Stylish OLED Watch Uses Accelerometer Instead of Buttons

A few days ago [Andrew] contacted us to offer his help for the design of the mooltipass project case. While introducing himself, he casually mentioned his OLED watch that you can see above.

The watch is based on the low-power MSP430F microcontroller from Texas Instruments. It can consume as little as 1.5uA while maintaining a real-time clock and monitoring interrupts. It also uses ferroelectric RAM, which doesn’t need any power to retain its memory contents. That means there’s no need to set the time again if you remove the CR2016 battery that powers the watch.

[Andrew] chose an 0.96″ OLED display that only consumes up to 7mA. He also included an accelerometer that allows him to interact with the watch through its single and double tap detecting feature. He modeled his PCB using EagleCAD and the whole assembly using Sketchup. Most of the components were soldered in his reflow (toaster) oven. The final result is a mere 8.8mm thick and looks very professional in our opinion.

Persistence of Vision Planetary Map

POV planetary map

Looking at the looping GIF above you’re probably thinking, oh, another hard drive POV setup… Well… Not quite.

This is one of [Dev's] latest projects, and it is a planetary map that shows the angular positions of all 8 of the major celestial bodies from any given date between 1800 and 2050. It’s also capable of showing analogue clock hands, the phases of the moon, and other simple graphics.

The main unit is a hard disk, but [Dev] milled off many of the features on it to give it a more exposed, purpose-built look. He designed the LED bearing PCB from scratch using EagleCAD, which sits on the back of the drive, with the spindle poking through. It has 8 rings of 5 surface mounted LEDs, which shine through opaque plastic diffuser rings that he printed using Shapeways — they feature small recesses to fit snugly on the board over the LEDs. On the top level is a 1mm thick black disc of some unknown material that [Dev] had sitting around, which now has 8 holes machined into it in the exact position of the LEDs.

A Cortex-M0 drives the LEDs using an LPCXpresso board which allows the LEDs to sit across only one byte of a hardware I/O port. On the software end, each rotation of the disk is segmented into three hundred and sixty 1 degree slices. This system allows him to achieve a circular resolution of 8×360 pixels at 25 frames per second. Not bad for a persistence of vision device!

Stick around after the break to see the rather entertaining demo video of the device.

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Script lets you import Eagle boards for use in FreeCAD


[Christian Aurich] wanted to use his Eagle CAD circuit board design in a proper CAD program in order to design enclosures. There are already a few options along these lines, but they didn’t quite fit his needs so he developed a script to import Eagle boards into FreeCAD. The script is packaged as a python macro for FreeCAD.

In describing the shortcomings of what’s already out there [Christian] does mention the use of EagleUp to model boards in Google SketchUp. But he feels the way the data is produced by SketchUp makes these models work well with 3D printing, but says they’re not easy to use with mechanical design CAD software. He also feels that the photo-realistic renderings are useless when developing enclosures.

It’s worth mentioning that this approach is only possible because CadSoft’s migration to XML makes it dead simple to get at the data.

CadSoft’s EAGLE 6 hits beta and packs goodies

Version 6 of the popular schematic and PCB layout software EAGLE is now in beta testing. The most notable change is the migration to XML file formats that we looked at last month.

[PT] didn’t waste any time getting his hands on the software and giving it a thorough test drive. The image seen above shows the files of a MintyBoost. It’s impossible to make out at this resolution, but it is indeed spitting out human-readable (well maybe) XML in the windows below instead of the ‘no trespassing’ binaries they used to use.

Earlier today when working on a feature we had to jump on a different computer that had EAGLE installed in order to look at a .SCH file. We wonder if someone will put out a rendering package that can parse the new format and spit out a quick PNG? At the very least, we expect to see some useful hacks for part replacement or pin swapping. It shouldn’t be too hard to poke around and figure out what happens when changing some of the stored values. Got anything in mind that you can do by editing these by hand?

Oh, we almost forgot! The biggest benefit you get from this is the increased version control compatiblity since programs like git will be able to perform diff functions on the files.

PCB milling tutorial

[Juan Jose Chong] put together a set of videos and a PDF guide to milling printed circuit boards. You’ll find the pair of videos, totaling about twenty-two minutes, embedded after the break. In them, [Jaun] details the techniques used by the IEEE chapter at Texas Tech University to mill PCBs instead of using the traditional method of etching them. We’ve long been a fan of milled PCBs and often dream about the day we can retire the old iron we use for the toner transfer method.

In the tutorial, IsoPro is the software used to control the mill. The CAM files from a PCB design program are imported – they can come from many different programs including EagleCAD. A few setup steps let the operator configure the resolution necessary to mill the correct tolerance and from there the paths that outline each trace are calculated in software. In order to facilitate double-sided boards a reference hole is drilled in the copper clad board to accept a post on the mill table. Tape down the substrate with some foil tape, set the depth of the end mill bit, and let the machine do its thing. [Juan's] video illustrates how quickly this can produce a rather complicated board, finishing in around 20 minutes.

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Update: Adafruit Eagle library, now with Arduino

Adafruit Industries has just added an Arduino shield footprint to their EagleCAD library. If you don’t know, the Arduino headers use non-standard pin spacing. Learn to deal with it, there’s too many Arduino shields in production to have any hope for a change in the future. This footprint should make it a lot easier to design your own boards. If you use this package make sure you’re getting the library from their github, they’ve been adding parts regularly. Setting up version control will make sure you always have the latest libraries.

[Thanks pt]

Adafruit Eagle library

We love it when a PCB comes out right the first time. We’re careful enough with our designs that if something is wrong it’s usually a footprint problem, like we picked the wrong package for the components. Adafruit is helping to make the design process easier by sharing their Eagle library. Like the Eagle library version control we saw earlier in the month, this library is housed on github making it easy to stay up-to-date. The library includes many components (switches, crystals, IC’s, etc.), and fixes some prolbem-footprints, like 0805 surface mount pads.