## Electronics Grasshopper

Here is another fun project for children as well as electronics beginners. We often hear the sound of grasshopper or cockroach (i.e. shrill sound) at night. The project published in this website Electronics grasshopper produced PI-PI sound (sound like grasshopper) and can be used as doorbell.

### Circuit description

The entire circuit of electronics grasshopper is build around pair of timer IC (NE555) followed by few passive component (resistor and capacitor). Both the timer IC (IC1 and IC2) is used here as astable multivibrator. The frequency of IC1 is used to modulate the frequency of IC2 which further given to speaker from pin 3 of IC2 through capacitor C4. The modulation frequency of IC1 is obtained as saw tooth voltage at pin 6 given to control pin 5 of IC2 in order to control frequency of IC2. IC1 is low frequency oscillator where IC2 is high frequency oscillator. The saw tooth voltage at control pin 5 of IC2 make output audio frequency (3 – 30 KHz) high and low and listen as shrill sound of insect (pi-pi sound of grasshopper).

### PARTS LIST

#### Resistor (all ¼-watt, ± 5% Carbon)

R1 = 3.3 KΩ

R2, R4, R5 = 10 KΩ

R3 = 8.2 KΩ

#### Capacitors

C1 = 0.01 µF/50V

C2 = 4.7 µF/10V

C3 = 0.033 µF/50 µF

C4 = 220 µF/25V

IC1, IC2 = NE555

#### Miscellaneous

L.S. = 8 Ω speaker