Here is a fun project to set up a model battlefield using some components. The project mini laser turret can amidst the miniature battlefield.
Circuit Description of Mini Laser Turret:
The circuit of mini laser turret is designed around dual timer IC (NE556) and two servo motors. IC NE556 is a combination two timer IC (NE555), which is used to generate the pulse for drive servomotor. Each timer IC is used in astable mode whose frequency or period is depends upon RC components connected to it. It’s high period can be calculated by using formula:
0.69 * (R1 + R2) *C1 where, its low period is calculated by formula:
0.69 * R2 *C
From above formula we can say that low period only depends on the value of resistor R2. In this circuit we use combination of resistor R1 and R2 as an equivalent of R2, which change the overall frequency.
The lower period can be varies easily by varying the value of R2, but the servo motor controlled by high period only. The output of timer IC is connected to base of transistor through resistor. Here, transistor is used in inverting mode i.e. it invert the output of timer IC, converting the high into low and vice-versa.
Parts list of mini laser turret
|Resistor (all ¼-watt, ± 5% Carbon)|
|R1, R3, R5, R7 = 1 KΩ, 0.5W
R2, R4, R6, R8 = 10 KΩ, 0.5W
R9 = 100 Ω
VR1, VR2 = 1 KΩ linear potentiometer
|C1, C3 = 1 µF/16V electrolytic capacitor
C2, C4 = 10nF Ceramic Capacitor
|IC1 = NE556 dual timer IC
T1, T2 = BC548
D1 = 3mW Laser Diode
|M1, M2 = 9g servo motor 4.5 – 6V
SW1 = Toggle Switch
B1 = 6Volt Battery