Hi Joe,  see answers inline below for those interested.

> Whats the range of Bluetooth LE and can you adjust it?

About 50 meters max in clear line of site.  It works on a dB signal strength so anything past about 5 meters quickly fades into similar ranges (eg. -90 dB could mean you're 10 or 20 meters away, it really depends on the room you're in and the angle you're hitting the beacon with).  If you want to adjust for distance you can either do it on the device (eg. only pay attention to ranges that are < -50 dB) or you can adjust the strength of the beacon, both have pros and cons depending on what you wish to do.
> 
> I'm imagining two different scenarios here.
> In scenario 1 visitors are looking a big object - like a bus - and might be
> 3 or 4 metres away from it so we need the system to work at that range.
> In scenario two we have a narrowish gallery - say 4 metres wide with small
> objects on both sides. Visitors will get closer to the objects so we would
> need to reduce the range so that their phone tells them about the object in
> front of them - not the one behind them.

The system we use provides your location, instead of using one beacon and associating with an object we associate each beacon with a coordinate and then calculate your position based on the beacons you can see and their signal strengths (although there is a bit more to it than that).  So in short our system works for both of these scenarios.  If you're using pure proximity on the other hand then you need a lot more beacons and (due to reflections and surface noise in rooms) you're not always guaranteed that the strongest beacon signal is actually the one you're closest too.  

> As far as I can see Bluetooth LE currently works on iPhone 4S and above,
> but doesn't yet work on Android although Google say that they will support
> it in the future. Is this correct?
> If so, it looks like, at the moment most visitor's phones won't work with
> this system. Scott, how did you handle this issue in your gallery? Did you
> give out devices to visitors?

Our apps run on both iOS and Android.  On Android we currently use WiFi triangulation to get your location, on iOS this isn't possible due to the lack off API calls made available by the OS so we use bluetooth LE.  Android APIs have started supporting BTLE as of 4.3 but not all manufacturers have pushed out with updates to it yet.  We offer loan devices onsite for visitors who don't have their own.  We've worked with Nexus 7s, iPad minis and iPod touches.

Hope that helps.

Cheers,
Scott.

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