Border surveillance with edge AI and no network required
How Venturus created 'Silent Guardian', an ultra-low-power device that detects the sound of motors in remote border areas where no infrastructure is available.
Case context
In remote forest regions, border zones, and support areas used by Special Border Platoons, monitoring territory runs into a basic limitation: there is no network coverage. Vegetation is dense, humidity is extreme, and getting teams on-site is both difficult and expensive.
The challenge came from a real need raised by the Brazilian Army: how can authorities tell whether illegal activity is happening in these areas, such as river piracy or illegal mining? Put simply, how can they know if someone has been there—or is there right now?
Just as important, alerts need to be reliable enough to justify sending response teams into the field. The real value lies in a system that can distinguish occasional background noise from consistent signs of human activity.
Conventional cameras and sensors require internet access, power infrastructure, and frequent maintenance. In these regions, none of that exists. A different approach was needed.
What the device needed to do
To operate deep in the forest, the sensor had to meet three requirements at the same time:
Work offline
Operate without cloud connectivity or external communications infrastructure
Use extremely low power
Support long deployments in the field without constant battery replacement
Separate signal from noise
Deliver reliable alerts in an acoustically saturated forest environment
The solution: 'Silent Guardian'
Venturus developed Silent Guardian, an end-to-end acoustic detection system that identifies the sound signature of motorized equipment - such as small riverboats, chainsaws, and excavators - amid the constant noise of the forest.
The principle is simple:
Forest sounds are irregular, with energy spread across the spectrum. Motors, by contrast, produce stable, repeating frequencies over time. That consistency makes it possible to detect human activity - even when the engine is not the loudest sound in the environment.
Listen to the difference:
How the device works
Edge AI
AI processing runs entirely on the device itself. With no need for internet access, the sensor operates fully autonomously.
Adaptive filtering
The system continuously adjusts to rain, wind, and other changing forest conditions in real time.
Ultra-low-power hardware
The algorithm and processor were designed together so the sensor can listen continuously while consuming as little energy as possible.
How alerts reach authorities
The sensor itself does not have internet access, but alerts can still reach the command base through three different paths, used independently or in combination depending on field conditions.
Sensor-to-sensor relay
Each sensor passes the signal to the next
Hub with satellite uplink
Multiple sensors, a single satellite transmission
Patrol pickup
The patrol collects the signal and takes it back to base
Results
'Silent Guardian' was presented to the Brazilian Army in a functional proof of concept, with tests alternating between forest recordings and recordings of a motorboat moving through the forest environment. The project is still in development, and the results below refer to that demonstration - not to a live field deployment.
High accuracy in detecting engine sound patterns
No false alarms triggered by transient forest noise
Processamento e análise de IA 100% no dispositivo