Here is simple electronic fun project which is designed using digital gate IC (CD4092BE) called nocturnal screamer. In absence of light it produce loud scramming sound but when light is switched on, sound will disappeared. In this way we can used this project for fun.
Circuit Description of Nocturnal Screamer
The circuit of nocturnal screamer is designed using quad two input NAND gate IC (CD4099BE). Here LDR is used as sensor which detects light and change its internal resistance corresponding to the light obtained on it. One NAND gat (N1) is used to sense the level of light, where NAND gates N2 and N3 are used to generate audio frequency. The audio output is given to the base of darlington pair made from transistor T1 and T2 for amplification. The amplified output from is fed to loudspeaker.
The sensitivity of LDR is adjusted by variable resistor VR1. This circuit produces sound only when LDR is kept in dark.
PARTS LIST OF NOCTURNAL SCREAMER
|Resistor (all ¼-watt, ± 5% Carbon)|
|R1 = 1 KΩ|
R2 = 10 KΩ
R3 = 33 KΩ
VR1 = 100 KΩ
VR2 = 47 KΩ
VR3 = 100 KΩ
|C1 = 10 µF/16V|
|IC1 = CD4093BE|
T1 = BC147
T2 = BDY60
D1, D2 = 1N4148
LS1 = 8Ω/0.5W