About Wireless Sensor
(Underground Wireless Communication System)

This is a wireless data transmission system through the underground, rock and water using low frequency electromagnetic wave.

Wireless sensor measures at the set time and logs data.
When the Receiving unit transmit the command to the wireless sensor, wireless sensor responds to the command and transmits the data.


For example when we measure a water pressure in rock, we have to chain the data logger to the sensor by cable at any measurement point. But, such cables are in danger of breaking, insulation failure or making weak points in structures. To resolve these problems, we developed "Wireless Sensor: Underground Wireless Communication System". Wireless sensor transmits data through the underground, rock and water with low frequency electromagnetic waves. For example in underground, transmission distance could be more than 100m. This system are consists of a receiving unit based on land and wireless sensors. The receiving unit are made up of a transmission antenna, a receiving antenna, a control unit and a mobile PC. The wireless sensor incorporates a data logger, a antenna, a battery and sensors. When the Receiving unit transmits the command to the wireless sensor, wireless sensor transmits the data corresponds to the command.


Classification of radiation frequency

Very Low Frequency Electromagnetic Wave

Normally, a radio communication system through the air uses the radio waves between a few hundred kHz to GHz.
The Wireless Sensor uses very low frequency electromagnetic waves of a few kHz. Low frequency electromagnetic waves behave like static electromagnetic field. So this system can transmit through the underground.


Merits of wireless

Perfect cut-off of water
No weak point
No influence of lightning
Avoid to missing data due to a cable damage
Low placement cost
No cable cost



Dam monitoring system
Settlement measurement
Infrastructure monitoring
Waste disporsal site
Location finding



Copyright (c) 2004 Sakatadenki Co.,ltd. All rights reserved.