A do-it-yourself device using a single transistor can be made by almost anyone who wants it and makes a little effort to purchase very inexpensive and not numerous components and solder them into a circuit. It is used to automatically replenish water in supply containers at home, in the country and wherever water is present, without restrictions. And there are a lot of such places. First, let's look at the diagram of this device. It just couldn't be simpler.
Control the water level automatically using a simple electronic water level control circuit.
The entire water level control circuit consists of several simple parts, and if assembled without errors from good parts, it does not need adjustment and will immediately work as planned. A similar scheme has been working for me without failures for almost three years, and I am very pleased with it.
Automatic water level control circuit
Parts List:
- You can use any of these transistors: KT815A or B. TIP29A. TIP61A. BD139. BD167. BD815.
- GK1 – lower level reed switch.
- GK2 – upper level reed switch.
- GK3 – emergency level reed switch.
- D1 – any red Light-emitting diode.
- R1 – resistor 3Kom 0.25 watts.
- R2 – resistor 300 Ohm 0.125 watt.
- K1 – any 12 volt relay with two pairs of normally open contacts.
- K2 – any 12 volt relay with one pair of normally open contacts.
- I used float reed contacts as signal sources for replenishing water in the container. The diagram is designated as GK1, GK2 and GK3. Made in China, but of very decent quality. I can't say a single bad word. In the container where they stand, I treat the water with ozone and over the years of work there has not been the slightest damage to them. Ozone is an extremely aggressive chemical element and it dissolves many plastics completely without any residue.
Now let's look at the operation of the circuit in automatic mode.
When power is supplied to the circuit, the lower level float GK1 is activated and power is supplied to the base of the transistor through its contact and resistors R1 and R2. The transistor opens and thereby supplies power to the relay coil K1. The relay turns on and with its contact K1.1 blocks GK1 (lower level), and with contact K1.2 it supplies power to the coil of relay K2, which is an actuator and turns on the actuator with its contact K2.1. The actuator can be a water pump or an electric valve that supplies water to the container.
The water is replenished and when it exceeds the lower level, GK1 turns off, thereby preparing the next cycle of work. Having reached the upper level, the water will raise the float and turn on GK2 (upper level), thereby closing the chain through R1, K1.1, GK2. The power to the base of the transistor will be interrupted, and it will close, turning off relay K1, which with its contacts will open K1.1 and turn off relay K2.The relay, in turn, turns off the actuator. The circuit is prepared for a new cycle of work. GK3 is an emergency level float and serves as insurance if the upper level float suddenly does not work. Diode D1 is an indicator that the device is operating in water filling mode.
Now let's start making this very useful device.
We place the parts on the board.
We place all the parts on a breadboard so as not to make a printed one. When placing parts, you need to take into account to solder as few jumpers as possible. It is necessary to make maximum use of the conductors of the elements themselves for installation.
Final look.
The water level control circuit is sealed.
The circuit is ready for testing.
We connect it to the battery and simulate the operation of the floats.
Everything is working fine. Watch a video about tests of this system.
