Good proposal. Maybe it's also an idea to include glare as an
evaluation parameter and add that the gliding hat should be white,
which it often is anyway, to have the worst glare effects. It's not
always optimal to e.g. let the device 'lean back' to reduce glare as this
may reduce readability again.
By the way, I'm using a 4700 and
I must say that at the ground it sometimes is terribly difficult to read
the display, especially if you leave it in it's cradle to declare your
flight to the logger e.g. and are looking at a non-ideal angle to the
device. But in flight, when you are looking at roughly right angles to the
display, I've never had difficulties in reading the display, apart from
some glare effects.
Joop
> Hi Ian,
>
> this is definitely a great idea. This is an objective metric which
is
> very relevant for this application.
>
>
I'm using a hx4700 and agree that readability is weak unless in full
> sunlight. So I'm looking to buy a new device and readability is
> definitely the most important metric.
>
> Just a
couple of suggestions if you make the effort and post the results
> on a Wiki page:
>
> 1. describe the model as
complete as possible. Some devices come with
> different display
types. Also say if it has the bare display or an anti
> glare
foil on it.
>
> 2. I find the definition of the Test
Positions hard to remember. I
> suggest you use the angel between
sunlight and light coming from the
> display:
> Position
A is 180°
> Position B is 135°
> Position C is
90°
> Position D is 45°
> Position E is 0°
>
> Ronald
>
> Am 20.06.2011 14:37,
schrieb Ian:
>> Hi All
>>
>> I bought
an hx4700 a while back because it was reportedly one of the
>>
best of its generation with regards to sunlight readability. But quit
>> frankly once I had it installed and wired I discovered its
readability
>> during flight is still not adequate. I
previously flew with a low cost
>> GPS and then a Palm V
mounted in the cockpit which also had their
>> display
limitations so I have experienced this before. The information
>> provided by XCsoar is so useful, I would never fly without the
hx4700.
>> It is just sad that sometimes when I scan the panel
I miss some of the
>> details on the PDA.
>>
>> Now I am considering upgrading to the Dell Streak, and actively
looking
>> for alternatives, because the Dell is reported to
have significantly
>> better sunlight readability than the
hx4700. But when I read the
>> reports, it is obvious that
sunlight readability is very subjective.
>> What looks good in
the shop and during a casual walk outside does not
>> always
cut it when you mount the device is in a glider cockpit and go
>> flying.
>>
>> So I figure we should
design a means of evaluating sunlight readability
>> so we can
compare our experiences in a semi-scientific manner. I took my
>> hx4700 out into the sun yesterday and danced around with it a
while and
>> came up with the following:
>>
>>
>> PROCEDURE FOR EVALUATING SUNLIGHT READABILITY OF
A PDA DEVICE FOR
>> GLIDING PURPOSES:
>>
>> 1) Requirements:
>>
>> - PDA, PNA,
Tablet Computer, smart cell phone or other device to test,
>>
with enough battery charge.
>>
>> - XCSoar
software, loaded with terrain maps and turn points, or
>>
alternate mapping software, like Google maps.
>>
>> - An outdoor location with direct, bright sunlight.
>>
>> - Gliding sunglasses and optionally a gliding
hat or peaked cap.
>>
>>
>> 2)
Preparation:
>>
>> - Start up a XCsoar on the
device, demo mode may prove useful if it is
>> not located in
an area covered by your maps and connected to a GPS.
>>
(Otherwise use alternate mapping software like Google Maps). Make sure
>> you have some coloured features, like terrain markings, as well
as some
>> text details, like turn point or street labels,
clearly visible on the
>> screen.
>>
>> - Ensure that the PDA backlight is on full brightness and will
maintain
>> that setting for several minutes during the
evaluation.
>>
>> - Put on your sunglasses and
optionally your hat.
>>
>>
>> 3) Test
Positions:
>>
>> Take the device out into the sun
and assess it in the following 5
>> positions. In each
position the device should be held at arms length,
>> with the
screen pointing directly back at your eyes.
>>
>>
Position A: Sun shining over your shoulder such that the shadow of your
>> head falls just to one side of the device and the device is
in full
>> sunlight. If it has a reflective screen, the
reflection of the sun
>> should shine on your neck or chin,
just below your eyes.
>>
>> Position E: Hold the
device up in front of the sun so the shadow of the
>> device
blocks the sun from shining directly into your eyes. Be careful
>> not to look directly into the sun. Wearing a gliding hat or
peaked cap
>> allows you to shade your eyes from the sun with
the brim of your hat
>> while you are positioning the device.
>>
>> Position C: Rotate your arms in an ark to a
point midway between point 1
>> and point 5. Hold the device
at right angles to the sun so that it
>> shines across the
screen and small adjustments would put in in either
>> shade
or sunlight.
>>
>> Position B: Rotate your arms in
the ark to a point midway between
>> Position A and Position
C. There should be direct sunlight falling on
>> the screen.
>>
>> Position D: Rotate your arms in the ark to a
point midway between
>> Position C and Position E. The screen
should be in shadow.
>>
>> Note I have described
the positions in an order which easiest to
>> understand. Once
you know what you are doing it is very easy to go
>> through
them in alphabetic (ie positional) order.
>>
>>
>> 4) Test Procedure:
>>
>> Line up
the device in the required position and then tilt it slightly to
>> minimize the effects of reflections etc. Move it up to 15
degrees left
>> or right and/or up or down while maintaining
the relative positions of
>> the sun, your eyes and the device
until you have the best visibility.
>>
>> Hold the
position and look away at some details on the horizon for
>>
several seconds. Then glance back at the device for 2 seconds. Read some
>> black text details, like turn point labels (or street
names) on the map,
>> and then look at colour features like
terrain shading. Assign a score
>> from 5 down to 1 for the
visibility of the details. The score should be
>> similar to
the 5 to 1 score one uses to report on a radio test
>>
transmission, ie:
>>
>> 5: Clearly visible
>> 4: Some distortion, but still clearly visible.
>>
3: Significant distortion, but still visible.
>> 2. Lots of
distortion, barely visible.
>> 1. Total distortion,
information not discernible.
>>
>> Separate scores
should be assigned for black text and colour features.
>>
>> Finally make a note how high the sun is above the horizon. This
will
>> give others an indication of how bright the conditions
were during your
>> assessment.
>>
>>
>> To test the above I tried it with the following devices:
>>
>> - My HP Compaq hx4700.
>>
>> - A college's htc Desire smart phone. (Google shows that this
phone came
>> out with two models of screen, AMOLED and SLCD.
There is no definitive
>> way to determine which is installed.
The original packing does not state
>> AMOLED, which suggests
it is SLCD but the test results indicate
>> otherwise).
>>
>> - My well used Nokia 6110 Navigator cell phone.
>>
>> - My Casio black and white digital watch.
(Top of the line for a plastic
>> digital watch, but still not
an exotic watch).
>>
>>
>> I logged
these results:
>>
>> Colour visibility
>> Position A B C D E
>> hx4700 5 4 2 2 1
>> htc Desire 1 4 3 3 2
>> Nokia 6110 nav 1 3 2 2 2
>>
>> Black/white visibility
>>
Position A B C D E
>> hx4700 5 4 2 2 1
>> htc
Desire 1 4 3 3 2
>> Nokia 6110 nav 4 3 2 2 2
>>
Casio digital watch 5 5 5 5 5
>>
>>
>>
This was in sunny but winter weather in Cape Town with the sun about 35
>> to 40 deg above the horizon.
>>
>>
The most interesting comparison is Position A, with the sun shining
>> directly onto the screen. My hx4700 reads 5, but the htc is a
1. My
>> Nokia goes black and white.
>>
>> In position B both the hx4700 and the htc are clearly visible.
>>
>> The "shade" positions, C, D and E
test the strength of the back
>> lighting. The htc is better
than the others.
>>
>> Clearly the limitation of
the hx4700 is the strength of the back light
>> when it is
contrasted with a very bright sky as a background.
>>
>> As a comparison I tested my Casio black and white digital
watch. It
>> scored "5" in every position for black
text (but obviously no colour
>> scores). Interestingly when
the face was in shadow it was just as
>> legible as in
sunlight - but it looked different, as if the white
>>
background has the ability to reflect ambient light even when in shadow.
>>
>> I would appreciate it if others could
attempt the above test with
>> different devices. Please give
feedback on the devices you test as well
>> as comments and
suggestions on the test procedure. It would be very good
>> if
people could test multiple devices and give feedback on them so that
>> the relative sunlight readability of different devices can be
accessed.
>>
>> If others see the usefulness in
this idea, I am happy to post it up on a
>> wiki somewhere. We
can keep a log of test results on the same wiki.
>>
>> Thanks
>>
>> Ian
>>
>>
>>
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