Won't compile DHT.h

Development Tools IDE 1.x
1

Below are the relevant bits of my project code. I installed the required libraries but get the following error message when it tries to compile DHT.h. I tried the backup version (DHTkxm) with same result. I have used DHT.h successfully for years on two other computers and had no problem.

Thanks.

//Arduino Uno with RFM69 LoRa radio module
// SX1278 operating at 915 MHz
// DHT 22 temperature and humidity sensor
// COM 9

#include <SPI.h>
#include <Wire.h>
#include <LoRa.h>
#include <LiquidCrystal_I2C.h>
#inclide <DHT.h>

******error message ********
Arduino: 1.8.9 (Windows 10), Board: "Arduino Uno"

C:\Program Files (x86)\Arduino\arduino-builder -dump-prefs -logger=machine -hardware C:\Program Files (x86)\Arduino\hardware -hardware C:\Users\ricki\AppData\Local\Arduino15\packages -tools C:\Program Files (x86)\Arduino\tools-builder -tools C:\Program Files (x86)\Arduino\hardware\tools\avr -tools C:\Users\ricki\AppData\Local\Arduino15\packages -built-in-libraries C:\Program Files (x86)\Arduino\libraries -libraries C:\Users\ricki\OneDrive\Documents\libraries -fqbn=arduino:avr:uno -ide-version=10809 -build-path C:\Users\ricki\AppData\Local\Temp\arduino_build_433120 -warnings=none -build-cache C:\Users\ricki\AppData\Local\Temp\arduino_cache_572169 -prefs=build.warn_data_percentage=75 -prefs=runtime.tools.avrdude.path=C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17 -prefs=runtime.tools.avrdude-6.3.0-arduino17.path=C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17 -prefs=runtime.tools.avr-gcc.path=C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino7 -prefs=runtime.tools.avr-gcc-7.3.0-atmel3.6.1-arduino7.path=C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino7 -prefs=runtime.tools.arduinoOTA.path=C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\tools\arduinoOTA\1.3.0 -prefs=runtime.tools.arduinoOTA-1.3.0.path=C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\tools\arduinoOTA\1.3.0 -verbose E:\sketch_mar02a_LoRa_XMTR_915_mod1\sketch_mar02a_LoRa_XMTR_915_mod1.ino
C:\Program Files (x86)\Arduino\arduino-builder -compile -logger=machine -hardware C:\Program Files (x86)\Arduino\hardware -hardware C:\Users\ricki\AppData\Local\Arduino15\packages -tools C:\Program Files (x86)\Arduino\tools-builder -tools C:\Program Files (x86)\Arduino\hardware\tools\avr -tools C:\Users\ricki\AppData\Local\Arduino15\packages -built-in-libraries C:\Program Files (x86)\Arduino\libraries -libraries C:\Users\ricki\OneDrive\Documents\libraries -fqbn=arduino:avr:uno -ide-version=10809 -build-path C:\Users\ricki\AppData\Local\Temp\arduino_build_433120 -warnings=none -build-cache C:\Users\ricki\AppData\Local\Temp\arduino_cache_572169 -prefs=build.warn_data_percentage=75 -prefs=runtime.tools.avrdude.path=C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17 -prefs=runtime.tools.avrdude-6.3.0-arduino17.path=C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\tools\avrdude\6.3.0-arduino17 -prefs=runtime.tools.avr-gcc.path=C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino7 -prefs=runtime.tools.avr-gcc-7.3.0-atmel3.6.1-arduino7.path=C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino7 -prefs=runtime.tools.arduinoOTA.path=C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\tools\arduinoOTA\1.3.0 -prefs=runtime.tools.arduinoOTA-1.3.0.path=C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\tools\arduinoOTA\1.3.0 -verbose E:\sketch_mar02a_LoRa_XMTR_915_mod1\sketch_mar02a_LoRa_XMTR_915_mod1.ino
Using board 'uno' from platform in folder: C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6
Using core 'arduino' from platform in folder: C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6
Detecting libraries used...
"C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino7/bin/avr-g++" -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -flto -w -x c++ -E -CC -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10809 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR "-IC:\Users\ricki\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino" "-IC:\Users\ricki\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\variants\standard" "C:\Users\ricki\AppData\Local\Temp\arduino_build_433120\sketch\sketch_mar02a_LoRa_XMTR_915_mod1.ino.cpp" -o nul
"C:\Users\ricki\AppData\Local\Arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino7/bin/avr-g++" -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -flto -w -x c++ -E -CC -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10809 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR "-IC:\Users\ricki\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino" "-IC:\Users\ricki\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\variants\standard" "-IC:\Users\ricki\OneDrive\Documents\libraries\DHT_sensor_library" "C:\Users\ricki\AppData\Local\Temp\arduino_build_433120\sketch\sketch_mar02a_LoRa_XMTR_915_mod1.ino.cpp" -o nul
In file included from E:\sketch_mar02a_LoRa_XMTR_915_mod1\sketch_mar02a_LoRa_XMTR_915_mod1.ino:2:0:

C:\Users\ricki\OneDrive\Documents\libraries\DHT_sensor_library/DHT_U.h:36:10: fatal error: Adafruit_Sensor.h: No such file or directory

#include <Adafruit_Sensor.h>

      ^~~~~~~~~~~~~~~~~~~

compilation terminated.

Using library DHT_sensor_library at version 1.4.3 in folder: C:\Users\ricki\OneDrive\Documents\libraries\DHT_sensor_library
exit status 1
Error compiling for board Arduino Uno.

2

Hi @rickir206.

Just as you use libraries in your sketch code, some libraries use other libraries. In this case, it is necessary to install those libraries in addition to the library you are using directly in your sketch.

The "DHT sensor library" library has a dependency on the "Adafruit Unified Sensor" library. You don't have the "Adafruit Unified Sensor" library installed, so the compilation fails with this "No such file or directory" error.

You can solve it by installing the missing library.

I'll provide instructions you can follow to do that:

  1. Select Sketch > Include Library > Manage Libraries... from the Arduino IDE menus.
    The "Library Manager" dialog will open.
  2. Wait for the update to finish, as indicated by the progress bar at the bottom of the "Library Manager" dialog.
  3. Type Adafruit Unified Sensor in the "Filter your search..." field.
  4. Press the Enter key.
  5. Scroll down through the list of libraries until you see the "Adafruit Unified Sensor" entry. Click on it.
    A menu and button will appear at the bottom of the entry.
  6. Click the "Install" button in the "Adafruit Unified Sensor" entry.
  7. Wait for the installation to finish.
  8. Click the "Close" button in the "Library Manager" dialog.
    The "Library Manager" dialog will close.

Now try compiling or uploading your sketch again. Hopefully this time you won't have any errors and everything will work as expected.

3

Thank you very much. You solved my problem.
R

4

You are welcome. I'm glad it is working now.

Regards,
Per

5

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