Custom mouse/keyboard/serial usb AVR with nmea breakout

[skkeith]

Having a whale forced respite from sailing I decided to make good on my plans to design an interface for OpenCPN simple and robust enough for me to use from the cockpit of my I28 (while sailing solo). I don't know how the rest of you do it but there is no way I can use a mouse, keyboard, or any other traditional interface while watching out for whales and whatnot.

To this end I created the Navputter project, you can get it from:

github.com/capnkeith/navputter

This is firmware for an 8 bit AVR with USB support creating a keyboard mouse device using a 4x4 keypad. Flash it onto a USB micro controller and it will work as a USB keyboard and a mouse without drivers on Windows, Mac, or Linux. It is designed for OpenCPN, but it is a generic keyboard mouse so it does not require OpenCPN.

It has 3 modes: slow keys, fast keys, and mouse. In slow key mode, the 'arrows' inject 'arrow key + alt' key presses. In fast key mode, just arrow keys are injected. In mouse mode, the arrow keys translate into mouse movement. The other keys map to useful keypress combinations. All the keys are changeable in eeprom via the serial interface.

It has a 'radial encoder knob' like the expensive chart plotters, to zoom in and out.

Since I wanted the eeprrom field customizable I added a virtual serial interface to it also so you can edit the eeprom with a serial terminal program. This made me think Navputter might have legs beyond just a keyboard mouse driver, so I put in some NMEA parsing code and a tiny LCD display. I will accept text commands from the serial and parse the following NMEA sentences: rmc, gga, gsa, gll, gst, gsv, vtg, and zda. Look closely at the display, this is from sending $GPRMC,225446,A,4916.45,N,12311.12,W,000.5,054.7,1 91194,020.3,E*68 to /dev/ttyACM0.

I have just finished the firmware, have not yet taken it out for sea trials, so it probably needs quite a bit of tweaking to make it actually usable. If anyone is actually interested in this I can help you get going, I would appreciate any input on making this more usable...

[did-g]

Hi,
For NMEA how is it showing up on the PC ? 3 end points, kbd, mouse and serial?



Just thinking aloud but once you have something like NMEA parsing adding proprietary sentences for keys setup could be interesting.

[skkeith]

yes 3 devices. On ubuntu serial is /dev/ttyACM0.


I have nmea parsing. Adding custom sentences would work fine. Also I have custom non nmea commands via serial as well if you want that kind of thing.

[seandepagnier]

Did you try capacitive touch? I'm not sure how well it works when wet. Those keypads you have may need to be sealed to be truly waterproof.

[skkeith]

I have not built the keyboard yet just the firmware. All the keypads will need some kind of waterproofing, I think the membrane keypad should be easy enough. My plan is to try out some different designs see what works and how long it lasts.



I thought about capacitive touch, but I don't think it works well when wet. Be worth a try...