Please go to the Menu section, create a menu and then select the newly created menu from the Theme Locations box from the left.

Tone Maker

Tone Maker is an ATmega328p-based Arduino Uno-compatible square-wave generator designed specifically to take the place of an expensive function generator to drive a small 8-ohm speaker for resonance experiments in my physics courses. The default program generates audio frequencies corresponding to C4 (middle C on a piano), D4, E4, F4, G4, A4, B4, and C5. A push-button interface allows a user to rotate through this octave of frequencies and a seven-segment display shows which note is currently being produced. A barrel jack accepts battery power ranging from 9 V to 12 V. A slider switch provides two output volume levels, and banana plug jacks allow easy speaker hookup. An 6-pin ICSP header is provided so the MCU can be reprogramming using the Arduino IDE and a programmer like the AVRISP mkII.

2014-09-19 09.55.38

Tone Maker R2 Parts List

1 x Tone Maker R2 PCB – Purchase from Tindie (link)

The following parts are available at Mouser using the included links.

1 x 28-pin DIP Atmel ATmega328p Microcontroller (link)
1 x 28-pin DIP socket (link)
1 x 7805 5-V linear voltage regulator (link)
1 x Lite-On 4301-package 7-segment display (link)
1 x 16 MHz Crystal (link)
1 x SPST tactile switch/button, normally open, momentarily closed (link)
1 x SPDT slide switch (link)
1 x 2 rows, 6 positions header (link)
1 x female 2.1 mm barrel jack (link)
1 x black female banana plug jack (link)
1 x red female banana plug jack (link)
1 x 300 ohm resistor, 0.25W (link)
7 x 110 ohm resistor, 0.25W (link)
2 x 100 kohm resistor, 0.25W (link)
2 x 22 pF ceramic capacitor, 100V (link)
1 x 0.1 microF ceramic capacitor, 50V (link)
1 x 0.33 microF ceramic capacitor, 50V (link)


Circuit Schematic
Example Arduino Sketch

Creative Commons License
Tone Maker R2 by Jeffrey Groff is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Based on a work at

Author Description