Bluetooth Low power for safer maintenance of smart street lights

Replacing traditional street lights with interconnected street lights based on energy-efficient leds is an effective way to reduce energy consumption and associated emissions. For example, the city of Bradford in the United Kingdom uses a remote wireless network to control LED smart street lights, and the local municipality estimates that these devices can reduce electricity consumption by 65% and associated carbon emissions by more than 6,000 tons per year compared to traditional lighting. Since traditional street lights account for 30% to 50% of the city's total electricity consumption, this savings is of great significance for achieving the goal of "zero carbon".

In addition, according to the Bradford City report, smart street lights require less maintenance than traditional street lights, and the service life is six times that of old low-pressure sodium lamps. However, although maintenance needs are reduced, smart street lights still need to be repaired. Short-range radio technologies such as Bluetooth Low Energy have found a place in this regard, making it safer and more convenient for technicians responsible for maintaining smart street lights.

Drive LED lighting

LED lighting is more complex than the traditional lighting it replaces, such as low-pressure sodium lamps. LED lights need to use a carefully controlled constant current and constant voltage power supply to avoid overheating and premature failure. This is done by a precision power device called a driver. The driver converts the input 240 V AC mains voltage into a tightly controlled low DC voltage to meet the stringent requirements of leds.

Today's advanced drives go beyond voltage conversion and are equipped with operating software and industry-standard technologies such as the DALI2 protocol that enables two-way digital communication between lighting control devices. This communication supports fine control between the driver and the LED, allowing for features such as phased dimming, which reduces lighting when there are few pedestrians on the street, thus saving more energy. Other features include gradually increasing the operating voltage as the LED ages to maintain a given brightness.

Wireless technology improves convenience and security

Bluetooth Low Energy is interoperable with smartphones and can be used to debug and configure new LED drivers, followed by over-the-air (OTA) diagnostics and firmware updates. During maintenance, lighting technicians store software bug fixes on the phone and transmit them to the drive via a low-power wireless connection, which then verifies the update and confirms it back to the phone via a two-way link.

In addition, driver technology has improved over time, and engineers have learned more about the long-term performance of LED lights, and as LED lights become more efficient, the operating parameters of solid-state lighting change, and wireless connectivity enables complete software updates to match. You can save time and money by updating the software to upgrade the performance of the installed drives while keeping the original hardware.

Another significant advantage of wireless connectivity in terms of driver maintenance is security. With OTA firmware updates, technicians can repair or upgrade drives over the network without having to physically turn on smart street lights, avoiding the risk of being harmed by dangerous voltages.
The LED driver uses Nordic Bluetooth low energy products.

LACROIX Environment, a manufacturer of Nordic Semiconductor customer telemetry and SCADA solutions, has released an LED driver with low-power Bluetooth wireless connectivity called the PS-Pak. Insight SiP ISP1507-AX module based on Nordic nRF52832 SoC was used.
The SoC features Bluetooth low-power wireless connectivity and can be configured with the PS-Pak via the relevant iOS or Android app on a smartphone, so there is no need to physically turn on the inside of the high-voltage lighting unit. Over-the-air software updates are also possible over a wireless connection. A PS-Pak can be configured for up to six LED drivers on the same pole.

Smart street lights become mainstream

Smart street lights with LED lighting have become mainstream. According to Research and Markets analysis, 23 million independently controlled smart street lights have been installed worldwide by the end of 2022. As traditional low-pressure sodium lamps become obsolete and countries pursue zero-carbon goals, this number will reach 63.8 million by 2027.

Long-distance wireless connections such as cellular iot or DECT NR+ enable citywide networking of smart street lights, but short-range wireless connections such as Bluetooth Low Energy also play a key role, enabling technicians to easily configure and update LED drivers while maintaining a safe distance from high-voltage power sources.