问题
Is it possible to calculate the distance between an arduino bluetooth shield (BLE Shield 2.1) and cell phone? More specifically, when the cell phone is within <5 feet of the shield, I want it to perform an action. I know BLE Beacon technology is able to do this in a general sense (immediate, near, far) so I'm wondering if it is possible?
Looking through stack overflow, I've found the following answers but they are all dated:
Answer 1 Answer 2
I know that ultrasonic frequency and laser sight are both options but I am trying to keep costs low so I would prefer a way in which the distance is calculated without the use of an additional tool.
回答1:
Yes you can use it for distance calculation based on RSSI (received signal strength). You should implement iBeacon on Arduino side as stated in Eirik M answer. The most important thing in my opinion is that you have to be aware of BLE/iBeacon precision.
Please read carefully the following articles to determine if iBeacon technology fits to your needs. If so, implementation should be straight forward.
Broadcasting power and RSSI
The Beacon Experiments: Low-Energy Bluetooth Devices in Action
回答2:
If BLE beacons are good enough for you, it should be fairly easy to implement a beacon for the Arduino shield. There are a few things you need to be aware of, such as output power and antenna characteristics. I recommend to read up on beacon technology to understand how it works.
来源：https://stackoverflow.com/questions/38937888/calculate-distance-between-arduino-ble-shield-and-phone