It is quite difficult to find an inexpensive burglar alarm, for example, to protect a summer cottage. The use of ready-made industrial designs in such cases can become economically unprofitable. It's time to take up the tools and make a security device with your own hands.
It is necessary
Passive infrared motion sensor, siren, batteries (batteries), battery holder, relays, insulating tubes, electric wire
Instructions
Step 1
Determine what type of burglar alarm you need. First of all, you should probably be interested in the alert about the intrusion into the protected area. The simplest such signaling device may include an infrared motion sensor and a siren. It is desirable that the signal turn on for a short time, after which it automatically turns off, going into standby mode.
Step 2
In order to mount such an alarm, you will need: a passive infrared motion sensor, a 12 V siren, batteries (batteries), a battery holder, a 6 V relay, insulating tubes, a wire.
Step 3
Open the motion sensor, remove the ball-shaped part and bend one of the supports (the halves are latched). Remove the board. The standard sensor is a passive infrared receiver that responds to changes in the amount of radiation falling on it, as well as a simple optical system. It is desirable that the sensor has a viewing angle of at least 180 degrees.
Step 4
Apply power to the sensor and connect the relay coil. Dismantle the standard relay (it is located in a black box). Connect the siren and batteries through the terminals.
Step 5
Since there is not enough space inside the ball-shaped part of the sensor, wire the relay out to the base of the case. Power is supplied through the switch to the sensor. The sensor is triggered and, with its closing contacts, turns on the siren. The relay allows you to connect several sirens to the device.
Step 6
When checking the operation of your burglar alarm, do not turn on the siren without first protecting your ears - despite its small size, the siren can cause discomfort in the vicinity up to hearing damage.
Step 7
Using the regulator on the sensor, set the operating time of the siren after the device is triggered, the range is from a few seconds to 8 minutes. Install the sensor inside the building, bring the siren outside. Bring the siren switch to a secret place and turn it on 5 minutes after turning on the sensor. It is possible to provide a car ignition lock as a switch.
