RFID, IR or Bluetooth iBeacon range increase challenge

Hi,
I am trying to find an (affordable) solution to unlocking a door when someone comes ‘near’ it.

To be precise, they will have something on their person that can trigger the unlock before they get to the door, rather than requiring a tag, card, etc. to be tapped or presented.

I have looked at RFID solutions:
125kHz (LF) - v short range
13.56MHz (HF) - theoretically 1-3m, but most solutions describe <=40mm
860-920MHz (UHF) - theoretically up to 16m, but the receivers start to get expensive

If anyone has suggestions / experience about how to increase the effective range of the 13.56MHz systems, that would be much appreciated.

Other ideas around low power IR beacons (wearable, but have to be visible) or iBeacons would be gratefully accepted too!

Thanks, John.

Hi John,

You could try using Bluetooth, and recognising certain MAC addresses in range (up to 10m). That would also work with wearables, like a smart watch that uses Bluetooth to connect to a phone.

How does that work with your project?

Hi Josh,
It would work well - are there any low power (ie. 1+ yr battery life) BT beacons / kits around that could do the transmission so that the item can be ‘issued’ to the person rather than tied to their phone, watch, etc?

Thanks,
John.

What I’d suggest you look at is Bluetooth Low Energy (BLE) devices. The main problem is that you have to balance battery life with transmission range/frequency. A device that transmits every second will use a lot more power than one that transmits every minute/hour/so on. That’s why a phone/etc would work well, because you’re always charging them anyway. In saying that though, you could try a Flora BLE module designed to be used with the wearable Flora board, combined with a variety of batteries. There is also an iBeacon module, but I haven’t used them before so I don’t know how well it would suit you.