Buzzer 18001 overheats on WisMesh Pocket v1

UniqueNoSpaces · May 7, 2025, 7:07pm

Please include the following information, in order for us to help you as effectively as possible.

What product do you wish to discuss? 19026 (Wismesh Pocket v1) + 18001
What firmware are you using? Meshtastic 2.6.4
How often does the problem happen? Always
How can we replicate the problem?

connect the 18001 buzzer in slot B
power on the board

Hello, I purchased 2 buzzers 18001 for my WisMesh Pocket v1’s. Problem is as soon as I power on the device, after connecting the buzzer on slot B, the buzzer smells and overheats.

I didn’t test if it sounds because of fear of letting it burn out. Also, I can’t use another slot because of the presence of the display.

I tried the following, to no avail:

changed the PWM GPIO from the default 36 to 2
set pin active = high
activated and deactivated the external notification module, it overheats regardless
swapped between the two modules

I also searched this forum and Meshtastic’s but it seems that no one incurred in the same problem.

Please help me understand the issue.
Best regards.

beegee · May 8, 2025, 3:11am

The problem with the RAK18001 in Slot B is that WB_IO2 is controlling the buzzer.
But if WB_IO2 is set to high to enable power for other modules, the buzzer gets a permanent HIGH on its control pin which leads to the overheating.

On the old WisMesh Pocket I am afraid you can’t use the buzzer.
The newer WisMesh Pocket have Sensor Slots C and D and there would be no such problem.

UniqueNoSpaces · May 8, 2025, 6:07am

What other modules could be? There is none I can see, even on slots C and D, that are under the OLED.

As an experiment, could I temporarily connect the buzzer to slot A, even if there’s no fixing screw?

beegee · May 8, 2025, 6:29am

V2 boards have no Sensor Slots under the display, we reduced the slots to two and put them on the other side.

V1 board (called VA internally):

V2 board (called VC internally)

You can put the buzzer on the Slot A, just don’t shake your end device too much.

UniqueNoSpaces · May 8, 2025, 6:40am

Great! And is it correct that i have to follow the attached table in order to get the right pin number in the Meshtastic firmware? So Slot A => WB_IO1 => GPIO 17?

github.com

RAKWireless/RAK-nRF52-Arduino/blob/cc4b1bf417541ae4e4b8afb96b4f4e7ff438f355/variants/WisCore_RAK4631_Board/variant.h#L42


      
          *----------------------------------------------------------------------------*/
          
          #include "WVariant.h"
          
          #ifdef __cplusplus
          extern "C"
          {
          #endif // __cplusplus
          
          	/*
          * WisBlock Base GPIO definitions
          */
          	static const uint8_t WB_IO1 = 17;	   // SLOT_A SLOT_B
          	static const uint8_t WB_IO2 = 34;	   // SLOT_A SLOT_B
          	static const uint8_t WB_IO3 = 21;	   // SLOT_C
          	static const uint8_t WB_IO4 = 4;	   // SLOT_C
          	static const uint8_t WB_IO5 = 9;	   // SLOT_D
          	static const uint8_t WB_IO6 = 10;	   // SLOT_D
          	static const uint8_t WB_SW1 = 33;	   // IO_SLOT
          	static const uint8_t WB_A0 = 5;		   // IO_SLOT
          	static const uint8_t WB_A1 = 31;	   // IO_SLOT

beegee · May 8, 2025, 6:47am

Each slot has two GPIO’s.

RAK18001 in Slot A would use WB_IO1.

If you have Excel, the WisBlock IO Pin Mapper can show you which GPIO is used in which slot for the different modules.

UniqueNoSpaces · May 8, 2025, 8:06am

Well, turns out I’m tired I confused 34 with 36 because the GPIO field in the Meshtastic firmware was prefilled with 36. After changing it to 34, the buzzer works fine on slot B