Bird Bath Fountain Monitor circuits

A bird bath fountain (a small shallow pond-created with a water-filled basin- in which birds may bath and from which they may drink) can be a garden ornament, small reflecting pool, outdoor sculpture, and part of creating a vital wildlife garden. It is an attraction for many different species of birds to visit gardens, especially during the summer and drought periods. This fountains that provide a reliable source of water year round add to the popularity and micro-habitat support. Presented here ia an “add-on” electronics circuit for bird water baths.

The circuit constantly monitor the water level in the bath, and brings up an audio&visual warning signal when its sensor probe notices that the water level is very low, or the bath is in dry state. It can be powered from any 9VDC adaptor or similar power source.
After construction, fit out the sensor probe inside the bird bath in an appropriate position and connect it to the remotely-located (usually inside the house) master circuit using high-quality twisted-pair/flat cable. The sensor probe can be constructed from a pair of new injection needles. The needles should be firmly fixed about 10 mm apart on a piece of laminated plastic sheet.

Working of this circuit is very simple! Here, a “gimmick” potential divider ( P1, R5 and the sensor probe J1) is wired at the base of transistor T1 (BC547) to switch it on when water is available between the needles of the sensor probe (J1). Conduction of T1 pulls down the reset terminal (pin 4) of the astable oscillator IC1 (LM555) and hence the astable is disabled in standby state. Potentiometer P1 (1M) sets the threshold level.
But when the sensor probe is dry, IC1 is enabled by R1 (4K7) and the piezo-buzzer (BZ1) starts beeping at near 3Hz rate. Red LED serves as a flaunting visual indicator. Electronics Circuit Application