Robbers and other criminals are becoming smarter every day. Many people, like me, do not have an alarm system. And if you are not at home, then your valuables become easy prey for a criminal. You've probably heard about such an invention as lasers. If you touch them, the siren will sound. But they are very expensive. Therefore, I offer you this video instruction, which will show you how to make such a laser at home, spending no more than 1000 rubles.
Laser alarm
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