Protection from theft with a simple electronic key

When it is necessary to protect an object, people come up with different methods of protection. They hang padlocks, put code locks, put up howler bells.

I decided to make my contribution to such devices. More precisely, I came up with an actuator. They, in turn, can turn on the solenoid. This device can be used to turn on lights or something else.

The design is very simple. You can repeat it without problems.

Parts and materials

For the design you will need:

• - RG45 socket;
• - RG45 cable connector;
• - 12 volt relay;
• - battery;
• - wires, soldering iron.

Making simple protection

I have a socket from an old router, I soldered it on occasion. You can buy it in China or remove it from an old motherboard. Later I thought that it was necessary to desolder from the motherboard, there is still LEDs (would be useful for indicating the operating mode).

I cut the cable connector off the old cable. You can crimp a new one, but I had an old wire lying around, so I took it. And as a model of accessibility, not everyone has a cable crimping tool. You need two of them in total. It's probably not difficult to get a cable from the router.

I removed the relay from the old board.Initially, the circuit was designed for a two-pole relay.

But access turned out to be single-pole. Not important. I will provide more details later.

The scheme is simple. Jumpers in the main device and jumpers in the key can be closed in random order. The diagram shows the contacts of a two-pole relay. But since I have one pole, the diagram shows a jumper of one group.

We close the wires on the key according to the diagram. If you take the connector with the wires toward you and the key down, then the contacts are reported from right to left. We protect the wires and temporarily twist them. We bite off the excess wires.

We assemble the actuator into a single structure. Don't forget about the jumpers and the wire going to the second pin of the RG45 connector. Connect the power.

We are testing. I used an LED light bulb as a controlled device.

Now we simulate an emergency power outage, the battery is dead or the power is turned off. Unsolder the wires from the battery. Why is the wire going to the second pin of the connector needed? Using it, we supply plus from an external device to our relay.

Take the second RG45 cable connector. We temporarily solder it to the battery, which served to power the main device. As shown in the diagram, we close contacts 1 and 8 and solder them from to minus. We solder the second contact to the positive of the battery.

This key also serves as a master key and is used in an emergency situation.

Just insert it into the socket, the relay is activated and turns on the light bulb. Well, or in real life it will unlock the door lock of a protected premises, for example.

We solder the key wires and insulate them. We make a loop of wire and shrink it with heat shrink tubing.

This is the actuator we got.This is just the basis of the design, where and how to apply it is up to everyone who assembles it. I will use it to unlock the door in the workshop.

Watch a video of the device working and manufacturing