BuzzerShield < AFNOG

---+ The Buzzer shield
---++ The Hardware

The buzzer shield implements a passive buzzer with frequencies up to 1 kHz - 3 kHz. By default it uses data line D5 corresponding to GPIO 14 but can be configured to a different GPIO line.

<img alt="wemosBuzzer.png" src="%ATTACHURL%/wemosBuzzer.png" title="wemosBuzzer.png" />

In order to make the device work a solder bridge for the data line must be installed ( see the 4 double solder blobs on the left hand side of the module. One of these pairs of blobs must be connected).
---++ The software

The buzzer needs a frequency passed to it through a GPIO line (by default the upper solder pair blobs connected corresponding to D5 or GPIO 14. To test the device I wrote a very simple micro Python script sending a 500 Hz square wave to it. This can easily be done through the micro Python PWM class.

Here is the code:

%ATTACHURL%/firstTest.py.txt

Dave Hylands has written some [[https://github.com/dhylands/upy-rtttl][micro Python buzzer scripts]] to play ringtone melodies defined in the RTTTL (<b>R</b>ing <b>T</b>one <b>T</b>ext <b>T</b>ransfer <b>L</b>anguage). These scripts are written for the !PyBoard and must be modified to run on the !WeMos D1 mini which use the ESP8266 CPU. I found another problem in the ESp8266 PWM driver code for micro Python, limiting the maximum frequency to 1 Khz, too low to play the tunes correctly. It turns out however that the driver can run at frequencies up to ~ 2 kHz and simply modifying the limit to 2 kHz solved the problem. Of course micro Python must be recompiled and re-flashed to enable these higher frequencies.

And here are the scripts playing the ringtones: esp8266Buzzer is the main program relying on the RTTTL class defined in rtttl.py and the songs on RTTTL format defined in songs.py:

%ATTACHURL%/esp8266Buzzer.py.txt

%ATTACHURL%/rtttl.py.txt

%ATTACHURL%/songs.py.txt

-- %USERSIG{UliRaich - 2019-03-22}%

---++ Comments

%COMMENT%

Attachments

Topic attachments
I	Attachment	History	Action	Size	Date	Who
txt	esp8266Buzzer.py.txt	r1	manage	0.7 K	2019-04-05 - 15:05	UliRaich
txt	firstTest.py.txt	r1	manage	0.2 K	2019-04-05 - 15:05	UliRaich
txt	rtttl.py.txt	r1	manage	3.8 K	2019-04-05 - 15:05	UliRaich
txt	songs.py.txt	r1	manage	6.2 K	2019-04-05 - 15:05	UliRaich
png	wemosBuzzer.png	r1	manage	101.1 K	2019-03-22 - 14:15	UliRaich

This topic: AFNOG > WebHome > AFNOGWorkshop2019 > WeMosD1Mini > BuzzerShield
Topic revision: r2 - 2019-04-05 - UliRaich