Piezo element

Internal GPIO handling NORMAL

../_images/P000_Piezo_element_RTTTL_1.jpg

Introduction

RTTTL (Ring Tone [Text] Transfer Language) was developed by Nokia to play more “easy on the ear” melodies as ringtones for mobile phones. The tunes over all characteristics are created by using three different commands:

d - duration

o - octave

b - tempo (beat)

After that the actual tune is then created using standard notes (a, b, c, d, e, f, and g), before the note the duration is set, after the note the octave is set:

<duration><note><octave>

To compose a jingle you separate the notes with a comma.

Specifications:
  • Output sound

Wiring

ESP              Piezo
GPIO     <-->    Positive (red)
GND      <-->    Negative (black)

Setup

No device is needed, generally you use rules to activate different notifications, or you send commands to activate them. Below you find more information on how to do this.

Rules examples

From ESP Easy v2.0.0 its possible to play melodies via RTTTL (don’t forget to remove the spaces and replace # with -, this might be fixed in future releases):

http://<ESP IP address>/control?cmd=rtttl,14:d=4,o=5,b=112:8a,8a,a,8a,8a,a,8a,8c6,8f.,16g,2a,8a-,8a-,8a-.,16a-,8a-,8a,8a.,16a,8a,8g,8g,8a,g,c6

This plays a melody on pin 14.

You can also use these from rules. We use it to let our alarm system give feedback to the user via a piezo speaker.

To make a boot-sound on startup, create a rule like this:

On System#Boot do
  rtttl,14:d=10,o=6,b=180,c,e,g
endon

A place to find more tunes, all saved as txt files.

Besides RTTTL it’s also possible to play a single tone on a pin, via a buzzer, speaker or piezo element:

http://<ESP IP address>/control?cmd=tone,14,1300,200

Plays a 1300 Hz tone for 200 ms on GPIO-14.

Commands

Internal GPIO handling NORMAL

Supported hardware: Buzzer (RTTTL), Piezo element, Speaker (Ringtones etc.)

Command (GPIO/Value)

Extra information

tone,<gpio>,<tone>,<duration>

GPIO: 12 … 16

Tone: 20 … 13000 Hz

Duration: 100 … 15000 msec

You should try to use GPIO 12…16 since these generally aren’t used. The recommended tone range is 20 Hz … 13 kHz. Up-to 40 kHz should be possible to generate, but will be inaudible for humans. Frequencies above 30 kHz are not stable and will likely crash the ESP.

Duration is set in ms.

N.B. tones with a duration less than 50 msec will be blocking. Longer duration will use the scheduler, which may cause some fluctuations in the duration.

rtttl,<gpio>,<value>

GPIO: 12 … 16

Value: d=<duration>,o=<octave>,b=<tempo>,<notes…>

You should try to use GPIO 12…16 since these generally aren’t used by ESP internal functions. N.B. Playing a tune is blocking for as long as the tune is playing.

Value can be defined like <name_of_melody:duration,octave,beat,notes….>

For example: rtttl,14,test:d=8,o=5,b=180,c6,b,c6,p,g,g-

More RTTTL Ringtone Downloads

Where to buy

Store

Link

AliExpress

Link 1 ($)

$ = affiliate links which will give us some money to keep this project running, thank you for using those.