Anti sleep Alarm for

Ηλεκτρονική - Συσκευές

2 Νοε 2013 (πριν από 4 χρόνια και 6 μήνες)

104 εμφανίσεις

Indian Institute of Technology

Anti sleep Alarm for
Students

M.
Rohit

Reddy
-

cs12b1022

Soumith
Raju

K

cs12b1037

T
Rohit

Reddy

ee12b1035

Circuit Diagram:

Uses:

This circuit saves both electricity and time for students.

It helps to prevent them from dozing off while studying.

It
is also useful for
drivers.

It can be used in heavy vehicles which travel during nights.

Components

IC1 (CD4093),IC2(CD4020)

Piezo

elec

buzzer

Relay switch

60watt 230v bulb

12v DC adapter and AC power supply

Resistors and variable resistors(22kohm), transistors,
diodes, capacitors

Push on button

Connecting wires

How does our circuit works
???

Every 30 min , the buzzer sounds just like snooze.

The buzzer sounds for 1 minute until the push on
button is not pressed.

If the push on button is pressed, the buzzer resets for
the next 30 minutes.

If the button is not pressed , the bulb goes off.

The circuit is built around
schimdt

trigger
NAND gate IC1, timer IC2, transistors BC547,
relay RL1 and buzzer.

IC1 is used to generate clock for the timer IC2.

The time period can be calculated as

T=1.38 x R x C, R= R1 + VR1, C=C2.

The timer IC 2 is 14 stage ripple counter.

Around half an hour after the reset, transistors T1,T2
and T3 drives the buzzer to sound and intermediate
beep
.

If IC2 is not reset at that time, around one minute
later, the output of gate N4 goes high and transistor
T4 conducts.

As the output of gate N4 is connected to the clock
input (pin10) of IC2 through diode D3, further
counting stops and relay energizes to deactivate all
the appliances. This state remains same until reset.

Time calculations:

R= R1 + VR1 = 15 kilo
-
ohms

C= C2= 10 micro
-

T= 1.38 RC = 0.21 seconds, as IC2 is a 14 stage ripple
counter, the time delay is calculated as follows:

t
1= 2**13 (2 to the power 13) * 0.21= 28.73 minutes.

And time delay to put off the bulb is

t
2= 2**8 (2 power 8) * 0.21 = 53.8 seconds

**Thank you**