Construct a 6-15V Alarm

This project provides the schematic and the parts list needed to construct a very simple Alarm. This is a simple project and will help the beginners to electronics to understand one of the functions of 555 timers and one of their application. 556 timers has 2 of 555 timers.

General Description

The LM556 Dual timing circuit is a highly stable controller capable of producing accurate time delays or oscillation. The 556 is a dual 555. Timing is provided by an external resistor and capacitor for each timing function. The two timers operate independently of each other sharing only VCC and ground. The circuits may be triggered and reset on falling waveforms. The output structures may sink or source 200mA.

Features

a) Direct replacement for SE556/NE556
b) Timing from microseconds through hours
c) Operates in both astable and monostable modes
d) Replaces two 555 timers
e) Adjustable duty cycle
f) Output can source or sink 200mA
g) Output and supply TTL compatible
h) Temperature stability better than 0.005% per °C
i) Normally on and normally off output

Applications

a) Precision timing
b) Pulse generation
c) Sequential timing
d) Time delay generation
e) Pulse width modulation
f) Pulse position modulation
g) Linear ramp generator

The Connection diagram of a typical LM556 Dual timer is as shown below.

You will learn what 110dB of alarm sounds like. The piezo elements is set to oscillate around their resonant frequency. The sound generated is very loud and it can hurt your ears, so do be careful.

You can find the CK216 6-15V Alarm Module kit here under the SURVEILLANCE AND SECURITY (SPY) category.

ref: electronics-project-design.com/Alarm.html