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--- comfilepi:controlling_the_piezo_buzzer:index [2022/12/01 11:46]
COMFILE Technology [Python Example]
+++ comfilepi:controlling_the_piezo_buzzer:index [2023/06/26 08:43]
COMFILE Technology [Controlling the Electro-magnetic Buzzer]
@@ Line 1: / Line 1: @@
+====== Controlling the Electro-magnetic Buzzer ======
+The CPi-A/B/C/S series panel PCSs have a built-in electro-magnetic buzzer. By default, it beeps when the screen is touched.
+===== Enabling/Disabling the Touch Beep =====
+To disable the touch beep, simply execute the following commands:
+<code>
+sudo systemctl stop touch-beep.service
+sudo systemctl disable touch-beep.service
+</code>
+To enable the touch beep, simply execute the following commands:
+<code>
+sudo systemctl enable touch-beep.service
+sudo systemctl start touch-beep.service
+</code>
+===== Programming the Electro-magnetic Buzzer =====
+The electro-magnetic buzzer is tied to GPIO pin 30 on the CPi-A and CPi-B panel PCs and GPIO pin 27 on the CPi-C panel PCs.  One way to program it is to use the [[http://abyz.co.uk/rpi/pigpio/|pigpio library]].  The following examples illustrate how to use a programming language to play a beep.
+==== C++ Example ====
+<code C++>
+#include <pigpiod_if2.h>
+#include <thread>
+using namespace std;
+#define PIN 30  //  CPi-A/B/S
+//#define PIN 27  //  CPi-C
+int main()
+{
+   auto instance = pigpio_start(NULL, NULL);
+   // We actually can't achieve 2700Hz due to the sampling
+   // rate, but it will do the best it can
+   set_PWM_frequency(instance, PIN, 2700);
+   // 128/255 = 50% duty
+   set_PWM_dutycycle(instance, PIN, 128);
+   // play beep for 100 milliseconds
+   this_thread::sleep_for(chrono::milliseconds(100));
+   // turn off beep
+   set_PWM_dutycycle(instance, PIN, 0);
+   pigpio_stop(instance);
+   return 0;
+}
+</code>
+Compile with:
+<code>
+g++ playbeep.cpp -lpigpiod_if2 -o playbeep
+</code>
+==== Python Example ====
+<code python>
+import time
+import pigpio
+PIN = 30  # CPi-A/B/S
+# PIN = 27  # CPi-C
+pi = pigpio.pi()
+# We actually can't achieve 2700Hz due to the sampling
+# rate, but it will do the best it can
+pi.set_PWM_frequency(PIN, 2700)
+# 128/255 = 50% duty
+pi.set_PWM_dutycycle(PIN, 128)
+# play beep for 100 milliseconds
+time.sleep(0.100)
+#turn off beep
+pi.set_PWM_dutycycle(PIN, 0)
+pi.stop()
+</code>
+[[comfilepi:index|ComfilePi - Industrial Raspberry Pi Panel PC]]

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