One Sensor, Ten Streetlights: Solar-Powered Mesh Network Spots Faulty Lamps and Dangerous Leakage Currents in Real Time

Streetlights fail quietly. A blown bulb on a dark stretch of road may go unreported for weeks, and a leaking current inside a corroded lamp post can pose an electrocution hazard long before anyone notices. A new study published in Frontiers in Sensors proposes a centralized mapping architecture that could change how cities detect these failures, using a wireless sensor mesh network in which a single solar-powered node monitors the electrical behavior of ten streetlights at once. According to the authors, Swarnajit Bhattacharya of National Yang Ming Chiao Tung University in Taiwan and Biswajit Mandal and Banshidhari Samanta of Haldia Institute of Technology in India, the approach cuts sensing hardware requirements by roughly 90 percent compared with conventional one-sensor-per-pole designs while achieving fault detection accuracy above 97 percent.

The core insight of the architecture is that streetlight clusters behave like a collective electrical fingerprint. Instead of attaching dedicated sensing and communication hardware to every lamp post, the system groups ten streetlights under the supervision of one ESP32 microcontroller node. That node continuously samples voltage, incoming and outgoing current, and other electrical parameters, then transmits aggregated diagnostic data over a multi-hop wireless mesh to a centralized monitoring station. Because the sensing burden is shared across a cluster, the number of deployed devices—and the cost, installation labor, and embodied carbon that come with them—drops dramatically.

What distinguishes the system from earlier smart streetlight schemes is the breadth of faults it can catch. Most existing monitoring platforms focus narrowly on whether a lamp is on or off. The proposed architecture goes further, identifying faulty bulbs through near-zero current draw at nominal supply voltage, detecting leakage currents as a steady differential current exceeding safe limits, and flagging ground faults through a severe transient current spike paired with an instantaneous voltage drop. These last two categories matter for public safety: leakage currents and electrocution hazards at lamp posts are rarely addressed by commercial systems, yet they represent a genuine risk to pedestrians and maintenance crews.

The detection engine is built on statistics rather than fixed thresholds. During commissioning, the network establishes a baseline from ten fully operational streetlights, recording seven-dimensional feature vectors that include RMS voltage and current, total harmonic distortion up to the tenth harmonic, power factor, and RMS residual current. Each feature is computed over observation windows of 500 samples taken at 5 kilohertz, spanning five mains cycles, which suppresses single-sample analog-to-digital converter noise and transient switching spikes. From this baseline, the central station computes a mean vector and a covariance matrix, and each node then evaluates the Mahalanobis distance—a statistical measure that accounts for how the electrical parameters vary together—between live readings and the healthy reference.

When that distance exceeds a calibrated threshold, a fault flag is raised. The threshold is not chosen by trial and error: under a multivariate Gaussian assumption, the squared Mahalanobis distance follows a chi-squared distribution, so the team derives the cutoff analytically to hit a target false-alarm rate. For seven features and a 1 percent false-alarm target, the threshold works out to 4.93. The covariance matrix is regularized using the Ledoit–Wolf shrinkage method to guarantee it remains invertible even when features such as voltage and current become highly correlated under stable grid conditions. Crucially, the heavy matrix inversion is done once, offline, at the central station; each ESP32 receives a precomputed 196-byte inverse matrix, so the online computation reduces to a single matrix-vector product that executes in well under a millisecond on the microcontroller’s 240 MHz dual-core processor.

Communication reliability is handled by a self-healing mesh protocol. Every node acts as both a sensor and a relay, aggregating its own diagnostic payloads with data from downstream neighbors before forwarding them toward the sink. Routing paths are chosen by a dynamic cost function that weighs link quality and each neighbor’s residual energy, so traffic flows over the strongest, most sustainable routes. If an intermediate node fails, a beaconing mechanism detects the loss within 15 seconds—three missed hello beacons at 5-second intervals—and the affected node prunes the dead relay from its routing table and recalculates an alternate path. The authors’ probabilistic analysis shows that as node density increases, the probability of successful data delivery approaches one, meaning the network becomes more resilient, not less, as it grows.

Energy efficiency is engineered into every layer. Nodes spend most of their lives in deep-sleep mode, waking to sample electrical states on a low-duty-cycle TDMA schedule and transmitting only on fault detection or scheduled heartbeats. The average node power, including the radio, comes to 184.6 milliwatts, and a backup battery sustains operation for 7.5 days under typical urban channel conditions. Solar panels recharge the nodes, eliminating the need for additional grid power infrastructure and shrinking the carbon footprint of the monitoring network itself. The mesh topology also extends coverage across large urban areas, since nodes relay information through neighbors rather than requiring direct lines to a central station.

In simulation studies emulating a real-world urban deployment, the architecture delivered fault detection accuracy exceeding 97 percent with a low false-alarm rate, and the mesh network achieved packet delivery ratios close to 99 percent with low latency. The self-healing routing mechanism rerouted diagnostic data around failed intermediate nodes without interrupting transmission, and reliability analysis confirmed that overall network availability climbs with node density. A correlation analysis further revealed that voltage and current stability strongly predict fault detection accuracy, while mesh connectivity significantly influences packet delivery and fault localization performance—evidence that the electrical and communication layers reinforce one another.

The system’s most visible feature for city operators is its geographic intelligence. A centralized GIS-based mapping interface visualizes faults in real time, pinpointing the location of a defective streetlight cluster so maintenance crews can be dispatched directly to the problem. The authors argue this capability should shorten maintenance response times and improve operational efficiency compared with the prevailing model of manual inspection rounds and reactive public reporting, which delays fault detection and inflates operational costs. A comparison table in the paper shows that prior systems—from early 2007 wireless sensor network prototypes through ZigBee-based controllers and IoT platforms—generally lack leakage current detection, GIS mapping, mesh networking, solar power, and multi-light monitoring in combination, whereas the proposed architecture integrates all of them.

The work remains at the simulation and prototype stage; the hardware validation described includes an ESP32-based sensor node with a switching relay module and LED array simulating streetlight loads, alongside an Arduino gateway with a Bolt IoT wireless module for data logging. The authors outline future directions including full-scale field deployment, machine learning for predictive maintenance and fault forecasting, and integration with digital twin platforms and edge computing. If those steps succeed, the cluster-based monitoring strategy could offer municipalities a practical template for scaling intelligent infrastructure: fewer sensors, longer battery life, self-healing communications, and a map that shows exactly where the next dark street—or hidden electrical hazard—awaits repair.

Subject of Research: A centralized wireless sensor mesh architecture for automated streetlight fault detection and GIS-based fault localization

Article Title: A centralized mapping architecture for Automated Streetlight Fault Detection via Wireless Sensor Mesh Networks

Article References: Bhattacharya, S., Mandal, B., & Samanta, B. (2026). A centralized mapping architecture for Automated Streetlight Fault Detection via Wireless Sensor Mesh Networks. Frontiers in Sensors, 7, Article 1905827. https://doi.org/10.3389/fsens.2026.1905827

Image Credits: AI Generated

DOI: 10.3389/fsens.2026.1905827

Keywords: streetlight fault detection, wireless sensor networks, mesh networking, smart cities, ESP32, Mahalanobis distance, leakage current, GIS mapping, solar power, Internet of Things, fault localization, energy efficiency