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AndersG
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Daylight viewable 5" screen for Pi?

Thu Jun 21, 2018 12:20 pm

Dunno if this belongs here, in "projects" or "hardware", but here it goes...

I am looking at replacing a navigator with a Pi, running OpenCPN. This will be on a sailboat, so power is limited. Reference is an old Garmin 420s. It has a 4" screen and draws 600mA with enough backlight to be viewable in daylight. A 5" screen would be pretty optimal. I use paper charts for backup and planning anyway.

I am looking for suggestions for a screen. HDMI seems to be an unnecessary overkill so I am looking at the various boards out there that interface more or less directly. Preferably leaving enough ports/pins for stuff like GPS, AIS, Sounder etc.

There are several interface boards available: The Pi Kippah, MCIB-15 and others. Can anyone suggest a screen/board combo that would work in this scenario, without having to write the driver myself and that could be sealed so that will survive a splash?
Anders G

PiGraham
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Re: Daylight viewable 5" screen for Pi?

Thu Jun 21, 2018 5:07 pm

Could you use a Kindle?Daylight readable but slow refresh.


These videos suggest possibilities but lack relevant details.

https://www.youtube.com/watch?v=TliNY5a7X4M

https://www.youtube.com/watch?v=gh-DIcZ6BA4

douglas5962
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Re: Daylight viewable 5" screen for Pi?

Thu Jun 21, 2018 5:26 pm

You may want to take a look at Comfile, they have a IP65 rated panel PC that's based on the Compute Module 3... It may be too big but it's worth considering since it has a built in real time clock and multiple USB ports for connecting to your GPS.

http://comfiletech.com/new-products/cpi ... -panel-pc/

W. H. Heydt
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Re: Daylight viewable 5" screen for Pi?

Thu Jun 21, 2018 5:35 pm

Is 5" your upper limit? You might consider the RPF 7" screen that connects to the DSI port.

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AndersG
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Re: Daylight viewable 5" screen for Pi?

Thu Jun 21, 2018 6:48 pm

Well, my thought was that current consumption increases with screen size. I did look at the Pi 7" screen, but have not seen it IRL. I have heard that it has a very low brightness though, but I have not seen any firm figures on cd/m2 for the "7 pi

I have mailed comfile asking details of power draw. The price seems OK. After all, a dedicated chartplotter costs 500-1000€
Anders G

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Imperf3kt
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Re: Daylight viewable 5" screen for Pi?

Thu Jun 21, 2018 9:36 pm

Would a 5.9" 1080p screen for $99USD be acceptable?
The manga screen 2 has the best contrast ratio on such small screens that I know of.
Stephen Hawking, rest in peace.
8 January 1942 – 14 March 2018

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AndersG
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Re: Daylight viewable 5" screen for Pi?

Fri Jun 22, 2018 12:36 pm

Interesting! There is a 4.8 inch one as well, but capacitive could be a problem. Water spray an such.

So what sbout all those cards that supposedly allow you to hook up just about any tft?
Anders G

PiGraham
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Re: Daylight viewable 5" screen for Pi?

Fri Jun 22, 2018 6:24 pm

AndersG wrote:
Thu Jun 21, 2018 6:48 pm
Well, my thought was that current consumption increases with screen size. I did look at the Pi 7" screen, but have not seen it IRL. I have heard that it has a very low brightness though, but I have not seen any firm figures on cd/m2 for the "7 pi

I have mailed comfile asking details of power draw. The price seems OK. After all, a dedicated chartplotter costs 500-1000€
The 7" is listed as 400 nits (Cd/m2) which is not great for sunlight readability.
A screen’s brightness, or luminance, is measured by number of nits. Nits is more scientifically referred to as Candelas (candlepower!) per meter squared (Cd/m2), but display manufacturers generally list nits in their spec sheets. The higher the nit spec, the brighter the display.
Most indoor LCD displays are 300 to 350 nits, which look sharp and clear in a dimly lit room. For an equally vivid picture, an outdoor display must be at least 400 nits—but plan to install it in a shadowed, protected location, like under an eave, or facing east with only morning sun. If you’re going to place a screen by a pool, in the middle of a plaza, or facing west, it must be at least 700 nits to appear bright and readable in direct sunlight.

https://mytechdecisions.com/video/under ... -displays/
[ETA]
Actually 400 nits may not be too bad. The best screen I have used in sunlight is a Dell Latitude rugged tablet. It's not easy to read in gull sun but I could just about make it out. It's far better than any other laptop or tablet I have seen. I don't have an iPad.
You can definitely view this screen outdoors. Emitting up to 525 nits, the Latitude 7212 beats the 287-nit category average and shines far brighter than the 376-nit ThinkPad X1 and the 396-nit Surface Pro. The iPad Pro gets even brighter, at 555 nits. Although the Latitude's screen gets really bright, its colors still darken when viewed from 30 degrees to the left and right, though the display is legible and brighter than many other laptops and tablets at those angles

https://www.laptopmag.com/reviews/lapto ... eme-tablet
Are you worrying about power consumption? High brightness screens are going to burn through batteries much faster than a Pi alone would do. The low power option is some sort of eInk or transflective LCD

douglas5962
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Re: Daylight viewable 5" screen for Pi?

Sat Jun 23, 2018 8:17 pm

I'm not sure if you found this yet, but the Comfile 7" unit draws 6 watts. There's more information in the online "manual" here:

http://comfilewiki.co.kr/en/doku.php?id=comfilepi:index

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AndersG
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Re: Daylight viewable 5" screen for Pi?

Sat Jun 23, 2018 8:52 pm

Yes. 6W would be acceptable.
Anders G

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