How to use DHT11 on STM32F103RB?

Mbed Studio
1

Hi, I have a project using STM32F103RB board with Mbed studio and I have been facing 1 problem with the dht11 sensor. I have tried all the libraries I could find but it seems like all the libraries I have tried have same common problem because the device I am using doesn’t have FPU.

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I really need help finding a dht11 library that is compatible with the device. I just started learning so I also don’t know how to configure the library codes to fix the problem.

2

Hello,

this error is not related to any DHT library and the error is reported by clang. It is know unsolved issue for years. So if the studio generates a bin file then just ignore this clang error or try this

Here you can found library what is 100% working -Mbed-CE Libraries & Examples (github.com)

BR, Jan

3

Hi, thanks for solution! It worked perfectly. However I got some new problem using threads. Right now I am trying to use 3 threads but it seems like only the first two initialized in order works and the third one never worked. I am not sure if it might be memory problem with the board or the configuration code in my mbed_app.json file below.
{
“target_overrides”: {
“*”: {
“target.c_lib”: “small”,
“target.printf_lib”: “std”,
“platform.minimal-printf-enable-floating-point”: false,
“platform.stdio-minimal-console-only”: true
}
}
}

4

Configuration seems be OK and not related to threads.

It can be issue around memory because F103RB has just 20KB of RAM, not sure. I do not know what operation do your threads but maybe you can try to set smaller stack size in the Thread constructor.
Thread - API references and tutorials | Mbed OS 6 Documentation

Default seems to be

Or just do it without threads.

BR, Jan

5

Hi, reducing the memory size for each thread seems to have fixed it for me so it was definitely the memory issue. Thanks!