Hacker News new | past | comments | ask | show | jobs | submit login

Walled garden answer: Apple doesn't let you write an app that wakes up when a SSID becomes visible, but you can write an iOS app that wakes up and does something when an iBeacon becomes visible.

Technological answer: iBeacons allow more selectivity and precision. You can be confident that a visible iBeacon is within 30ft or so, rather than 300+ft for WiFi, and with a little calibration you can measure the distance reasonably well. WiFi can tell you "the user is in [a section of] the building", while iBeacons can tell you "the user is standing in front of exhibit X".




Some of the WiFi management tools that I've seen can locate a devices to within a 4' radius based on triangulating the signal strength. There may be others that can bring it in to an even more detailed location.

The advantage of iBeacons, of course, is that you can do this cheaply.


The walled garden answer is strictly true, but moot in this case, since you could also use region monitoring to wake up your app, and that will use SSIDs indirectly.


>You can be confident that a visible iBeacon is within 30ft or so, rather than 300+ft for WiFi, and with a little calibration you can measure the distance reasonably well.

Doesn't BLE have a range of some 150 feet+? That doesn't differ much from the range of 802.11g. Both of them have amplitude that you can measure, from which you could guess at distance (especially if you're near the same source multiple times).

Of course a store isn't going to set up a bunch of APs to notify you when you're near a display, but aside from channel overlap and ugliness technically they could. And outside of the walled garden that you mentioned, it would be just as suitable for the role it filled in this application.


iBeacon includes the device transmitting a clabirated signal transmission strength in each packet so the phone can do a calculation against the RSSI and the power the device claims to transmit at. With this information you can be much more accurate then working with a WiFi where the goal is to be loud and get as much distance in as possible.


Except that EVERYTHING interferes with a low powered btle signal. Hold your phone with an unobstructed view of an ibeacon, then put almost anything between you and it, your rssi will drop like a stone. Especially bad when it's your body between the antenna and receiver.

'iBeacon' is great for very general and very localized location finding, but you're going to have a very hard time triangulating your location very precisely in say a department store.


You are quite correct, however Apple have very sensibly been very conservative in what accuracy of distance estimation they provide to apps. The only distance values provided are: CLProximityUnknown, CLProximityImmediate, CLProximityNear, CLProximityFar. These correlate reasonably well with the type of information that can be usefully derived from RSSI (i.e., you're next to the cash register, you're in/next to the shop, you're close to the shop).


Sure but those are also highly variable. I built a test installation in a retail environment using about 15 beacons setting up four different types of zones. One of which was an attempt to do a 'tap your phone here interaction' (CLProximityImmediate trigger). The Beacon for that interaction was behind a piece of foamcore.

Now I'm not a radio engineer, it may be that it was too many beacons for the area or the general wireless soup was high but it could sometimes take 20-30 seconds to see that beacon as immediate with your phone sitting smack dab on it. Sometimes 1sec. (iOS7.0 on both ipod touch 5thgen and iphone 5 devices) . Perhaps the filtering they use just needs to be tweaked a bit.




Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact

Search: