Sound

The stamp can make sounds by hooking up an external, 8 ohm speaker to an amplifier controlled by a stamp pin. Here's the simplest way to do it.

Some tips:

1. Capacitor C1 is optional. It helps kill some of the hiss. Try with and without and see which you like. Use a 10 microfarad electrolytic capacitor and watch the orientation
2. V+ can be 9 or 12 V. The more the volts, the louder the sound. For most applications, 9V is fine.
3. The bigger the speaker the louder the sound (generally).
4. There is no volume control. If too loud, put a pillow over the speaker
5. Not high quality audio, but it works.

To kill some of the high frequency hiss, you can try adding a 10 uF electrolytic capacitor as shown below (watch the orientation). Try with and without and see which you like.

Software

Two Stamp commands generate sounds, freqout and dtmfout. For complete details, see the Stamp manual, available for free download from the Parallax web site.

Syntax:

freqout x, duration, note1, note2

where x = stamp pin (0-15), duration is length of tone in milliseconds, note1 is frequency (in Hz) of first note and note2 is that of the second which is played simultaneously to form a chord. The argument note2 is optional. For example

freqout 1, 1500, 500, 1000

uses Pin 1 to output a note 1.5 sec long that combines 500 Hz and 1000 Hz tones.

dtmfout x, [5,5,5,1,2,1,2]

is used to make the audio sound like telephone buttons. The example about uses pin x to "dial" the number 555-1212.

Try these two commands out and see what you get.

Here is some demo software downloaded off the Parallax web site that shows off sound capability (StampSounds.bs2).

Or, look up the freqout and dtmfout commands in the Stamp manual for more sample code.