FM transmitter radio headphones

With the advent of young replenishment in my family, the dream of a 100,500-watt multi-channel acoustic system for home theater was finally abandoned and forgotten. Movies now look in the evenings, with the muffled sound of the already weak regular TV speakers. TV remote control is not released from the hands - to dynamically adjust the volume depending on the scene.

Naturally, there was an understanding that films were probably more comfortable to watch with headphones. Considered such options:

• extender : films are watched at least together, and it is not sports, hanging wires;
• BlueTooth : you need at least two expensive headphones, and it’s not yet known whether they can be connected at the same time;
• Wi-Fi : there are two laptops and one communicator at home. I tried to set up the network broadcasting, however, the desynchronization of the sound and the image could not be defeated, the option was no longer available;
• And then I remembered that there is such a wonderful thing as a car FM transmitter .

These devices can transmit a signal in the FM-band. Sometimes they have USB, SD and, as a rule, a line input, which we need. 12V power we take from the HTPC BPU, the sound from the line-out. Receivers will serve the usual mobile phones with FM-receiver, of which in the house there were 3 pieces. Or any other compact FM receiver with headphones.

There is a large kitchen with a sofa and a 37 "LCD panel for watching movies. The distance from the sofa to the panel is about four meters. The HTPC system revives, which is also a terminal server, NAS and Wi-FI router. I will tell about this interesting device another time .
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Implementation

The transmitter was purchased on EBAY for a token amount and was dismantled on arrival on the same day. Instead of power from the cigarette lighter, the Molex connector would be soldered. This is what happened:

The USB connector is attached by the manufacturer only for powering external devices.

The transmitter was temporarily left outside the HTPC for better signal. I must say that the transmitter was bought the cheapest. If you look closely, it consists of a pair of transistors, quartz and half a dozen capacitors and resistors assembled on a trembling knee. The frequency is fixed, 88.7 MHz (set experimentally). However, there is a reception within a radius of 3-4 meters.

If% username% decides to repeat this simple scheme, I advise you to look for the most powerful transmitter, with the ability to set the frequency and normal stereo.

PS: For those who have felt deja vu, I inform you: some time ago I already published this article in the sandbox