
Ask HN: Would QR codes be readable by a conference audience on the big screen? - andrewstuart
I&#x27;m trying to work out if it makes sense to display QR codes on the big screen at a conference or event, if the people in their audience could read it.<p>I suppose the answer is &quot;it depends&quot;, and in particular I&#x27;d want a very short URL.<p>Interestingly, I can easily read QR codes from 15 feet away on my PC screen by pointing my iPhone camera and zooming in.<p>But I&#x27;m interested to know if anyone has heard of this working?
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mchannon
QR codes are often misunderstood when they're on media other than paper or
computer/phone displays.

In particular, with projection-style displays like one might find at a
conference, the reflective surface of the backdrop will actually confuse a lot
of QR sensors. Any glare and what's supposed to be black will actually come
through as black with some white in it. The QR won't validate. The naked eye
can't always discern that this happens, or why this happens.

If it's a presentation given in pitch blackness, I'd say go for it.

If there are other sources of light in the room, I'd at the bare minimum do
some testing and be prepared to not put it up there.

One other consideration. If someone walked up to you on the street and said
they would offer you $10,000 if you could scan a QR code they showed you in 20
seconds, could you whip your phone out and launch/use a QR-scanning app in
that much time? I know I couldn't, and I suspect most conference attendees
couldn't either.

If all you're shooting for is a youtube video where the people at home can
scan the code, then ok, but I think QR is a solution looking for a problem
here.

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dnh44
On iOS the default camera app reads QR codes so 20 seconds would be more than
sufficient.

~~~
mchannon
For you, maybe. Half of conference attendees couldn't even launch the camera
in 40 seconds.

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LarryMade2
Hmm haven't tried it but I would think it would work, it's all about focus and
resolution, if you can take a clear shot of a PPT slide from the back row then
QR should work too...

How about this for a test - display a QR from a TV hooked to your laptop and
try to scan it from the back of your room, with the lights dimmed and at
various sizes...

I think it ultimately depends on the focusing ability of whatever QR reader
app you have.

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gus_massa
Sorry, not idea about this, but if it works it looks like a very nice subject
for a blog post in the future. (And if it doesn't work, a blog post may be
interesting too.)

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barry-cotter
Yes. I used my phone to log on to a wechat group chat Wednesday night from at
least 10m away, probably 15m. Said QR code was on a big screen.

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borplk
If possible I suggest trying a few test runs before the real session.

