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Proximity-Based Smart Locking with TI’s Bluetooth Low Energy Tech – Embedded World 2025
At Embedded World 2025, we were excited to have partnered with Texas Instruments on this article to discuss their Proximity-Based Smart Locking System powered by their latest Bluetooth Low Energy technology. The setup uses a technique called channel sounding, introduced in Bluetooth 5.4, which enables accurate distance measurement between devices by analysing the phase offset of exchanged signals.
In the demo, a mounted unit containing a CC2755 device communicates with a mobile phone acting as a reflector. As the phone moves closer or farther away, the door automatically locks or unlocks. A GUI displays real-time distance data along with an animation of the door’s state—demonstrating the system's responsiveness.
Improved Accuracy and Real-World Applications
Channel sounding delivers a significant improvement over traditional RSSI-based distance estimation. With sub-50 cm accuracy, it provides the precision needed for secure hands-free access control systems. In contrast to older methods, it avoids accidental triggers caused by signal noise or fluctuations.
Beyond smart home security, the technology also applies to asset tracking, inventory management, and indoor positioning. During the demo, the system maintained reliable operation over distances of 30 to 40 metres, with headroom to scale further depending on use case and environment.
On-Chip Processing with CC2755 APU
The CC2755 includes a dedicated Algorithm Processing Unit (APU), enabling local post-processing of ranging data. This reduces the need for an external host, improving efficiency and lowering overall power consumption. It also allows more complex algorithms to run on the device itself—streamlining the solution for compact, battery-powered designs.
The result is a single-chip solution capable of high-accuracy ranging without compromising on speed or energy usage. As described in the demo, the APU "lets you do it quick without draining your battery.”
TI’s Bluetooth Low Energy solution highlights how smart access systems can benefit from accurate, efficient proximity detection. With improved ranging precision, on-chip processing, and strong BLE integration, devices like the CC2755 are ideal for smart homes, industrial tracking, and beyond. Learn more at TI.
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Residing on the south coast of England, Rich has spent the last few years building Electomaker.io from the ground up. He is usually found behind a laptop coordinating the rest of the EM team and occasionally finding time to contribute articles to the blog. When not tapping away at a laptop, he can be found either paddleboarding, at the beach, playing golf (badly), or camping with his family.
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