The third CE project, and the first paid one, centers around a standardized header, intended for interoperability. CE provides a keyed design meant to carry common signals, and use it in the first exercise to connect a Teensy to a sensor board.
The Teensy, specifically the Teensy 3.2, isa small USB-based microcontroller board with an ARM 32 bit processor on it. It can be programmed using the Arduino IDE. The board has a fair number of pins, and I chose to populate them with female headers on the bottom. Not yet sure it was the best choice.
The first part of the project is the interface board. It has Teensy-compatible pins one one side, and the CE header on the other, thus allowing any CE header device to talk to the Teensy. I put male pins on the Teensy side, and female pins on the CE side.
The board has a jumper for selecting 3v3 or 5v on one of the CE header pins.
Here you can see the two boards together:
The final step of the design was the sensor board. This board carries a bunch of things – a digital serial-to-parallel buffer that lights up LEDs, a digital (i2c) temperature sensor, and an analog (resistive) light sensor. This was the most challenging part, as the goal was to fit a 1″ square design. I made it harder yet by using some different (larger) components than in the reference design. Some of the components are not yet populated, as I’m still trying to decide what to use.
All three boards stacked together:
