COMFORT FOR THE FISHThis scheme will be useful for those who grow in the aquarium ornamental fish. As you know, aquarium Pets should be illuminated most of the day. Industry produces automatic timers, lighting for aquariums and air compressors (pumps) that operate according to a given algorithm. The proposed device, checked by the author, is able to replace industrial automation.


An advantage of the proposed device are the low cost of parts and the simplicity of the design that can collect almost any student familiar with the basics of electrical engineering and able to work with a soldering iron. This system is useful for landlords and several large aquariums that are installed in the hallways of companies and organizations, and is also in need of an automatic (or semiautomatic) service.
A circuit diagram of a device for automatic control of lighting and compressor consists of two timers (timer relay). When power is applied relay K1 (on the trigger voltage of 9-12 V) starts immediately its contacts K1.1 include a relay K2, and KZ, and KZ through the contacts.2 power is supplied to the first timer—IC K561LA7. The contacts K3.1 open and allowed to charge the oxide to the capacitor C2 of the timer. When the latter is charged to the level of the switch logic gate circuits, the output of the element DD2.1 will be a logic level “1”, and accordingly, the output of the element DD2.2 is a logic level “0”. This signal is sent to the control input of the second timer DA1, which will turn off relay K1 and start to count a new time delay set by the values of the elements R2, C1. Under these schemes the values of the RC-chain, R2, C1 and R3, C2 (the sliders of variable resistors in the middle positions) of the first aging timer at the logical elements K561LA7—burning time of the lighting of the lamp HL1 installed for the aquarium, will be 2 hours and 15 minutes and the exposure time of the second timer on the chip КР1006ВИ1 (the time when the lamp is extinguished)-1 hour. The job of the timers is done in a round-Robin algorithm.
The time delay can be adjusted within wide limits by changing the values of these RC-combinations. This device can also be used for other purposes (periodic heating of the aquarium, the compressor for feeding the fish, the air, etc.).
With proper items and proper installation of the device does not require adjustment. Chip DA1 is constantly under tension. On pin 14 of the chip DD2, the power is constant (+Un) and common wire (building) served on 7-th output DD2 through the switching contacts of the relay K3.2.
Parameters power supply: input chip stabilizer КР142ЕН8Б (pin 3) should follow the rectified supply voltage +15…+17 V. Relay K2 should be used for the corresponding supply voltage (passport RS4.591.003). Relays used in this unit, you can replace foreign analogues, suitable electric characteristics, for example, Relpol RM85-2011 -35-1012.
The power transformer T1 is any suitable network, with an output voltage at the secondary winding 13-16 In, for example, TCE-110L, CCI-277-127-2250/50 or similar. In operation of the device should comply with electrical safety measures, since the transformer T1 and an electric circuit (switched by the relay contacts) under the voltage of 220 V.
A. KOSHKAROV, Saint-Petersburg

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