Square-wave Generator 31 Hz to 8 MHz with Multi-Function-Shield

The Multi-Function-Shield offers a lot of components. For this tool we only need the buttons and the 7-Segment-Display. There is a buzzer connected to pin-3. Because buzzers can not produce the sound of a given frequency, we replace it by a mini speaker.

As there is still plenty of space in the FLASH we can even store the sound files for the digits '0' to '9' (German version only). On request, the value of the actual frequency is spoken through the same speaker.

The display has 4 digits, so only the four most significant digits of the frequency can be shown. The decimal point is set to read the frequency given in kHz.

The buttons offer these functions:
S2: frequency higher
S3: frequency lower
S1 + S2: say the frequency
S1 + S3: sound on/off

the source

contact: nji(at)gmx.de