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piezoelectric speaker


Using a Piezoelectric Speak with ESP8266

These small speakers are passive,( they dont need an amplifier), so are easy to use.

To buy- just search for "piezoelectric speaker" on ebay 

I found that the speaker would work with just GND and D2 connected, but at higher volumes would just glitch out. Connecting the 3.3V  may be better as it can allow a higher current, although I dodnt notice any issues.


Connecting the signal wire to D3 (GPIO 0) or D4 (GPIO 2) will cause errors on starting the module in some cases , so best avoid these depending on your module.
The ESP has the ability do do Pulse Width Modulation on all IO pins.


This allows the generation of square waves of different frequencies and amplitude.

This code should play some mario inspired sounds.


CODE: xxxx.bas
'Peizo Speaker demo

D0=16:D1=5:D2=4:D3=0:D4=2:D5=14:D6=12:D7=13:D8=15:D9=3:D10=1

' Use D2 (GPIO 4) for PWM

'The sound data, in format length of note, frequency
Data 12,2637,12, 2637,12, 0,12, 2637,12,0, 12,2093,12, 2637,12, 0,12,3136,12, 0,12, 0,12,  0,12,1568,12, 0,12, 0,12, 0
data  12,2093,12, 0,12, 0,12, 1568,12,0,12, 0,12, 1319,12, 0,12,0,12, 1760,12, 0,12, 1976,12,0,12, 1865,12, 1760,12, 0
data   9,1568,9, 2637,9, 3136,12,3520,12, 0,12, 2794,12, 3136,12,0,12, 2637,12, 0,12, 2093,12,2349,12, 1976,12, 0,12, 0

data  12,2093,12, 0,12, 0,12, 1568,12,0,12, 0,12, 1319,12, 0,12,0,12, 1760,12, 0,12, 1976,12,0,12, 1865,12, 1760,12, 0

data  9,1568,9, 2637,9, 3136,12,3520,12, 0,12, 2794,12, 3136,12,0,12, 2637,12, 0,12, 2093,12,2349,12, 1976,12, 0,12, 0

data   12,262,12, 523,12, 220,12, 440,12,233,12, 466,6, 0,3, 0,12,262,12, 523,12, 220,12, 440,12, 233,12, 466,6 0,3,0
data  12,175,12, 349,12, 147,12, 294,12,156,12, 311,6, 0,3,0,12,175,12, 349,12, 147,12, 294,12,156,12, 311,6, 0
data  6,0,18, 311,18, 277,18, 294,6,277,6, 311,6, 311,6, 208,6,196,6, 277,18,262,18 ,370,18, 349,18, 165,18, 466,18, 440
data  10,415,10, 311,10, 247,10,233,10, 220,10, 208,3,0,3, 0,3,0,12,-1



do
  read l,f  'Get length and frequency of note
  if f > -1 then ' if a is -1 then thats the last note, ans stop
    if f = 0 then
      pwm(D2)=0  ' if frequency zero then set output to zero as we cant do a pwmfreq of zero as it may cause a crash.likely to be fixed in later versions.
    else
      option.pwmfreq f   'set the PWM frequency
      pwm(D2) = 100 ' this is volume  0 to 1023 , 1023 being the loudest .I found at about 100 I got a loud sound and going high made little difference, ocer 950 started getting quieter.
    end if
  end if
  pause (15*l)  'pause for 15 milliseconds * l  (length of note). Reducing 15 will make it play faster.
loop until f = -1
end
Č
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