This is mostly inspired by the wrist device worn by Captain Jack Harkness in Dr Who and Torchwood, hence the name. However the design wandered somewhat from that initial idea. This is the idea I started with:
Mine is a little different, I needed more space to do what I want, so it is a bit fatter and it doesn't actually manipulate a time vortex (whatever that is). Instead it has the following functions:
Hardware consists of a Teensy 3.2 mounted on a custom board, the Main Board, which contains circuitry for charging the attached LiPo battery when the USB port is connected, and an LSM303 to provide compass and accelerometer functions.
A second custom connector board connects to an ILI9341 touch screen. This board has a touch controller and a connector strip that matches the strip on the side of the main board.
There are some configuration settings stored on the SD card (file is hconfig.txt) which consists of the time zone, low pulse and high pulse rates. The pulse rates are used by the HRM to sound alarms if the pulse is outside that range. The time zone is used for the clock (except it isn't actually used now). The other files on the SD card are bmp files used for the picture gallery. These must be 240x320 images. All of these files are in the SDBackup directory.
Perhaps more importantly it is a development platform. There is plenty of spare capacity in the Teensy and there is still plenty of room in the assembly to add more stuff. The Main Board has connectors to unused pins on the Teensy as well. An example of adding more stuff is the heart rate monitor. I got hold of a better one which uses an I2C interface and, hardware-wise, it was simple to add the extra connections to the SDA and SCL for it, then a bit more programming and the job was done.
The assembly is a mix of leather and a 3D printed frame. Here's a demo:
Here are the details of how to build it:
All code, Eagle files etc are in github