The Receive Unit can be a hand-held battery powered unit with a liquid crystal display or a more sophisticated base unit normally housed in an office type environment, however this has been used successfully in a fisherman's shack.

The hand held unit displays only height and temperature information and is primarily aimed at the fishing fraternity – the electronic equivalent of a stick in the water!

The base unit, however, has a number of functions: Firstly it receives and validates a legitimate frame from the transmit unit. It then strips out the height, temperature, transmit battery state (and other parameters not yet defined for e.g. meteorological data) and verifies it. The data is then statistically analysed to ensure that anomalies are averaged out (e.g a boat, canoe or bird passing underneath the transmit unit while sampling). A decision is made on a large number of samples on whether the water has risen by 60cms (approx 2 ft) or the water has risen to within 100cms (1 metre or 3ft 3”) of the transmit unit. The first gives rise to a river alert causing the dialler to ring up to four numbers and inform the recipient(s) that this is so. The second does the same except informs of a “main alarm”.The dialler dials seven times if not acknowledged.

Transmit unit

One of the advanced features in the Enhanced Receive Unit, allows interested parties to interrogate the unit and receive an SMS textt containing the height information. Also this unit will send and SMS text once certain conditions have been breeched e.g. such as the river rising by a foot and/or the height becoming dangerously high. This unit is supplied with a Pay-as-you-Go sim card with an initial credit to allow texting. It is up to the operator to make sure it is kept topped up once in the field.

 

Also available are units that connect to the Internet and display the height information on a web page. This may or may not include a “River Cam” to let users see the river state in real-time. This sort of installation is more applicable to rivers with large catchment areas and would require more detailed planning for application.

 

Note: multiple receivers can be used with 1 off Transmitter.

 

The Hand-Held Unit was primarily designed for the fisherman. It is pretty much agreed amongst the river fishing fraternity that the best way (at present) to judge whether a river is rising or falling is to place a stick in the water and mark the waters present position on it. The handheld unit is the electronic analogy of this, but does not require any intervention with the water. As the fisherman passes where the Transmit unit is situated the unit will receive a current value of the river height. This is then displayed together with a simple trend indication (up, down, same).

 

The hand-held device is also useful for checking that the transmit unit is in good health and also for a simple method of obtaining current height data.

 

Software (LevelReader V 0.9.0)

 

This is the display (left) of the Level Reader River Height Software.

 

It has the following facilities:

 

It runs on a conventional PC running Windows XP

Receives RS232 data from the Receive Base Unit

Stores the data on a "Session" file for retrieval later

Records data in real time

Stop and Start utility

Threshold detector and alarm

 

Specifications:

Sizes: Transmit and Receive units are approx. 150 x 150 x 100 mm. IP67 water immersion rating (Transmit Unit only) light grey thermoplastic.