4630/WisBlock Not Seeing Ultrasonic Distance Sensor

Evb111 · April 24, 2026, 3:56am

What product do you wish to discuss? RAK4630/Wisblock
What firmware are you using? Meshtastic
What firmware version? 2.7.15
Computer OS? Windows

Hi, I’m trying to get the RCWL9620 (https://www.digikey.com/en/products/detail/m5stack-technology-co-ltd/U098-B2/15839048) ultrasonic distance sensor to work with my RAK 4630 wisblock board. In the meshtastic docs, it says it’s a supported sensor. I’m just curious if they work together, and what I need/what I need to connect it to on the board. Thanks! (Hopefully this is the right place to ask this)

carlrowan · April 25, 2026, 4:54am

Welcome to RAK forum @Evb111 ,

Most of telemetry sensors of Meshtastic uses I2C. This simplifies integration - Telemetry Module Configuration | Meshtastic

I am not sure if that module supports I2C. As I look at it, it seems not.

Evb111 · April 25, 2026, 4:24pm

Ah, I got the I/O version, and not the I2C. That’s probably my problem! What would be the right pin holes to put the I2C version in?

carlrowan · April 26, 2026, 2:00am

The I2C header has label at the back of the baseboard.

Evb111 · April 26, 2026, 2:55am

Alright, thanks for your help!

Evb111 · April 28, 2026, 8:39pm

I just got it connected, and when I boot the 4630, the green light on the board turns off, and I can’t connect to it via bluetooth or serial. Anything I’m doing wrong?

carlrowan · April 29, 2026, 6:11am

If the green light is off, you can check if the 3.3v is present. It can be that there are some short circuit caused by the connection you did.

Evb111 · May 1, 2026, 2:00am

I measured the voltage off of the VDD and the GND header, and also at the sensor connection point, and there is 3.3 volts at all the points I checked.

carlrowan · May 3, 2026, 10:58pm

Is the RAK4630 still detected as COM port? Can you upload FW but only no serial connection?

If it is still detected as COM port then the bootloader is still ok. If not, you can try to double click reset to force DFU mode.

Evb111 · May 4, 2026, 4:00am

It still shows up as a COM port.

carlrowan · May 4, 2026, 12:39pm

If you can still establish connection to it via USB/Serial, you can check the serial logs and see if there is any clue we can get.

As for the Ultrasonic Sensor, I am not sure if that is fully supported by default by Meshtastic.

Evb111 · May 4, 2026, 2:06pm

When I open the serial monitor, it only works when the sensor is disconnected. When I connect it and reboot, no logs come through, but it does still show up as a COM port.