Alarm System Using Multiple Voice

The alarm system using multiple sound which can be a human sound or police siren, this is a useful method of keeping intruder's away from any location for example house, farms or stores. The system is capable of operating indoor or outdoor and uses PIR (motion sensor) to activate the circuit.

The system is equipped with voice recorder system that can record any sound and repeat it once it detects any motion, the user can select any sound to record and change it an desired depends on the present danger, for instance some animals can can be scarred through dog barking sound. Moreover the sound it amplified using an amplifier and can reach 120 dB sound level. The system is currently powered by 12V adapter but this source can be changed to solar system.

The system capable of operating in an indoor or outdoor environment, the system is powered through 12 V DC adapter but I can be powered by solar energy as it does not require much power in case there is no electrical source.

However once the system is powered on when motion sensor (PIR sensor) detects any movement within range of 7 to 5 meters, it triggers the voice recorder unit to single out the sound through the loud speaker. The sound level can be as high as 120 dB which is very loud and can scare any intruder such as person or large animal, the system then repeats the sound again if the PIR sensor picks up the motion.

The system consists of the following parts:

1. ISD 1820 voice recorder unit
2. TDA2050 Mono Amplifier Board
3. Voltage regulator 7805
4. Capacitors 0.33 uF and 0.1 uF
5. Big speaker as desired

The tools used for this project are:

1. Electric drill
2. solder iron
3. screw driver
4. multimeter
5. wire stripper
6. pen

The system block diagram as in the figure the 12V DC power adapter supplies power to the power amplifier TDA2050 , in addition the 12 V is stepped down to 5V by voltage regulator 7805 IC. The 5V is supplied to the ISD 1820 voice recorder and the PIR sensor. The 7805 regulator fitted with 0.3 uF and 0.1 uF capacitors this circuit is recommended in the data sheet of the regulator.

The output single from the voice recorder (signal ) is connected to the IN1 of the amplifier, and the E-P In the recorder is connected to the output of the PIR sensor.

In this step mark the points for the position of the units then mark the points using a marker pin. After that drill the points in box and fit the the units in the box. Next solder the 7805 in with the capacitors, note that using header pins are easer to improve and repair.

In this stage all the units are connected to each other, then place the PIR sensor in the front position of the box and I use plastic holders to support the PIR in position, due to heat of the environment I have made an opening in the front of the box to cruciate the air inside the unit. Then connect all the units together as in the system block diagram. Note do not connect the GRD of the recorder with the GRD of the amplifier as this will reduce the amplitude of the signal.

The system is ready to use before that disconnect the PIR Vin, then power the system ON after that press the red button on the voice recorder and record the siren sound release the button after 10 seconds. Then press play to hear the clarity of the sound repeat the last step if not. The volume can be controller through a knob in the amplifier. Then power off the system and connect the PIR Vin power and power back the system for the first one minute the PIR will be triggering the system on and off which is normal for the PIR to settle. in order to get high PIR detection the system should above ground level.

If you have any issues please send, all the best.

Best regards