[aprssig] APRS in-dash display (update)

Greg D ko6th.greg at gmail.com
Sat Feb 6 16:15:55 EST 2016

Hi folks,

Progress update...

Raspberry Pi connected to the car display using its built-in video 
output (no adapters).  For this experiment, I was mainly interested in 
the quality of the display.  Probably usable, but I'll let you be the 
judge...  Note: this is a "1U" DIN unit, which is rare these days; most 
cars have "double DIN" (2U) units, with a much larger display, and 
probably better inherent resolution, though you'd still be feeding it a 
VGA-quality signal.  Also note that the cable going from the Pi to the 
display was rather long (came with the backup camera); a shorter cable 
might improve the display a bit.

I also tried a rear view mirrow with a built-in display.  Result is 
considerably worse than the in-dash unit even though the physical screen 
area is larger.  Both the dash and mirror displays are fed from the same 
source, via a "Y" cable.  I may keep the new mirror even if I don't use 
the display part, because it's physically larger than the original 
(better view), and is slightly tinted for less glare.  But as a display, 
not so good.

Pi home screen on dash display: 
Pi home screen on mirror's display: 
YAAC running on Pi to the dash display: 

The Pi was definitely usable via a regular USB mouse on the small 
display, but I was sitting (not moving) in my garage at the time. On the 
road, I doubt it would be safe to use while moving unless I can get some 
sort of joy-stick like mouse for smoother control. Some of the click 
targets are really small.  More macro function buttons on the App itself 
would be nice, for common functions.

Greg  KO6TH

Greg D wrote:
> Hi folks,
> Picking up on a thread I started a while back...  Not sure if this 
> will lead to something permanent or not, but I tought I'd give it a try.
> I got access to the back of my car's in-dash unit, and the video input 
> connector.  It's meant for use with a back camera, which I currently 
> don't have (though it's on the wish list...).  Found a VGA to RCA 
> adapter box, and fired up APRSIS32 which was loaded on a small 
> laptop.  Here's the result:
> http://home.wavecable.com/~ko6th/aprs_dash_display.jpg
> http://home.wavecable.com/~ko6th/aprs_laptop.jpg
> Given the difficulty, if not questionable legality, of controlling a 
> GUI-based laptop while driving, I think the next steps need to include:
> 1.  Replace the laptop and VGA adapter with a Raspberry Pi.  VGA 
> output is built-in, also much better power draw and small size. (The 
> car is a sports car, so no room for anything bigger.)
> 2.  Replace APRSIS32 with YAAC (for Raspberry Pi compatiblity).
> 3.  Probably still need a keyboard for full control while parked, but 
> add some fixed key switches tied to keyboard shortcuts for the common 
> stuff while driving.  During the earlier exchange, Andrew figured it 
> was a "simple" matter of a Java library to bridge the swtiches to 
> keyboard shortcuts...  Hope he's right.
> 4.  The Pi will boot itself when the car turns on, but I need a way to 
> automatically safely power down the Pi when I turn the car off. Any 
> ideas on this?
> Anything else I'm missing?
> Greg  KO6TH

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