Update: Check out this innovative Real Time Location Bluetooth Low Energy Application built with Symphony Link: www.AirFinder.com
Let’s tell a little (fictitious) Internet of Things, electrical engineering story, shall we? Two friends, both engineers and fitness fanatics, recently opened a business with multiple obstacle courses in the parking lot of an old warehouse. They’re looking to capitalize on the fitness trend while offering a fun outing of tire flips, trampolines, and rope climbs for an afternoon.
But they know a key selling point they’re missing is data. People want to know how far they traveled, top speed, how long it took to complete, and how they did against other top competitors. They know they need a wireless tracking device to place on contestants, so they set out to build it themselves.
Being engineers, they want to know what to expect if they use Bluetooth Low Energy (also know as Bluetoo LE or Bluetooth 4.0) as the wireless technology to send and receive data. Here is the scenario and Bluetooth LE range expectations:
Antenna: The antenna is installed inside of the block-wall building on the second floor.
Receiver: Data will be transmitted down to the partners in the parking lot, with the receiver one meter off the ground.
| Bluetooth LE | |
| TX Antenna Height (m) | 6 |
| TX Power (dBm) | 4 |
| TX Antenna Gain (dB) | 0 |
| Frequency (MHz) | 2400 |
| RX Antenna Height (m) | 1 |
| RX Antenna Gain (dB) | -6 |
| Structure Loss (dB) | 11 |
| Sensitivity (dBm) | -93 |
| Margin (dB) | 20 |
| Range | 77 |
(Note: 11dB structure loss consistent with propagation through an 8" masonry block wall)
With one antenna on the second floor, the expected Bluetooth Low Energy range is 77 meters. That’s not enough to cover the entire lot. They search for other options beyond Bluetooth 4.0:
Want to learn about what we’re building at Link Labs? Click below to learn about the system with 2594 meters of range (using the same assumptions).