Homemade radio call
The radio call with which door locks are opened, control various household appliances, gadgets, is gradually becoming popular among compatriots. It is easier to install, since you do not need to additionally hammer, drill walls, partitions, door panels, pull wires. This is convenient, for example, when the call is installed on the gate of the house, on the vestibule door.
There are many electronic circuits for radio calls. They have different functions, range, power sources. They have the same presence of a transmitter and a receiver of a signal. A source is usually a button, a receiver is a device that houses a music chip, antenna, and speaker.
A homemade call differs from the factory call in the frequency of signal transmission from the transmitter to the receiving device - it is 87.9 MHz. The call itself includes: a control circuit; sound chip; transmitter; source of power.
The device is controlled by a button. Pressing it turns on the transmitter, which for several seconds transmits a signal of a certain frequency. The signal is perceived by the antenna of the receiving part of the call. He launches a sound chip, which through microdynamics produces specific melodies.
A radio call can be made, for example, from a broken computer mouse. Dismantle its body, remove all the insides, leaving the contact buttons in place. The board is re-soldered a little: two keys are connected to the device making a sound; everything else can be removed.
Remove the wheel from the mouse, cut it into two parts. They return one of them to their place. They are engaged in a remote control board - they provide a sound pair with a twisted pair. With its help, the button and mouse buttons are connected.
The free ends are soldered to the contacts held by the keys. One to the edge, the second to one of the two remaining. The contact that remains free is connected with the opposite wire. This ensures that both buttons work simultaneously.
After experiencing a call.