How To Make A Short-Range FM Radio Station?
This article demonstrates to you best practices to construct a little radio station at home and offer music with others. The station can likewise be utilized for making declarations in universities, enterprises, healing centers, schools and different spots utilizing a condenser mic speaker circuit.
In this venture a FM transmitter V2.0 module is utilized, as appeared in Fig. 1. It is accessible on www.ebay.com and www.amazon.in. The module can regulate your voice or music on FM radio. In the event that you have a radio recipient, you can get and hear it out.
Fig. 1: FM transmitter V2.0 module
This module speaks with Arduino Uno R3 or another microcontroller through I2C interface. All charges are sent through I2C interface. Here, Arduino Uno R3 alongside Arduino library record is utilized for offering orders to control and shift distinctive frequencies inside 88MHz – 108MHz FM band.
Circuit and working
The FM transmitter V2.0 module has the accompanying four pins:
1. Vcc (5V)
2. GND
3. SDA (serial information I2C stick)
4. SCK (serial clock I2C stick)
A standard 3.5mm male-to-male sound link (Fig. 2) is utilized for interfacing with the MP3 player, portable or PC.
Fig. 2: 3.5mm male-to-male sound link
Piece outline of the short-extend FM station is appeared in Fig. 3 and its circuit graph in Fig. 4. It is worked around Arduino Uno R3 (BOARD1), FM transmitter V2.0 module (TX1) and a couple of different segments.
Fig. 3: Block graph of FM station
Circuit graph of FM radio station
Fig. 4: Circuit graph of FM station
A basic fmtx library is utilized. It is an open source library, accessible here
Setting up contribution to FM band
Step 1. Download fmtx.cpp and fmtx.h libraries, and spare these on your PC under, say, fxtx envelope. Duplicate this organizer to Arduino\libraries envelope.
Step 2. Open fmtx_demo.ino code from Arduino IDE. Arrange it and transfer the program/outline to Arduino board.
Step 3. Interface Arduino board to a sound source like cell phone or MP3 player. You can likewise utilize a mic to transmit your voice.
Step 4. Turn on your FM beneficiary and set it to 90.1MHZ recurrence. Appreciate the music.
Step 5. Open Serial Monitor window from Arduino IDE to change the recurrence, as appeared in Fig. 5.
Fig. 5: Serial Monitor window Fig. 6: Author’s model
Step 6. You can change or set an alternate recurrence from Serial Monitor by basically entering the recurrence utilizing and image. For instance, to change recurrence to 99MHz sort &0990 in the Serial Monitor and press Enter key.
Additionally, to change recurrence to 99.5MHz sort &0995 (for recurrence 101MHz sort &1010 and for 102.5MHz sort &1025) in the Serial Monitor.
Programming
Circuit operation is finished utilizing the product (fmtx_demo.ino) stacked into the inward memory of Arduino Uno R3. The program actualizes all required functionalities incorporating dealing with client contributions with the assistance of serial port interface. The program is composed in Arduino programming dialect.
Arduino IDE 1.6.4 is utilized to arrange and transfer the program to Arduino board. The vital thing is to set any recurrence (inside FM band), as appeared in Fig. 5. In the program, default recurrence is set to 90.1MHz, as given beneath:
coast fm_freq = 90.1;
When you apply 9V control supply to Arduino board, it begins broadcasting the sound flag at 90.1MHz recurrence.
You can basically tune to a similar recurrence in the FM beneficiary or cell phone. You would now be able to tune in to music or message declarations from up to a separation of 50 meters.
Note that, an outside reception apparatus is required for FM transmitter module. Associate any metal wire to the cushion that could fill in as a recieving wire. Hypothetically, the perfect recieving wire length for 100MHz is around 75cm.
Development and testing
You needn’t bother with a PCB for this venture. Interface GND, 5V, A4 and A5 pins of Arduino board to GND, Vcc, SDA and SLA pins of FM transmitter module, separately, utilizing outer wires/jumpers.
Associate a USB link to Arduino Uno R3 for aggregating and transferring the program. Expel the link subsequent to transferring it. Associate a 9V battery/connector as power supply to Arduino Uno R3.
Interface FM transmitter V2.0 module to any sound source like MP3 player/cell phone/PC utilizing a 3.5mm sound link. Your circuit will transmit at 90.1MHz recurrence, which can be gotten by any FM radio by tuning to a similar recurrence. The creator’s model is appeared in Fig. 6.
