As a musician, it’s rare to consistently recognize with the naked ear whether or not a single instrument is in tune. There are a number of electronic devices on the market to aid in this, however if you’re leading into an impromptu performance to impress your friends, using one feels about as suave as putting on your dental headgear before bed. When tuning is necessary, why not do so in a fashion that won’t cramp your style?
To help his music-major friends add an element of Bond-like flare to the chore, [dbtayl] designed a chromatic tuner that’s disguised as a pocket watch, pet-named the “pokey”. The form for the custom casing was designed in OpenSCAD and cut from aluminum stock on a home-built CNC mill. Under its bass-clef bedecked cover is the PCB which was laid out in KiCad to fit the watch’s circular cavity, then milled from a piece of copped-clad board. The board contains the NXP Cortex M3 which acts as the tuner’s brain and runs an FFT (Fast Fourier Transform) that uses a microphone to match the dominant pitch it hears to the closest note. Five blue surface-mount LEDs on the side indicate how sharp or flat the note is, with the center being true.
[dbtayl’s] juxtaposition of circuitry in something that is so heavily associated with mechanical function is a clever play on our familiarity. You can see a test video of the trinket in action below:
Whether you own a pocket watch, want to own one, or just plain think they’re cool, [Fran’s] video on setting and regulating pocket watches provides a comprehensive overview on these beautiful works of mechanical art. After addressing the advantages and disadvantages between stem, lever, and key set watches, [Fran] cracks open her 1928 Illinois to reveal the internals and to demonstrate how to adjust the regulator.
Though she doesn’t dive into a full teardown, there’s plenty of identification and explanation of parts along the way. To slow her watch down a tad, [Fran] needed to turn a very tiny set screw about a quarter of a turn counterclockwise, slowing down the period: an adjustment that requires a fine jewelers screwdriver, a delicate touch, and a lot of patience. Results aren’t immediately discernible, either. It takes a day or two to observe whether the watch now keeps accurate time.
Stick around for the video after the jump, which also includes an in-depth look at a 1904 Elgin watch, its regulator and other key components.
Until recently, watches have been entirely mechanical where each wheel, gear, and mechanism representing a milestone in our understanding of precision manufacturing and timekeeping.
Today it is nearly impossible to find watchmakers to service or repair vintage mechanical pocket and wristwatches, so we have to do it ourselves. Learn to repair vintage mechanical watches. You can do this and we’ll show you how.
[Frank] wanted a classy way of telling the time, so he built up a LED Pocket Watch. The watch features 132 LEDs for displaying the time, two buttons to activate and change modes, a vibration motor, and a buzzer.
It’s controlled by a picoPower ATmega645P, which has enough pins to drive the array of LEDs, an internal real time clock, and low power consumption. The device is housed behind laser cut acrylic face, and sits in a 3D printed case.
To power the device, [Frank] used a rechargeable lithium coin cell battery. The charging circuitry is based on a MCP73831, which is an easy to integrate charge control IC. A USB connector is used to provide power to the board.
One of the bigger challenges of the design is driving the large array of LEDs. [Frank] uses Charlieplexing to group the LEDs and reduce the number of pins required. Another trick he used was offsetting the ISP header pins. This allows for programming the AVR without soldering a connector to the board.
[Frank]’s Instructables write-up is very detailed, and includes explanations of the schematic, PCB layout, software design, and case design. It’s a good read that details his design decisions.
After the break, watch [Frank]’s video overview of the project.
[moris_zen] found himself with a hand full of Li-Ion batteries and no good way to see what their capacities were. He built a this unique tester really quick to get the job done. He’s using off the shelf components and a cheap pocket watch which he bought in Taiwan for $1. You hook the circuit up to your battery, click the button and the watch starts working. When it stops, you multiply that number by .38 to get your amp/hour results. Sure, he could have just used a counter, but this is an interesting approach. All he needs to do now is make a nice container to hide all of the circuitry. How could he change the circuit to make the end multiplication unnecessary?