We get many questions regarding setting the distance a beacon can transmit. This might be to save battery power or to limit the distance at which a beacon can be detected.
Despite some 3rd party platforms and SDKs having settings to set distance, having such a setting is misleading. You can’t set the distance. You can set the transmitted power that affects the transmitted distance. However, as it’s radio and is susceptible to reflections and interference, there’s no way that a particular power can accurately correspond to a particular distance.
If you are detecting beacons in an app you can also use the Received Signal Strength Indicator (RSSI) to filter only those within a particular range. However, again, there’s no way to accurately map RSSI to the actual distance.
Some people ask if it’s possible to set the distance to the order of centimetres rather than metres, much like NFC. This usually isn’t possible as most beacons still transmit of the order of a metre when set to the minimum power. However, an exception to this is the Sensoro range that have two antennas that provide for what they call micro location. Their app allows you to choose between 12 power levels, the lowest of which indicates a 5cm range. However, as mentioned above, as it’s radio, such things can’t be determined accurately and our tests reported a 10cm range.
Instead if framing the questions as to whether the transmitter can be set to a minimum distance, instead consider setting the receiver to ignore longer range detections. It’s possible to use the RSSI value at the receiving app or other Bluetooth scanning device to filter out beacons that are far away. More specifically, you can ignore detections that have an RSSI less than a specific value. This can be used to only process detections of the order of centimetres.
We have an article on Choosing the Transmitted Power.