This is a design of a Digital FM Radio controlled by the I2C protocol, integrated RTC clock and thermometer with alarm function.
Above the driver circuit, say it's self explanatory, the capacitor of 6800 uF and 100n are necessary for filtering noise in LCD pin 16 will go to the driver by the addition of LDR circuit, which is shown below. The outputs are SCL and SDA I2C outputs that are connected in module PLL FM TEA5767 and DS1307 digital clock, digital clock to use the original output of the PIC I2C so the clock is controlled by hardware, since the outputs for digital FM utilizanos 2 ports emulating common PIC I2C. This was because the chip TEA5767 not work on the original I2C output of PIC. With the I2C work properly emulated. The pin 40 excites a BC548 which controls a relay that will be used to connect and disconnect the audio amplifier, which will turn on outputs corresponding chip FM - TEA5767. Just when the alarm is triggered the relay is connected and turn on the FM also Buzzer button turns on and off this relay. For the amplifier can use the circuit presented in this site that uses the TEA2025 or any other amplifier. Also a good PC sound box can be used. The original design has a blue LED on the power amplifier which illuminates when the relay is activated and connected amplifier. The chip Fm has no power to excite a loudspeaker as already commented.
Pin 1 of the PIC must have a 10k resistor connected to VCC pin MCLR is because, if it does not, the circuit exhibits instability when disconnected the ICSP programmer (PICKIT2).
Part B of the circuit shown above, contains the FM chip, the clock RTC, and LCD brightness control done with a LDR.
The DS1307 is connected so classic, being the Led blinking clock is powered by software when the alarm is triggered, the crystal used is a standard clock crystal for easy acquisition with the frequency indicated in the circuit. at pin 3 can be added in a battery or cones 3 V, allowing the circuit to keep the counter time / date even turning off the power. The capacitor 3300UF and 100n are important to filter out noise and to prevent the chip / crossbar crystal in the case of turning off the power.
The 5767 TEA also connected in standard mode, and the pins 8 and 7 are the two stereo audio outputs, for connection of the audio amplifier, the F 1u capacitors are needed. The pin 8 is the FM antenna must be properly connected. Use a comb pin type ci, to weld the same as TEA5767 is available in SMD, for extremely fine wires so use the links because the slightest pressure on the chip will track circuit let loose rendering them useless. This chip can be found on e-bay, and can be purchased via paypal receipt by mail.
The circuit uses an LDR transistor BC548 polarized in the working region, the two trimpots are used to adjust the minimum and maximum brightness, and also serve to polarize the transistor saturation and avoiding court. Adjust circuit within the confines light / dark be wants to use the circuit. The capacitor 1500UF serves to ensure a smooth change of brightness and gradual. The LDR is common.
As a complement, we use an accountant in 4017 on two stages to create a pressure switch, the chip excites a TIP31 transistor that is capable of "drivar" up to 12-15 high brightness LEDs - creating a flashlight flash.
Below
code
utilized
in this
circuit
version
end
which was
implemented
on
mounted circuit, below last,
a code graphical version, which did not fit in the memory of the PIC so
can not be evolved with alarm functions.
We use a 4017 to make a
+ bistable pressure switch
and called a TIP31 transistor
media power that makes connecting 6-12
high brightness leds making a
flash light.