List Grid

Blogs Media Lab

Counting People in Galleries with iPod Touch

Here’s an interesting problem that came across my desk several weeks ago. Lets say you want to know exactly how many people are in a gallery at any given time. How do you do it? There are expensive people counters available, with all sorts of technology, right down to thermal imaging. There are also cheap […]

Here’s an interesting problem that came across my desk several weeks ago. Lets say you want to know exactly how many people are in a gallery at any given time. How do you do it?

There are expensive people counters available, with all sorts of technology, right down to thermal imaging. There are also cheap hand held counters, with plus and minus buttons to add and subtract people as they come and go to keep a consistent count of people in a gallery.

These cheap hand held versions are great…if you only have one entrance and exit point. What if you have multiple entrances and exits? Suddenly the hand held version falls apart, and putting cameras all over is way too expensive.

This is the issue that was put forth to me. We have an upcoming exhibition for Frida Kahlo. The gallery that the exhibition is in can only support 200 visitors at any one time. We expect more than that, especially on busy days. The kicker of course is that the gallery it’s in has two entrances, so we needed to find a way to accurately count how many people are in the gallery at any given time, and if that number goes over 200, the gallery guards would have to hold people from entering until the number dropped below 200.

I thought for sure something like this must have been made before. Surely we aren’t the only people who have ever had this problem? But in looking online I couldn’t find anything that was cost effective and would “just work”. We kept saying “if we only had two clickers that could talk to each other”.

Something interesting happened the same day I was presented with this problem. Apple announced the iPod Touch. As soon as I saw the Touch, my first thought was Art on Call and the Walker Channel. I could see all sorts of uses for both in the galleries. But after a couple hours wrestling with this given problem it hit me, why not use the iPod Touch?

The iPod Touch is handheld, has touch input, and a browser with wifi built in. All we had to do was make a simple web app for it that counted up or down. Two people could have the Touch’s, check off how many people are entering and leaving, and both be up to date on exactly how many people are in the gallery. So that’s what we did.

Here are some screen grabs of what I built. The left image is the typical display of the app. Options are simply to add or subtract a certain amount of people as they enter or leave. You’re able to reset the counter to zero in the upper right (it has a confirmation before doing so). The right image shows what happens when you go over the gallery maximum. The app also auto updates the number every 10 seconds, so the guard who has people waiting will know when the the number drops below the max value right away without needing to manually refresh.

Walker Counter Walker Counter Maxed

iPod Touch CounterMaking a web app specifically for the iPod Touch (or iPhone) turns out to be really easy. It’s just a webpage. You pretty much can do anything that is available in Safari (though there are a few inconstancies to watch out for), and there are also several special meta tags you can add specifically for these apps (for example, I turned off scaling for our web app). Apple has written up a very nice development doc on their website that I used when making this app. It includes things like screen size, font size, color, meta tags, basically everything you need to make something look nice and stylish on these devices. I’d recommend it to anyone working on apps like this. The screenshot to the left is how the iPod Touch looks with the rest of the UI around it, to give you an idea.

As far as the iPod Touch/iPhone goes, I’m very impressed. I really do think these devices are the future of museum audio tours. Well, not just audio, but video as well! There are things that need to be fixed (like the fact that you can’t get podcasts on them via wifi yet), but overall there is so much potential here, simply by having a real browser with wifi on it and supporting rich media, as well as the UI and multi-touch interface. It could very well be the Rosetta Stone of digital museum tours.

  • Wow, that is a brilliant solution. What a great hack of the system. So would your gallery guards have these iPod touches at each entrance? Would you ever roll this out on a larger scale in the museum?

  • Yes, one of these will be at each entrance to the gallery. The guards will be adding/subtracting as people enter and leave. To make it easier, we are designating one entrance to be the main entrance. The other is exit only.

    Part of the idea of building this app was to use it in the future as well for other events. Not only does it keep a current count of the capacity of a given space, but we also capture the time/date of each entrance into the gallery in the DB. Then in the future we can see the hourly/daily/weekly, etc traffic patterns for any given event we use it for.

  • We also talked about the Nintendo DS and the Nokia N800, but the iPod touch has some key advantages over either of those. The DS is cheaper, screen isn’t quite as good and the input isn’t quite as nice. the N800 has a nicer screen, but is a bit more expensive.

    The key advantage to the iPod touch, though, is battery life, and that we can use any of the battery extenders that are out there and compatible with the iPod. We won’t have any messy power cords to deal with.

  • Dafydd James says:

    That’s a great setup, though some of us unfortunately don’t have wifi throughout our galleries (yet)!

    Justin mentioned battery life – how long have the iPods worked without charging, using the browser? (Or approximately how much battery life is left at the end of the day?)

    Also have you been able to test interactive material on them yet? (eg to support an exhibition, photos, videos in a browser).

  • We still haven’t tested them in a real life setting yet, this is still mostly R&D at this point, so it’s hard to say how long the battery will last. We have also purchases some battery packs that hook on to the iPods to extend their life however, which should for sure last us through the day. I’ll be able to report on life expectancy once the show opens.

    The only interactive stuff we’ve tried on them is Art on Call and the Walker Channel, which was just browsing to those sites in Safari. They worked great. I’m pretty positive we could build something custom as a tour for these things and it would be pretty slick, but we haven’t gotten there yet.

  • Jessica Sharpe says:

    This seems like a wonderful solution. One question I have is are you able to get a total count of the number of visitors who are seeing the show on a given day? If you are “clicking” people in and then “clicking” people out will you ever know the total number who saw the show on a given day at a given time? It seems that you are using this technology to monitor access into the gallery but not to show attendance figures. Are you using some other mechanism for that?

  • Nate Solas says:

    @Jessica – We’re recording the number of visitors in a database every time it changes. It’s not currently broken up by day, but we’ll have all the data we need to do that.

    … actually, thanks for reminding me – I just checked and the script was recording waaaaay to many entries now that Brent made the iPod autorefresh. Gotta clean that up before the show opens!

  • Jen says:

    That’s a really clever solution. Just hoping the guards don’t spend too much time browsing facebook on their iPod touch!

  • Anna says:

    how long can i leave the ipod touch on for