Thingy91x ADXL367 Motion Detection Only Triggers Once After Reboot

RE: Thingy91x ADXL367 Motion Detection Only Triggers Once After Reboot

0sleep — Mon, 09 Mar 2026 18:21:45 GMT

Hi! I also want to use this accelerometer, here is what works for me (based on the accel_trig sample in zephyr, running on a thingy91x' ADXL367)

# boards/thingy91x_nrf9151_ns.conf

```c
CONFIG_ADXL367_ACTIVITY_DETECTION_MODE=y
CONFIG_ADXL367_INACTIVITY_DETECTION_MODE=n
CONFIG_ADXL367_ACTIVITY_THRESHOLD=50
CONFIG_ADXL367_ACTIVITY_TIME=10
CONFIG_ADXL367_TRIGGER_GLOBAL_THREAD=y
```

# boards/thingy91x_nrf9151_ns.overlay

```c

/ {
    aliases {
        accel0 = &accel;
    };
};

&accel {
    status="okay";
};

```

# src/main.c

```c

/*
* Copyright 2024 NXP
* Copyright (c) 2018 Phytec Messtechnik GmbH
*
* SPDX-License-Identifier: Apache-2.0
*/

#include <zephyr/kernel.h>
#include <zephyr/drivers/sensor.h>
#include <stdio.h>

K_SEM_DEFINE(sem, 0, 1); /* starts off "not available" */

static void tap_trigger_handler(const struct device *dev, const struct sensor_trigger *trigger)
{
    ARG_UNUSED(trigger);
    printf("TAP detected==========================================================\n\n\n\n\n");

    if (sensor_sample_fetch_chan(dev, SENSOR_CHAN_ACCEL_XYZ) < 0) {
        printf("ERROR: SENSOR_CHAN_ACCEL_XYZ fetch failed\n");
    }

    k_sem_give(&sem);
}

int main(void)
{
    struct sensor_value data[3];
    const struct device *const dev = DEVICE_DT_GET(DT_ALIAS(accel0));

    struct sensor_trigger trig = {
        .type = SENSOR_TRIG_DATA_READY,
        .chan = SENSOR_CHAN_ACCEL_XYZ,
    };

    if (!device_is_ready(dev)) {
        printf("Device %s is not ready\n", dev->name);
        return 0;
    }

    trig.type = SENSOR_TRIG_THRESHOLD;
    trig.chan = SENSOR_CHAN_ACCEL_XYZ;
    if (sensor_trigger_set(dev, &trig, tap_trigger_handler) < 0) {
        printf("Could not set tap trigger\n");
        return 0;
    }

    while (1) {
        k_sem_take(&sem, K_FOREVER);
        sensor_channel_get(dev, SENSOR_CHAN_ACCEL_XYZ, data);

        /* Print accel x,y,z data */
        printf("%16s [m/s^2]:    (%12.6f, %12.6f, %12.6f)\n", dev->name,
               sensor_value_to_double(&data[0]), sensor_value_to_double(&data[1]),
               sensor_value_to_double(&data[2]));
    }
}

```

The sensitivity is just about right to not trigger while the thingy91x is sitting on my desk while I'm typing, but as soon as I pick up the device it triggers a few times.

RE: Thingy91x ADXL367 Motion Detection Only Triggers Once After Reboot

Tasos — Mon, 26 Jan 2026 07:39:07 GMT

Additionally, the AI insists that the Threshold Activity Register and Threshold Inactivity Register use a scale factor of 7.8 mg/LSB (for the +-2g range) but I could not find any reference to this value in the datasheet.

RE: Thingy91x ADXL367 Motion Detection Only Triggers Once After Reboot

Tasos — Mon, 26 Jan 2026 07:04:33 GMT

It is suspicious that there is no connection between P0.11 of the nRF9151 and INT1 of the ADXL367 in the Thingy:91X devicetree overlay. I modified the overlay to add this connection.

On the actual board, INT1 is not only connected to the nRF9151 but also to the nRF5340. I believe the corresponding nRF5340 pin is left floating. Unfortunately, this cannot be verified with a logic analyzer because there is no test point and the trace is routed on the inner layers.

RE: Thingy91x ADXL367 Motion Detection Only Triggers Once After Reboot

fbosc — Mon, 26 Jan 2026 06:44:51 GMT

There's basically no way to make it work properly. I'm expecting a solution, this should be a high priority issue. It's clearly not working and it's most definitely not a skill or effort issue. It's DOA with non proper support in the sdk

RE: Thingy91x ADXL367 Motion Detection Only Triggers Once After Reboot

fbosc — Mon, 26 Jan 2026 06:42:50 GMT

I tried all that with no success. Please fix this, it's clearly an issue on your side.

RE: Thingy91x ADXL367 Motion Detection Only Triggers Once After Reboot

Tasos — Sun, 25 Jan 2026 22:36:34 GMT

I struggle with the same issue.

RE: Thingy91x ADXL367 Motion Detection Only Triggers Once After Reboot

Kenneth — Tue, 20 Jan 2026 13:47:12 GMT

I don't have any experience with this accelerometer no, but asking AI I can find some discussions around this topic:

Try with a significant higher CONFIG_ADXL367_ACTIVITY_THRESHOLD value, if the range isn't changed in the driver, then a value of 50 could correspond to a very low value, potentially triggering continuously active.

Try to enable an inactivity with with a short timeout, so that after first motion the sensor will self-clear its awake state.

Try with ADXL367_REFERENCED_ACTIVITY_DETECTION_MODE=n.

Initially try with a very high threshold (low sensitivity) and gradually reduce the threshold runtime to see if that works.

Kenneth

RE: Thingy91x ADXL367 Motion Detection Only Triggers Once After Reboot

fbosc — Tue, 20 Jan 2026 12:22:38 GMT

Hi Kenneth,

Thanks for getting back to me. I don't have a logic analyzer, but I've already tried quite a bit of debugging.

Regarding your suggestion to try both activity and inactivity detection - I did that. Same issue - works once, then stops.

I've actually been through several iterations:

- Tried LINKED mode with both activity + inactivity enabled - still locks up

- Created a custom driver using DEFAULT mode instead of LINKED - still locks up

- Fixed the interrupt re-enable path to ensure it always runs even on errors - still locks up

The pattern is always the same: first motion event works perfectly, then nothing. Power cycle and it works once again.

I've modified the Zephyr driver's trigger handler to guarantee the GPIO interrupt gets re-enabled, and I've confirmed the STATUS register read succeeds. But after that first trigger, it's like the INT1 pin never asserts again.

What's puzzling is that the GPIO interrupt re-enable call succeeds, and the first callback worked fine. Makes me wonder if there's something about how the ADXL367 re-arms its interrupt that isn't documented.

Has anyone at Nordic actually tested continuous motion detection with this sensor? Or are there any known quirks with the ADXL367's interrupt behavior that might not be obvious from the datasheet?

I can provide logs or register dumps if that would help.

Thanks

RE: Thingy91x ADXL367 Motion Detection Only Triggers Once After Reboot

Kenneth — Tue, 20 Jan 2026 12:02:29 GMT

Hello,

I am not entirely sure what help we may provide here, it may seem as something that analog devices may need to help you with.

I guess the first question from me is whether you have measured on a logic analyzer the state of the INT1 pin? Does it indeed indicate an interrupt, or is the problem entirely on the configuration of the adxl side? If it's entirely on the adxl side, then maybe try at generating interrupts on both activity and inactivity detection.

Kenneth