Introduction
I have written before about Gimbal Beacons and enjoy working with them when the opportunity arises. One of the concepts that I had to learn through trial and error was the proper placement technique so that I could get the best results without any false positives. These concepts are especially important when many beacons are together within proximity. Last year I had the task of placing several beacons in adjacent conference rooms found in the same hallway. I am sharing my results with you here in hope they will be useful.
Placing the Beacons
With many adjacent conference rooms close together, my initial finding was that the various beacons kept interfering with each other and registering false positives. For example, I would arrive at two beacons at the same time and depart the one I’m genuinely interested in. Since getting the most out of these beacons requires relying on the proper events (arrival, departure, etc.) it was crucial that the events fired off properly. The name of the game with beacons is contextual location awareness, so they needed to be accurate.
Initially, I placed the beacons on the wall and then on the conference room tables for trial purposes, and I seemed to get bad results doing it this way. I used the Series 10 beacons for testing since they are cheap and perfect for this purpose. Upon investigating the design of this type of beacon, I found that the signal radiates outward from each side of the beacon (the sides with the largest surface area). Placing the beacons on the wall would radiate the signal through the walls into the other conference rooms, creating noise and polluting the results.
To solve this problem, I ended up mounting them on the ceiling using some Scotch Removable Mounting Squares. These are just double-sided mounting tape cut into squares and made it straightforward to mount these beacons. With them mounted on the ceiling toward the center of the room, the signal radiates downward and significantly reduced false positives and noise for me.
Configuring the Beacon Detection Settings
After all the beacons were mounted on the ceiling, it was time to tune the settings that trigger arrivals and departures. With the new v2.0 SDK, the beacons are detected using an abstraction called a Place. You can combine multiple beacons or just one to form a Place. The settings that trigger Place detection are as follows.
Arrival RSSI
This setting specifies the given signal strength required to set off an arrival event. Any signal that is weaker than the specified value will be ignored and thus not processed.
Departure RSSI
This setting specifies the given signal strength required to set off a departure event after an arrival has occurred. Again, any signal that is weaker than the specified value will be ignored and thus not processed.
Departure Interval (seconds)
This setting specifies the number of seconds that must go by before a beacon signal will be evaluated against for a departure. In other words, the time that must elapse where the beacon signal is weaker than the departure signal before the departure is processed.
Smoothing Window
Depending on the value chosen for this setting, the signals reported in sightings will be smoothed to make them less jumpy to not falsely trip an arrival or departure. This setting is vital when beacons are close together in proximity.
Unfortunately, there is no one size fits all approach to tuning these beacons using the above settings. Various factors will determine what the settings should be set to, such as the type of material used to construct the room or building. It’s this reason I cannot provide you with any exact settings, other than to say you’ll need to iterate on the exact settings several times to get it right. I’ve found that one of the most important settings is the smoothing window.
Testing and Further Tuning
I ended up programming the application I was working on to display all the beacons in proximity where sightings have occurred. Based on the results, I tuned the arrival and departure settings to a value that ensured I didn’t pick up an arrival from the adjacent conference room. This is the part of the process that is going to take the most amount of time to get right. However, keep in mind if your beacons aren’t as close together, this may not be as big of an issue.
You’ll need to keep making adjustments to your settings and then walking around to verify the results. I suggest patience with this process, as doing it right will pay off eventually.
Conclusion
Playing with the beacons was fun and I learned a lot when I had to install them in the conference rooms. Properly configuring them for your environment is an iterative process that will require patience. Your situation may be different from mine, and my findings presented in this article may not work well for you. Regardless, I hope you found this content useful and welcome your comments to continue the discussion.