This is the electronic circuit diagram of aquarium temperature probe capable to monitor the temperature of water and indicate the rise in temperature through buzzer indicators. This circuit uses diode 1N34 as the temperature sensing probe. The resistance of the diode will vary depends on the temperature in its vicinity.
IC1 = CA3140, IC2 = LM3915, IC3 = 7805
R1-R2 = 47K, R3 = 470ohm, R4 = 100K, R5-R7 = 1K
VR1 = 1K, VR2 = 1M, VR3 = 50K, VR4 = 1K
C1 = 1uf 25v
T1 = BC557
D1 = 1N34
LEDs (Red & Green)
PZ1 = Piezo Buzzer
Note- For LEDs protection used 330 ohm’s resistor in series with LEDs.
The environmental factors including light and temperature affect fish culture. The temperature of water has profound effect because fish cannot breed above or below the critical temperature limits. Temperature between 24oC and 33oC is found to be the best to induce spawning in fishes. This particular temperature range is also necessary for the healthy growth of fishes. Rise of water temperature due to sunlight may adversely affect the fish rearing process.