tuxmain/alarmclock
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Fix buzzer volume

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This commit is contained in:
Pascal Engélibert 2022-09-10 19:13:23 +02:00
commit 43921bc4f2
Signed by: tuxmain
GPG key ID: 3504BC6D362F7DCA
4 changed files with 92 additions and 92 deletions
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README.md
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@ -12,7 +12,9 @@ Arduino alarm clock with binary matrix LED display and capacitive touch buttons.
## Notes
A NE555 is used for generating a high-frequency PWM signal, feeding one 74HC's "Output Enable" port. This is because otherwise the LEDs are too bright, and playing with the serial signal to reduce brightness is not fast enough (it produces a perceptible blinking). Also, using the Arduino's internal PWM causes the serial transmission to behave erratically. And of course, as 74HC uses logical gates, it needs a binary (PWM) signal, not analog.
A NE555 is used for generating a high-frequency PWM signal, feeding one 74HC's "Output Enable" port. This is because otherwise the LEDs are too bright, and playing with the serial signal to reduce brightness is not fast enough (it produces a perceptible blinking). Also, using the Arduino's internal PWM causes the serial transmission to behave erratically (because of timers interfering with transmission, and because frequency is too low). And of course, as 74HC uses logical gates, it needs a binary (PWM) signal, not analog.
D5 is used for the buzzer because its PWM frequency is greater than other pins.
## TODO
@ -21,11 +23,11 @@ A NE555 is used for generating a high-frequency PWM signal, feeding one 74HC's "
* multiple alarms
* date (at least weekday)
* connection with online timetable?
* progressive alarm ringing
* capacitive sensing causes LED matrix to flicker
* better calibrate display PWM
* light sensor for display PWM
* save alarm time & automatically retrieve time from network or RF
* alarm auto-stop
## License