Apparatus suitable for repelling insects and rodents. As compared to similar devices, commercially available, this device is characterized by the possibility of a smooth change in the operating frequency and the intermittent operation of (break time / work can be adjusted). With this repellent is much more efficient in operation.
- acoustic – piezoelectric transducer
- LED operation indicator
- smooth frequency control
- modulating control signal and the pause duration
- power supply 3…15 In DC. (Recommended power supply – 1 type of battery “Crown” 9AT
- size sample board: 50 × 49 mm.
The main components of the scheme are three popular CMOS integrated circuits and piezoelectric transducer in an electro-acoustic transducer. scheme, regulating the duration and the disconnection signal deterrence, It provides a simple oscillator, built on one of the six inverters Schmitt chip U1.
Potentiometer P1 sets the total time – the duration of the cycle "operation + break", P2 and sets its proportions. For given values of the elements or the maximum duration of the interruption operation is 36 with, minimum 0,5 with. Another four inverter U1 connected in parallel to each other, and their inputs are connected directly to the output of generator inverter U1A. Parallel connection of inverters allowed, if they are located in a single integrated circuit. Inverters increase current efficiency U1A. U1F controls steering diode D4. Integrated circuit U1 cyclically enables and disables remaining elements U2 and U3. U2Ai U2B – a generator of high-frequency acoustic signals. Adjustment is made by means of a potentiometer P3. U2C acts as a buffer, while U2D inverts the phase of the signal, appears at the output U2C. This phase inversion is required, U3 because it acts as a bridge amplifier signal, generiruemogo U2. This slightly increases the efficiency of the amplifier (range) and necessary, especially under reduced power.
Installation and setup
Arrangement of elements on the sample circuit board shown in Figure 2.
After soldering all the elements connect the power supply and adjust the potentiometers required working time, cliffs and the frequency of the generated sound. Time and frequency set experimentally, from time to time watching the work efficiency. While insects (For example, mosquitoes, flies), These frequencies should be in the range of 18-50 kHz, and in the case of rodents – about 10-20 kHz. can not be guaranteed 100% effectiveness of the apparatus described, but the possibility of fine adjustment, undoubtedly, allowing it to radically increase. However, this requires experimentation, ie monitoring the effects device.