Download PCB and component layout PDFs: click here
Download source code for the fm receiver circuit: click here
Searching/changing the frequency. Switches S1 and S2 are used to change the station/channel search or switch to auto-scan mode. Search-up or search-down operation depends on the switch pressed. The 7th bit of 3rd byte in write operation is for search-up or search-down operation. The implementation of these operations has been included in the code.
R1 and R2 are pull-up resistors connected at digital pins 7 and 8 of Arduino board, respectively.
Construction and testing
An actual-size (Arduino shield type), single-side PCB for Arduino FM receiver circuit is shown in Fig. 5 and its component layout in Fig. 6. Assemble the components on the recommended PCB to avoid assembly errors. Double check for any overlooked error. TEA5767 is to be mounted on solder-side of the PCB.
A 75cm (wavelength/4) hookup wire antenna should be connected at pin 10 of the TEA5767 module.
Switch on the fm receiver circuit and use switch S1 or S2 to change frequency. Pressing S1 momentarily increases the frequency and S2 decreases the frequency. Long pressing of any of the two switches will enable auto scanning.
LCD1 shows the selected frequency, signal strength and whether the sound is mono or stereo.
To test the fm receiver circuit for proper functioning, first verify the correct voltages at various points as given in the test points table.
The author is a final-year student of B.Tech (ECE) from Truba Institute of Engineering & IT, Bhopal (MP)