• Registered: 2007-12-01
  • Posts: 5

Topic: Daylight readable?

I'm thinking about hacking a Chumby into a flight display for my ultralight airplane.  It would take in NMEA GPS data, compass, EGT and CHT temps, etc from the serial port (from a separate microprocessor) and display something similar to the picture below:

http://www.pilotjournal.com/content/products/2005/mayjune/avidyne_flight_director.jpg

I actually work for the company that makes these flight displays.  Of course they cost a lot of money and aren't really set up for a UL aircraft.  So I want to do something myself, mainly because it will be fun and challenging.    I've done Linux development on the Gumstix and IMX21 platforms for a while now, so hacking this won't be a big deal.  I see that QT4 can run on it, so I'll probably go that route.  I even did a 320x240 photoshop image to see if I could fit in everything I need, and it looks usable.

So my only question is, how does the screen look in daylight?

2 Reply by njansen (edited by njansen 2007-12-02 17:52:23)

  • Registered: 2007-12-01
  • Posts: 5

Re: Daylight readable?

To answer my own question,  the Chumby LCD has a 200-250 nit brightness, and 300:1 contrast ratio (I found these numbers in a datasheet, correct me if I'm wrong on this).  For an LCD to be daylight readable, 500 nits would be absolute minimum, with 1000+ preferred.  Obviously a transflective display would be great too, but they're hard to get and are pretty expensive. 

So no, I really doubt the Chumby LCD would be readable outside.  Looks like I'll be using a Xenarc 700TSV and a PicoITX running embedded Linux hmm


Had the display been bright enough, it could have looked something like this:

http://njansen1.googlepages.com/PFD320x240.png

big_smile