Two Features Request: Alarm Clock + Countdown about esp8266-led-shelf HOT 3 OPEN

One issue i might see is that the buzzer may not be very loud for an alarm, so you may want to look into some other audio device such as a speaker, but it'll be difficult to implement without the hardware and would need some sort of amplifier. I don't these features would be complicated to implement, however I do not have access to the hardware as I am currently abroad and wont be back until September. I could push some untested changes however it will be unstable and may not work correctly

from esp8266-led-shelf.

Yes, that was exactly my guess about the alarm volume...

I still have another option, but I need to dig for a way to activate a car stereo trough the arduino with some sort of hardware.

from esp8266-led-shelf.

A piezo buzzer would be fine if you can power it with more than 5v. However you would need some amplifier for it such as a transistor amplifier so the esp8266 3.3v logic pins can drive the 9v signal for example
https://electronics.stackexchange.com/questions/380206/how-to-make-active-buzzer-louder
Note that you should not exceed the rated maximum voltage of the buzzer, and that the transistor should be close to saturating (turning on fully) at 3.3v otherwise we wont get the full volume. Otherwise we can add another stage at 5v to try to boost the current flow into the base of the transistor (or gate of a mosfet)

from esp8266-led-shelf.