Make Use Of The 21 Spare iPads You Have Laying Around | Hacker News Reader

Make Use Of The 21 Spare iPads You Have Laying Around

engineering.madefire.com

6 pointsrwmcfa16 comments

I don't get it. Why do this with iPads, rather than the old-school way with monitors? Wouldn't that make for easier, cheaper, and higher-value? Unless they really did have 21 iPads lying around the office.

Okay, back-of-the-envelope time!

21 iPad2s is what, $850? Plus $1k worth of server to drive it? Over $9k, anyway.

This whole setup is 5376x3072 resolution, at roughly 23" by 41" of viewable area (at a novel 1.75x aspect ratio).

Nine 1920x1024 monitors would give you 5760x3072, at a more traditional 1.78x ratio. Each needs to be 13.56" x 7.75" to get the same physical size, which is to say we're talking about 17" monitors. So let's make it more visually imposing, scale it up 25% to 21" monitors. Those go for $120 each, so that's just over $1000 in monitors. You're gonna need 5 video cards, call it another $1000, and maybe those are going to go into two servers instead of one, so another $2000. At $4000 total, you're ahead at least half the price.

If you don't want to scale it up, and you're willing to go slightly lower-res, you can do 4 24" monitors, easily driven by two cards on one server. Lower cost, more-useful hardware, but lower res.

More interestingly, with either case you don't have to fight Apple's walled garden, you don't have to worry about weird RF issues or charging, and you've got general-purpose hardware that you can use for developer machines afterwards.

So, anyway, now that I've spent WAY too much time on this and should go back to work, here's my TL;DR:

Is there any reason at all that this is a good engineering approach to building a video-wall?

we used iPads b/c we're working on an app for iPads and it was a great way to instantly tell people what we're doing and it's just plain cool. most of your technical points are valid, but we wouldn't have enough power to run nine monitors at our booth. most importantly, no one would look twice at a massive monitor wall at comic-con. they're a dime a dozen and all of the big players have jumbo-tron style walls. we had loads of people comment on the iPad wall today and ask us how we did it. we even had the av guys from one of the big jumbo-tron companies come talk to us about how we built it.

Wow, that's really cool. How big of a screen did it end up being (curious about both inches and pixels)?

thanks.

pixels of iPad screens: 768 * 7 = 5376 1024 * 3 = 3072 approximate dimensions: 51.75x27.5"

Awesome! How did you make the physical board that holds all the iPads?

the booth is built with 3/4' laminated plywood, we'll have pics up soon (would already but the hotel wifi sucks.) the iPads sit on small metal L brackets fastened to the wall and are held in place heavy duty velcro. the L brackets have slots cut in them to allow the the connectors to pass through. everything is spaced and laid out such that the ipads are end-to-end horizontally and only have about 1/3" between them vertically. i'll try and get some close up pics tomorrow.

Reply on news.ycombinator.com