Hello, friends the inhabitants of our site!
Until recently, I lived in a house where the land was not fenced. Now you understand what is at stake. Everything that was planted on it was available to all nearby neighbors. So half of the harvest was collected by everyone who was not lazy. And to block a plot of 15 acres was not so simple. I found another way out - assembled a watchdog. And it really helped me.
How does it work? It's common electronic a relay on transistor V2, between the base and emitter of which (terminals X1 and X2) a security loop is connected. It is indicated in the diagram by a wavy line. This is an ordinary copper wire with a diameter of 0.1-0.2 mm, for example, PEV -1 0.1, stretched along the border of the protected object. The resistance of such a wire is 1.5-2 Ohm per linear meter. I pulled this wire between 50-70 cm high wooden pegs driven into the ground. At this height, a person usually breaks it off, not cats and dogs. The wire is very thin and almost invisible, and even at night and even more so. While the loop is intact, the transistor is closed. And as soon as it is torn off, an alarm immediately triggers (in my case, a call). The device diagram is shown in the photo.
To assemble this device, we need the following materials and tools
It: step-down transformer 220 / 12V, diode bridge KTs-402E or diodes D226 -4 pcs, toggle switch, electrolytic capacitor 1000 uF * 40v, for a call to 80V (from a TA-57M phone) you need a paper capacitor of the brand MBGP at 0.5 uF * 400v, KT 815A- transistor for circuit power supply, MP 25 transistor, 0.5 W 360 ohm resistor -1 pc, 47 kom - pc, Relay that reliably operates from 9 v (I have TKE21 PDT), 5 pin tape recorder “Mom” connector - 1 pc., D814V Zener diode - pcs., power cord with plug, mounting plate.
Instruments: soldering iron, solder, tweezers, mounting wires, wire cutters, pliers, small angles for attaching the case -3pcs, M3 screws and nuts, small case, multimeter, screwdrivers.
We assemble as follows:
Step 1. We check all the radio components for operability with a multimeter. After that, we fix the transformer, relay, paper capacitor, toggle switch, 5-pin connector, bell in the case.
Step 2. We solder all the radio components on the board. We install it also in the case, solder the whole circuit to the end.
Check the correct assembly.
Step -3. We are setting up the device. The output of the power supply should be 9 in. We select the resistor R2, when the loop is disconnected, relay K1 should reliably operate. When establishing, instead of a loop, you can connect any thin wire.After we have made sure that the relay operates reliably, we connect any wire 20-30 cm long to the terminals “X1 and X2”. The transistor should close and the bell will turn off. If everything is as I wrote, then the adjustment is over.
Step -4 . We collect everything in the case and check the device is already connected with a loop.
I used a wire for a loop from any small-sized relay.
That's all, the gatekeeper is assembled. Thanks to this homemade product, I discouraged the bad people who collected our harvest of vegetables and fruits.
I wish you all success in your work! See you again.