[Bug]: RAK18001 buzzer very quiet - solution included

[tropho23]

Category

Other

Hardware

Rak4631

Firmware Version

Any

Description

I found out why the RAK18001 buzzer is so anemic and quiet! It's actually not...it's because we use the Arduino 'tone' command and not PWM.

This explains a few things:

1. Why it's so quiet
2. Why it gets really hot (burns your finger) when operating for more than ~1 second
3. Why it makes the RAK5005 die with the GPS module (or likely any other) installed

For #1, it's just the nature of the buzzer; it's a PWM buzzer and using the 'tone' command is not how to make it work well For #2, same as above due to how PWM works versus constant voltage For #3, same as #2 but the very high current draw causes a brownout condition on the RAK5005 that was resolved due to power circuit redesign for the RAK5005 and RAK19003

I have not tested this but a user on the RAK community forums has: https://forum.rakwireless.com/t/buzzer-rak18001-weak-audio-output/10014

The submitter provided sample code to use the buzzer in PWM mode vs. 'tone' command and found the RAK18001 is plenty loud, doesn't get crazy hot while operating, and does not cause RAK5005 failure when other sensor modules are installed.

Relevant log output

No response

[noon92]

Tropho, was this solved by the PWM toggle in settings? For me the sound is very quiet, but it's not heating up.

[tropho23]

PWM is required to make passive buzzers work at all, so it's not really a solution. I suppose the best solution is to use a different buzzer, but that requires a GPIO we might not have unless a RAK13002 is added.

Tony Good

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From: nagumii @.> Sent: Thursday, April 18, 2024 08:44 To: meshtastic/firmware @.> Cc: tropho23 @.>; Author @.> Subject: Re: [meshtastic/firmware] [Bug]: RAK18001 buzzer very quiet - solution included (Issue #3244)

Tropho, was this solved by the PWM toggle in settings? For me the sound is very quiet, but it's not heating up.

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