Homemade bonsai atomizer

Single chip microcomputer STM32L151CCU6

1206RGB (single)

RF cable can be customized for other specifications

The device introduced in this article can create a layer of fog around the rockery and trees of the bonsai, just like the white clouds floating in the mountains, which greatly enhances the ornamental value.
First, the working principle circuit is shown in the drawing. Mainly by ultrasonic generator and water level controller (water level controller refers to the control of high and low water level by mechanical or electronic method, can control solenoid valve, water pump, etc., become water level automatic controller or water level alarm, thus coming Semi-automatic or fully automated.), power circuit and other components. The ultrasonic generator is mainly composed of a triode VT1, the VT1 and its peripheral components constitute a three-point LC oscillator, B is an ultrasonic transducer, and its natural frequency fc=1.65MHz. The capacitances C1 and C2 determine the oscillation amplitude, and its natural frequency is slightly lower than Fc, L1, C2 are positive feedback components, the natural frequency is slightly higher than fc, and VD5 is a protection diode of VT1. Since B is immersed in water during atomization, the water level controller is composed of VT2, VT3 and other components, and the role is:
(1) providing a base bias current for the oscillating circuit;
(2) When the water level in the bonsai is lower than the set value, the oscillator (the oscillator is an electronic component used to generate a repeated electronic signal (usually a sine wave or a square wave). The circuit formed by the oscillator is called an oscillation circuit. DC power is converted into an electronic circuit or device with a certain frequency of AC signal output. There are many types, which can be divided into self-excited oscillator and other oscillator according to the oscillation excitation mode; according to the circuit structure, it can be divided into a RC oscillator and an inductor-capacitor oscillation. , crystal oscillator, tuning fork oscillator, etc.; according to the output waveform can be divided into sine wave, square wave, sawtooth wave and other oscillators. Widely used in electronics industry, medical, scientific research, etc.) Stop vibration, play a protective role. VT2 and VT3 are connected into a composite pipe, and the base bias current is supplied to VT1 through L3 and R3, and L3 is a high-frequency choke coil, which prevents the ultrasonic signal from entering the water level control circuit. Adjusting the resistance of R1 can change the base current of VT1 to control the operating current of the whole machine. a, b is the water level control line, usually immersed in water. When the atomizer is working normally, if the water level drops to a certain limit, a and b will be off the water surface, VT2 and VT3 will be cut off, and the water level controller will stop providing the base current to VT1, and the whole machine will stop working.
Second, the component selection
The quality of VT1 is the key to successful production. It is best to use high-power high-frequency triodes such as BU406, BU407 or BU408 from Italy SGS, which requires fT≥100MHz; VT2 and VT3 can use NPN-type silicon tubes such as 9014, requiring β≥100; VD1 ~VD4 can use 1N4002 silicon rectifier diode.
All resistors are preferably RJ-0.25W metal film resistors; CBB-100V polystyrene capacitors are used for capacitors; inductor L1 can be wound around 27 mm on φ10×10mm core with φ0.51mm enameled wire, inductance is about 24μH; L2 is φ0. The 69mm enameled wire is wound around 2.5φ in φ6mm drill bit, and then taken off, the inductance is about 0.22μH; L3 can be 270μH color code inductor; transducer B is the key component, should use φ20×1.25mm/1.65MHz or φ20×1.2mm /1.7MHz high-intensity piezoelectric ceramic sheet; transformer T requires secondary voltage of 50V, power 40W; S uses small boat-shaped switch; VT1 is best to install radiator; transducer B can not be energized from water, otherwise it will burn out. The water depth in the bonsai is 4-6 cm, which should be clean. After mounting, adjust the resistor R1 so that the total current is about 0.6A.
All components can be mounted on the self-made printed board. The hollow rivets can be drilled and spliced ​​with thin plastic wood boards. The components can be connected and then connected with wires. The position of each component can be properly configured.