Measurement of pond temperature and pH using an aqueous sensor network

We report on the development and application of an aqueous sensor network (ASN). Designed for operation in lakes or drinking water reservoirs, the immersed ASN nodes are secured in place at a controlled depth by use of anchors with a node to node separation distance of less than or equal to 20 m. The individual nodes are integrated with various types of sensors enabling measurement of both physical and chemical analyte parameters. Node operation is overseen by programmable microcontrollers; the software on the microcontrollers is structured in a modular format so it can adapt to different types of sensors without extensive reprogramming. Node-to-node communication is achieved using timed bursts to avoid interference from unwanted signal reflections arising from the impedance mismatch at the water-air and water-land interface. We report on the application of the ASN for monitoring temperature and pH throughout a small pool. As desired the individual nodes of the ASN can be integrated with suitable chemical/biological sensors to detect down stream effluents from a source, or to ensure water reservoir quality.