Dear friend!

What you have in your hands is not a common gift, but the secret invention of the "Physical Experiments" program. It's a real security alarm!

Spy things



Safety precautions:

  • Read this text with an adult from your home.

    Everything in this gift set is safe.

    Always check the batteries before using them. If they are swollen or deformed, they must be replaced with others. The defective batteries must be taken to the nearest recycling point.

    The cables have sharp ends, be careful with them.

    The alarm you're going to put together is pretty noisy. Warn your family if you want to activate it before going to sleep.

For reference:

For millennia people kept their homes of thieves on their own. For this they had to mount the guard, they slept in turns, all this very uncomfortable. Only in the nineteenth century did humanity invent the first alarm called "the electronic Guardian". The system consisted of electromagnet, bell and cables that in case of some intervention of the delinquents joined or separated, which activated the alarm that rang the bell. If the "guardian" was connected to the telephone line, the nearest police delegation received a call.

You have in the set:

1. AA battery (finger-type) 1.5 V, which is easily replaced with any other finger-type battery.
2. Battery compartment with red (plus / +) and black (minus / -) wires
3. Wire 10 cm
4. Two round washers
5. Acoustic radiator (buzzer)
6. Twine (rope) 20 cm
7. Carton
8. Clothespin
9. Double-sided tape - 3 long strips and 4 squares.


  • 1
    Take a piece of cardboard and fold it in half.
  • 2
    Using a double-sided tape square, secure the rope to the fold of the cardboard sheet. Fold the sheet of cardboard to the end in half, so that the two halves were glued together. "Breaker" of the electrical circuit is ready.
  • 3
    Take the battery compartment and insert the battery into it so that its minus (flat end) rests on the spring.
  • 4
    Glue the battery compartment to the clothespin using a long strip of double-sided tape.
  • 5
    Take the sound emitter and remove the sticker from it (see "You have in the kit" p.5).
  • 6
    Connect the long leg of the sound emitter and the metal part of the red wire. To do this, make a loop of the metal part of the wire around the legs of the sound emitter. Take a loop with two fingers and twist it around its axis until the loop is firmly attached to the leg.
  • 7
    On the short leg of the sound emitter, fasten the metal part of the separate wire (see "What's in your kit?" paragraph 3).
  • 8
    Take the washer and fasten the second end of the same wire on it with a square of double-sided tape so that the metal part of the wire touches the washer.
  • 9
    Fasten the washer on the teeth of the clothespin (where the clothespin closes).
  • 10
    Repeat steps 8-9 with a black wire that is connected to the battery compartment.
  • 11
    Fasten the sound emitter to the clothespin using a square of double-sided tape.
  • 12
    Insert the "breaker" of the electrical circuit between the washers inside the clothespin.
  • 13
    Fix the end of the rope on the door, and the clothespin on the floor or wall with long strips of double-sided tape.
  • 14
    Wait for someone to open the door!

What happened?

  • 1
    Inside the sound transmitter there are small metal contacts that touch each other. If the transmitter is connected to electricity, then a magnetic field will appear inside it. This field opens contacts. When the contacts no longer touch each other, the magnetic field disappears, which allows the contacts to connect again. From constant closures and openings of contacts, there is a loud sound. This happens until the electric current disappears.
  • 2
    If you insert a "breaker" between the two washers, the electrical circuit opens (the electric current disappears), which leads to the disconnection of the sound emitter.
  • 3
    If you fix the rope from the "breaker" on the door, then when the door opens, the "breaker" will fly out of the clothespin, the metal washers will come together, the integrity of the electrical circuit will be restored, and you will hear a loud sound. Hooray! The alarm worked.
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