

Hackaday Prize entrant [Danie Copnradie] lives in South Africa where wildfires are a major problem. Every year, humans and animals are killed, crops are destroyed, and property is lost. The FireBreakNet project aims to deploy wireless environmental sensors that alert farmers, park rangers, and emergency personnel when fires break out.

According to [Danie], firefighting services are underfunded in South Africa, with farmers and their employees having to do a lot of the work involved in firefighting with their own equipment. Having access to a network of early warning sensors would allow for faster response times, saving money and lives.

The goals of the project include a low price, easy deployment, low power consumption, physical ruggedness, and scalability. Currently, [Danie] is testing Adafruit Feather as well as Texas Instruments LaunchPad for the brains of each node, taking readings from CO2 and temperature sensors, optical air quality sensors as well as optical flame sensors.

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Watch The ClearWalker Light Up And Dip Its Toes

June 1, 2017 by 10 Comments

[Jeremy Cook]’s latest take on the Strandbeest, the ClearWalker, is ready to roll! He’s been at work on this project for a while, and walks us through the electronics and control system as well as final assembly tweaks. The ClearWalker is fully controllable and includes a pan and tilt camera as well as programmable LED segments, and even a tail.

When we last saw [Jeremy] at work on this design, it wasn’t yet functional. He showed us all the important design and assembly details that went into creating a motorized polycarbonate version of [Theo Jansen’s] classic Strandbeest design; there’s far more to the process than simply scaling parts up or down. Happily, [Jeremy] is able to show off the crystal clear beauty in his photo gallery as well as a new video, embedded below.

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Energy Harvesting Wristwatch Uses A Versatile Photodiode

May 26, 2017 by 25 Comments

There’s some interesting technology bundled into this energy harvesting wristwatch. While energy harvesting timepieces (called automatic watches) have been around for nearly 240 years, [bobricius] has used parts and methods that are more easily transferable to other projects.

Unlike early mechanical systems, this design uses the versatile BPW34 PIN photodiode (PDF warning). PIN photodiodes differ from ordinary PN diodes in that there’s a layer of undoped ‘intrinsic’ silicon separating the P and N doped layers. This reduces the utility of the diode as a rectifier, while allowing for higher quantum efficiency and switching speed.

They are typically used in the telecommunications industry, but have a number of interesting ‘off label’ applications. For example, the BPW34 can be used as a solid-state particle detector (although for detecting alpha particles you’re better off with something in a TO-5 package such as the Hamamatsu S1223-01). The fast response speed means you can send data with lasers or ambient light at high frequencies – a fun use for an LED lighting system or scrap DVD-RW laser.

Some common solar panels are essentially large PIN photodiodes. These are the brownish panels that you’ll find in a solar-powered calculator, or one of those eternally waving golden plastic neko shrines. They specifically offer excellent low-light performance, which is the basis of the energy harvesting used in this project.

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