Bluetooth / BLE Technology Solutions

What is Bluetooth Low Energy?

Bluetooth Low Energy (BLE, also Bluetooth LE) is a low-power variant of Bluetooth, introduced with Bluetooth 4.0 and maintained by the Bluetooth SIG. BLE operates in the licence-free 2.4 GHz band and is designed to transmit small amounts of data with minimal energy. As a result, BLE devices often run for several years on a coin cell. Because almost every smartphone, tablet and many gateways support BLE, the technology is extremely widespread and inexpensive.

How BLE is used in the IIoT

In industrial settings, BLE serves two main purposes. First, location: small beacons on tools, containers, equipment or on employees' clothing regularly broadcast their ID, and fixed receivers or smartphones detect which object is in which room or zone. Second, sensing: wireless sensors for temperature, humidity, vibration or door contacts report their values via BLE to a gateway. Many industrial devices also use BLE to be configured and read out via an app.

How a BLE location system is structured

A BLE location system consists of tags or beacons on the objects, receivers (locators or gateways) on ceilings and walls, and software that calculates position from the signals. The simplest method evaluates signal strength and achieves room- or zone-level accuracy, typically within a few metres. Direction finding from Bluetooth 5.1 onwards (angle of arrival) enables much more accurate positions, at higher cost for the receivers. Standards such as iBeacon and Eddystone define how beacons broadcast their ID.

BLE or UWB?

BLE is cheaper, more power-efficient and available everywhere, but with simple signal strength measurement it only achieves an accuracy of a few metres. That is enough to know which hall, gate or storage area something is in. UWB locates to within 10 to 30 centimetres and is suitable when you need to know the exact workstation or shelf position. Many companies start with BLE and add UWB where accuracy is not sufficient. omlox combines both in one system.

What to consider when choosing

First, the required accuracy matters: zone, room or metre. Next come battery life and transmission interval of the tags, because more frequent signals mean better timeliness but shorter battery life. Metal shelving, machines and people attenuate and reflect the signal, so receiver density should be tested on site. Finally, decide whether smartphones should also act as receivers or whether fixed gateways reliably deliver the data to IT.