This is a tutorial on an Ultrasonic sound generator. Ultrasonic waves are those sound waves whose frequency is greater than 20KHz. It is not audible to human beings but can be heard by animals. Ultrasonic devices are usually used for repelling bugs or animals. There are lots of Ultrasonic devices available commercially. Pest repellants, rodent repellants, mosquito repellants, etc. are some of them.
This circuit is using a simple approach to make an adjustable sound generator using 555 IC. You all must be aware of the fact that the 555 IC is the most versatile and famous IC in the world of Electronics. This IC provides an oscillation frequency ranging from 670 to 680Hz. In this circuit, we are using this as an astable multivibrator. As an astable multivibrator, this IC will continuously switch between its two unstable states.
Hardware Components
| S.no | Components | value | Qty |
|---|---|---|---|
| 1. | IC | NE555 Timer | 1 |
| 2. | Variable Resistor | 120K | 1 |
| 3. | Speaker SP1 (Piezo or tweeter) | – | 1 |
| 4. | Resistor | 20K | 1 |
| 5. | Capacitor | 2nF | 1 |
| 6. | Battery | 9-12V | 1 |
Circuit Diagram
Working
The circuit above is very easy to build and has a few components. The operating voltage of this circuit is 9-12V DC. This circuit is configured on the astable mode of operation. A variable resistor of 100K is used to set the desired frequency. As the resistance will increase or decrease different frequencies will generate. You can adjust it according to your purpose.
A piezo or tweeter can be used as a speaker SP1 for this circuit. Output sound waves of this circuit are beyond the audible range you won’t be able to hear them.
Applications and Uses
- Ultrasonic proximity sensors
- Robotic projects
- Bugs/Animals Repellants
- Ultrasonic obstacle detectors
- Ultrasonic distance sensors
