Project 1 update: Teensy board

Last week I came across info about the Teensy board. From the PJRC website:

The Teensy is a complete USB-based microcontroller development system, in a very small footprint, capable of implementing many types of projects. All programming is done via the USB port. No special programmer is needed, only a standard “Mini-B” USB cable and a PC or Macintosh with a USB port.

The Teensy software is cross-platform, which is a huge advantage to
other boards, especially since I’m using a Mac Book Pro and a Linux PC.

I’ve been working on my first project, the 737 NAV1 radio. Yesterday
evening the rotary encoder could be used to tune the NAV1 standby
frequency (coarse change). Upon pushing the encoder (a CTS288 bought
from Opencockpits, part # 3T10), the tuning step changes from 100 to 5.
This allows for fine tuning the radio in steps of 0.05MHz. I have added a
pushbutton to emulate the ‘Transfer’ button on the radio, so the
frequencies are flipped between active and standby.

The wiring is done as follows:

Pins A and B from the encoder connect to Teensy pins 5 and 6. The
pushbutton connectors from the encoder connect to pin 7. The extra
pushbutton connects to pin 8. All these 4 pins have been configured as
“INPUT_PULLUP” so the microcontroller uses the builtin resistors.
Therefor, pin C from the encoder and the other pins from the 2 buttons
connect to ground directly.

All in all, I have been surprised by the ease of use of the Teensy
board and the development behind it. Paul Stoffregen from PJRC.com is
working on X-Plane integration. The concept allows for removal of Teensy
boards from the PC while X-Plane is running. Upon reconnecting the
device, the code in the Teensy board will just update any datarefs used
and continue to work!

Teensy boards can be purchased on the PJRC website at http://www.pjrc.com (US-based) or at http://www.floris.cc (based in The Netherlands).