User Manual

3. Orangutan Buzzer: Beeps and Music

The OrangutanBuzzer class and the C functions in this section allow various sounds to be played on the buzzer

of the Orangutan LV, SV, SVP, X2, and 3pi robot, from simple beeps to complex tunes. The buzzer is controlled

using one of the Timer 1 PWM outputs, so it will conflict with any other uses of Timer 1. Note durations

are timed using a Timer 1 overflow interrupt (TIMER1_OVF), which will briefly interrupt execution of your

main program at the frequency of the sound being played. In most cases, the interrupt-handling routine is very

short (several microseconds). However, when playing a sequence of notes in PLAY_AUTOMATIC mode (the

default mode) with the play() command, this interrupt takes much longer than normal (perhaps several hundred

microseconds) every time it starts a new note. It is important to take this into account when writing timing-

critical code.

Note that the Orangutan X2 uses its auxiliary microcontroller to control the buzzer. The firmware on this

microcontroller duplicates the play_note() and play_frequency() functionality of this library, so it is possible to

play music on the Orangutan X2 without using Timer 1 (see the Section 15 for Orangutan X2 functions). The

OrangutanBuzzer library functions call the appropriate functions in the OrangutanX2 library, so they produce

the same results on the X2 as they do on the other Orangutans, and they use Timer 1 to achieve the proper note

durations.

This library can be used with the Baby Orangutan if one pin of an external buzzer [https://www.pololu.com/product/

1261] is connected to pin PB2 and the other pin is connected to ground.

For a higher level overview of this library and example programs that show how this library can be used, please

see Section 3.b of the Pololu AVR C/C++ Library User’s Guide [https://www.pololu.com/docs/0J20].

Note: The OrangutanServos and OrangutanBuzzer libraries both use Timer 1, so they cannot

be used together simultaneously. It is possible to alternate use of OrangutanBuzzer and

OrangutanServos routines, however. The servos-and-buzzer example program shows how this

can be done and also provides functions for playing notes on the buzzer without using Timer 1 or

the OrangutanBuzzer functions.

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