listening birds songs is one of the best way to enjoy nature. The circuit mentioned here is a bird microphone transmitter or wireless bird listening microphone which will help you to listen the birds voices. Place it outside and hear beautfiul bird songs easily by sitting at home without any wire
connection. The circuit is basically a FM transmitter circuit which will broadcast birds sounds on your FM radio. You can also record these sounds after getting it on your FM radio.
One great quality of this RF circuit is that you dont have to change the battery once you place it on tree or some where for listening to birds. The circuit is using a 1.2 volt rechargeable battery and a 3 volt solar cell which will work as a battery charger during day time. The circuit will work for many months or years continuously until the rechargeable battery become failed. Make the circuit on a good quality PCB or veroboard and try to keep all components as near as possible and fit the circuit in a small box to make it weather proof. After completing the circuit tune your FM radio on a blank spot between 100 to 108 MHz and slightly turn the trimmer capacitor of the transmitter with a non conductive tool to tune the transmitter on your desired frequency. Try to install the circuit on the place where it will receive sun light for charging the 1.2 volt battery. Use 12 inches wire as an antenna.