VMR6512 HIFI Audio Transmition Board

General Description

This is a simple board designed to demonstrate the basic function of V-Module’s HIFI Audio FM transmitter. It has a power connector, a stereo earphone jack and two buttons. Power supply is connected to the power connector, the voltage must be 2.7V-3.6V. The audio signal is input from the earphone jack. 2 buttons are used to adjust the working frequency of the board. Each time the UP/DOWN button is pressed, the working frequency will increase/decrease 0.1MHz. It’s extremely easy to build some garget like in-car MP3 transmitter or in-house audio transmitter with this small board.

 Characters

* Supply voltage: 2.7-3.6v
* Working current: <40ma
* RF Power: 115dBuV
* Working frequency: 76.0-108.0MHz
* Transmitting range: >50m (open area, 75cm antenna, 100MHz)
* Board size: 46mm x 30.5mm x 18mm
* Weight: 12g

User instruction

* Power Connector:    2.7-3.6V DC power input.
* Stereo Jack:  3.5mm jack,  Stereo audio input.
* External Connector:    external pins used to control the on-board VMR6512 by external controller.
* Button UP/DOWN:   Buttons used to change the working frequency of the board. Each time they are pressed down the working frequency will increase/decrease
0.1MHz.
* Antenna pad:   RF output. Simply connect a wire to this pad. Optimized length is 1/4 wave length of working frequency, for example, 75cm for 100.0MHz

Notes

* Default working frequency is 100.0MHz
* When up/down button are pressed simultaneously, the working frequency will be reset to 100.0MHz.
* Do Not power the board with voltage higher than 3.6V. If a li-on battery is used, an 1N4148 diode(or other silicon diodes) should be connected between the battery and the VCC pin of the power connector.