When adding one or more beacons to a Place, the Gimbal Platform provides the ability to customize the beacon detection on a place by place basis.
Below is an explanation of RSSI followed by some example use cases.
RSSI is measured in Decibel-milliwatts (dBm). Ignoring sources of interference (e.g. physical items in the line of sight, other sources of radio transmissions in the same range, etc.), there is an expected relationship between distance and detected RSSI. In short, the further away the mobile device is from the beacon the lower the RSSI detected by the mobile device will be. What is not intuitive is that this relationship is not on a linear scale but rather on a logarithmic scale.
The image below illustrates three implications of a logarithmic scale:
- The scale has ticks for every decrease of 10 dBM, you can see these that these ticks get closer together as you move to further away from the beacon
- Mobile Devices A and B have an RSSI difference of 10 dBM. Mobile Devices C and D also have an RSSI difference of 10 dBM. However, the Distance AB is much bigger than the Distance CD
- It’s harder to understand the precise distance of mobile devices as they get further away from the beacon. You can see that the distance of Mobile Device B from the beacon is nearly double the distance of Mobile Device A from the beacon. You can also see that the distance of Mobile Device C and Mobile Device D from the beacon is almost the same.
Distance from Beacon Approximate Gimbal RSSI Values
0-2 inches --------- -30 to -45db
2in - 3 ft --------- -46 to -60db
3ft - 20 ft --------- -61 to -75db
20ft - 35 ft --------- -76 to -85db
35ft –160 ft --------- -86 to -95 db
160 - 300 ft --------- -96 to –100db