Science Info

Home Alarm system

Simple, Secure, Fast and Cheap.

• only few components
• max security with Rolling Code TX and Shock Sensor with variable sensitivity
• the alarm module can be assembled in only 2 hours and it don't need manual preset
• with this characteristics is the most cheap system and the total cost could be reduced using a normal external sounder (escl. AG8)
• GSM module will be add in the future for a remote control

Introduction

This project born to protect my house.

Transmitters

All the functions of this Home Alarm system will be activated and deactivated by this little Rolling Code

transmitter show in the photo

The Rolling Code is the most secure method to transmit data and reduce risk of scan.

With this method the serial number of any transmitter is stored in the receiver at the learning time.

This serial number is composed by many bits so to find it with a scanner it is impossible because it need many time.

Four button for these functions:
A) manual start of sound and light alarm
B) enable protection of the system
C) make a phone call (future characteristic)
D) disable protection of the system

External Sounder & Strobe

The AG8 is a microprocessor controlled external sounder with a built in strobe. It was designed for simple installation, and offers a wide variety of features and safeguards. Features include silent installation, and two flash settings, optional sounder settings (multi-sweep or two tone), selectable timer, simple testing, and diagnostic LED's that can be viewed after the covers are fitted .

· High impact polycarbonate moulding.

· Horizontal or vertical mounting.

· One standard built-in wrap around strobe lens.

· Double skin construction.

· NiCad back-up battery included.

· Multi colour options.

· Front and rear tamper.

· Two Piezo sounders.

· Dual tones.

Internal Sounder

ST-220: internal sounder with one piezo speaker

Internal signal

I use an internal red light like this one, fix up my door, to know if the alarm is active

Sensors

CTC047: magnetic contact for the door

IMPACTOR: a smart shock sensors for the door In built adjustable analyzer

• Normal latching and non latching setting
• Wide dynamic range of sensitivity with High-Low sensitivity setting.
• Pulse count options, one or two pulses.
• Power on reset
• Requires 12 VDC
• NC relay and red led indicator

White color, dimensions 21 x 26 x 87 mm

Alarm module

• board bottom view (1)
• board bottom view (2)
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This module use these components:

• PIC 16F877A Enhanced Flash microprocessor
• RM4SHR-M 4 channel Rolling Code Superheterodyne Receiver Module with decoder
• 3 x BC337 transistor
• 3 x 12v pcb rele'
• 3 x red micro leds
• 1 x microswitch 2 way 2 positions
• LM317 Adjustable Regulator
• 7805 Positive Voltage Regulators
• Battery 12v 20Ah
• 3 x 1N5406 diodes
• 5 x 1N4004 diodes
• 3 x micro red led
• 1 x red led
• 1 x blue red
• `4 x 560ohm 1/4w
• 3 x 4700ohm 1/4w
• 3 x 10Kohm 1/4w
• 1 x 220ohm 1/4w
• 1 x 1Kohm 1/4w
• 1 x 1Kohm orizziontal trimmer
• 2 x 18pF ceramic capacitors
• 1 x 20MHz quartz
• 1 x 0.1uF 63v poliester
• 2 x 100uF 25v electr. capacitor.
• 1 x 4700uF 35v electr. capacitor
• 1 x Toroidal transformer 12v-0-12v 50VA

1 x 28 pin socket

Many of these components are easy to find in any electronic shop

The blue led connected to the pin RA3 of microcontroller is used like a memory to know if the alarm has been activated by an event and its reset after a reactivation.

The red led connnected to the power supply before the 1N5406 diode is used to check the power supply connection.

Offcource the other 3 microled red near the relais are used to check the output state.

Alarm module firmware

To program the 16F876A Microchip microcontroller I have used the PICKIT 2 USB Development Programmer/Debugger (cod. PG164120 or DV164121) with a cost about 40-50$.

I love the C language because it is very simple if compared to assembler.

The my C source has been compiled with HI-TECH PICC-Lite^™ Compiler.

HI-TECH Software has provided a freeware HI-TECH PICC-Lite compiler as a tool for hobbyists and students, but the licence allows its use for commercial purposes as well. It is ideal as a teaching tool for an introduction into the 'C' language and embedded programing on a Microchip device.

Here you can download the last version 10 July 2007

• source
• binary (hex)

Installation