As one of their colleagues was retiring, several CERN engineers got together after hours during 4 months to develop his gift: a fully open electronic watch. It is called the F*Watch and is packed with sensors: GPS, barometer, compass, accelerometer and light sensor. The microcontroller used is a 32-bit ARM Cortex-M3 SiLabs Giant Gecko which contains 128KB of RAM and 1MB of Flash. In the above picture you’ll notice a 1.28″ 128×128 pixels Sharp Memory LCD but the main board also contains a micro-USB connector for battery charging and connectivity, a micro-SD card slot, a buzzer and a vibration motor.
The watch is powered by a 500mA LiPo battery. All the tools that were used to build it are open source (FreeCAD, KiCad, GCC, openOCD, GDB) and our readers may make one by downloading all the source files located in their repository. After the break is embedded a video showing their adventure.
Continue reading “Introducing the F*Watch, a Fully Open Electronic Watch”
A couple of Harvard researchers have developed a method of using digital barometers as a touch sensor. The good news for us is that they’ve open sourced the project, including Eagle board files, firmware, and details about the materials they used.
The digital barometers were chosen for their characteristics, availability, and low-cost. The sensor uses an array of Freescale MPL115A2 chips, a MEMS Barometer designed for use in altimeters. The mass production makes them cheap (Octopart found some in single quantities for $1.71 at the time of writing). The chips are soldered onto a board which is then cast in rubber. This distributes the force while protecting the sensors. The video after the break shows them standing up to rubber hammer blows and supporting a 25 pound weight.
There are a few tricks to reading the array. The first is that the devices are designed to be used one-to-a-project so they have a fixed i2 address. A separate chip must be used to address them individually. But one it’s up and running you should be able to use it as feedback for the fingertips of that robot arm you’ve been building.
Continue reading “Building touch sensors from digital barometer chips”
[David] put together this rather nice 1-wire barometer. An MPX4115 measures the pressure while an SMD DS2438 mounted to an 8 pin DIP socket provides the 1-wire interface. The writeup includes a nice description of the board layout and wiring, making this project accessible to just about anyone with a decent tip on their soldering iron.