error in dht11 sensor with nrf52832

[gautam_joshi]

hello,

i am using dht11 and nrf52832DK,

and i am using sample example from ncs SDK 2.4.0 https://github.com/nrfconnect/sdk-zephyr/tree/main/samples/sensor/dht,

and i have also change overlayfile and add this,

/ {
    dht11 {
        compatible = "aosong,dht";
        status = "okay";
        dio-gpios = <&gpio0 11 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
        dht22;
    };

build was successfull but when i see logs i got this error,    

Sensor fetch failed: -5

i try to figure out but i don't get any clue.

[AHaug]

Hi,

-5 means that no devices are found. You have added dht11 at the top while you state that the device are a dht22 at the bottom of the item. 

Try changing it from dht22 to dht11.

Kind regards,
Andreas

[gautam_joshi]

hello AHaug ,

i also try to remove that still i get the same error and i test sensor with Arduino it works perfectly.
and when i try to debug i found that in dht.c file in this dht_measure_signal_duration function i got error,but don't understand what was happen there. 

[AHaug]

gautam_joshi said:

i also try to remove that still i get the same error,

Remove what? You need to be more descriptive in what you change and please refer to links and documentation that you have been investigating by linking them.

Kind regards,
Andreas

[gautam_joshi]

hello AHaug 

sorry for that,

https://github.com/nrfconnect/sdk-zephyr/tree/main/samples/sensor/dht this is the link i want to share,

and when i try to replce dht22 with dht11 it show build error that this Property not mentioned in "aosong,dht".

then i also try with remove dht11 than again i got Sensor fetch failed: -5 this error.

[AHaug]

No worries, thank you for elaborating

In the sensor sample you link boards/nrf52dk_nrf52832.overlay you see

/ {
	dht22 {
		compatible = "aosong,dht";
		status = "okay";
		dio-gpios = <&gpio0 11 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
		dht22;
	};
};

By first replacing dht22{ with dht11{ you've created a new device. Then by not matching the item inside of the device you state that there are two devices so it is looking for a dht22 while you have it defined as a dht11.

In addition, the sensor sample uses the dht22 meaning that the configuration might not be valid for the dht11 sensor. So simply changing 22 with 11 might not work. You will need to investigate closer to see the requirement, what it is compatible with etc. 

I recommend you to have a look at https://academy.nordicsemi.com/lessons/lesson-2-reading-buttons-and-controlling-leds/ (and the other topics) to learn more about device tree and how to configure it as well as investigate the resources mentioned in the guide. And I would recommend you to have a look at https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/build/dts/index.html to see more details about how to use the device tree as well as also have a look at the Zephyr community discord found under Technical resources at https://www.zephyrproject.org/

Kind regards,
Andreas