Issues with Grove Alcohol Sensor

Hi, im having issues with the grove alcohol sensor. According the instructions I am supposed to read the RS_air value first through serial. I was never able to connect it because uploading the sketch continuously gave errors. Today I tried again and it worked but the serial monitor gave an unreadable output. Then tried to upload again and I was back to the same failure message below. Any idea why this is happening. Also what does it mean that the sensor needs to be preheated for 48 hours? Do I need to leave it connected and powered to the arduino/grove before it will work? What will happen if I disconnect it? Do i need another 48 hours to use it?


  • Already tried deleting com ports, restarting IDE, changing com ports reinstalling drivers… All no help.







    Arduino: 1.8.7 (Windows 10), Board: “Arduino/Genuino Uno”



    C:\Program Files (x86)\Arduino\arduino-builder -dump-prefs -logger=machine -hardware C:\Program Files (x86)\Arduino\hardware -tools C:\Program Files (x86)\Arduino\tools-builder -tools C:\Program Files (x86)\Arduino\hardware\tools\avr -built-in-libraries C:\Program Files (x86)\Arduino\libraries -libraries C:\Users\John\Desktop\Sketchbook_Starter_Kit_V2.0-master\Sketchbook_Starter_Kit_V2.0-master\libraries -fqbn=arduino:avr:uno -vid-pid=0X2341_0X0043 -ide-version=10807 -build-path C:\Users\John\AppData\Local\Temp\arduino_build_560922 -warnings=none -build-cache C:\Users\John\AppData\Local\Temp\arduino_cache_148407 -prefs=build.warn_data_percentage=75 -prefs=runtime.tools.arduinoOTA.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.arduinoOTA-1.2.1.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avrdude.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avrdude-6.3.0-arduino14.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avr-gcc.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avr-gcc-5.4.0-atmel3.6.1-arduino2.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -verbose C:\Users\John\Desktop\Sketchbook_Starter_Kit_V2.0-master\Sketchbook_Starter_Kit_V2.0-master\sketch_nov03a\sketch_nov03a.ino

    C:\Program Files (x86)\Arduino\arduino-builder -compile -logger=machine -hardware C:\Program Files (x86)\Arduino\hardware -tools C:\Program Files (x86)\Arduino\tools-builder -tools C:\Program Files (x86)\Arduino\hardware\tools\avr -built-in-libraries C:\Program Files (x86)\Arduino\libraries -libraries C:\Users\John\Desktop\Sketchbook_Starter_Kit_V2.0-master\Sketchbook_Starter_Kit_V2.0-master\libraries -fqbn=arduino:avr:uno -vid-pid=0X2341_0X0043 -ide-version=10807 -build-path C:\Users\John\AppData\Local\Temp\arduino_build_560922 -warnings=none -build-cache C:\Users\John\AppData\Local\Temp\arduino_cache_148407 -prefs=build.warn_data_percentage=75 -prefs=runtime.tools.arduinoOTA.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.arduinoOTA-1.2.1.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avrdude.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avrdude-6.3.0-arduino14.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avr-gcc.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -prefs=runtime.tools.avr-gcc-5.4.0-atmel3.6.1-arduino2.path=C:\Program Files (x86)\Arduino\hardware\tools\avr -verbose C:\Users\John\Desktop\Sketchbook_Starter_Kit_V2.0-master\Sketchbook_Starter_Kit_V2.0-master\sketch_nov03a\sketch_nov03a.ino

    Using board ‘uno’ from platform in folder: C:\Program Files (x86)\Arduino\hardware\arduino\avr

    Using core ‘arduino’ from platform in folder: C:\Program Files (x86)\Arduino\hardware\arduino\avr

    Detecting libraries used…

    “C:\Program Files (x86)\Arduino\hardware\tools\avr/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=10807 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR “-IC:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino” “-IC:\Program Files (x86)\Arduino\hardware\arduino\avr\variants\standard” “C:\Users\John\AppData\Local\Temp\arduino_build_560922\sketch\sketch_nov03a.ino.cpp” -o nul

    Generating function prototypes…

    “C:\Program Files (x86)\Arduino\hardware\tools\avr/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=10807 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR “-IC:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino” “-IC:\Program Files (x86)\Arduino\hardware\arduino\avr\variants\standard” “C:\Users\John\AppData\Local\Temp\arduino_build_560922\sketch\sketch_nov03a.ino.cpp” -o “C:\Users\John\AppData\Local\Temp\arduino_build_560922\preproc\ctags_target_for_gcc_minus_e.cpp”

    “C:\Program Files (x86)\Arduino\tools-builder\ctags\5.8-arduino11/ctags” -u --language-force=c++ -f - --c+±kinds=svpf --fields=KSTtzns --line-directives “C:\Users\John\AppData\Local\Temp\arduino_build_560922\preproc\ctags_target_for_gcc_minus_e.cpp”

    Compiling sketch…

    “C:\Program Files (x86)\Arduino\hardware\tools\avr/bin/avr-g++” -c -g -Os -w -std=gnu++11 -fpermissive -fno-exceptions -ffunction-sections -fdata-sections -fno-threadsafe-statics -Wno-error=narrowing -MMD -flto -mmcu=atmega328p -DF_CPU=16000000L -DARDUINO=10807 -DARDUINO_AVR_UNO -DARDUINO_ARCH_AVR “-IC:\Program Files (x86)\Arduino\hardware\arduino\avr\cores\arduino” “-IC:\Program Files (x86)\Arduino\hardware\arduino\avr\variants\standard” “C:\Users\John\AppData\Local\Temp\arduino_build_560922\sketch\sketch_nov03a.ino.cpp” -o “C:\Users\John\AppData\Local\Temp\arduino_build_560922\sketch\sketch_nov03a.ino.cpp.o”

    Compiling libraries…

    Compiling core…

    Using precompiled core: C:\Users\John\AppData\Local\Temp\arduino_cache_148407\core\core_arduino_avr_uno_0c812875ac70eb4a9b385d8fb077f54c.a

    Linking everything together…

    “C:\Program Files (x86)\Arduino\hardware\tools\avr/bin/avr-gcc” -w -Os -g -flto -fuse-linker-plugin -Wl,–gc-sections -mmcu=atmega328p -o “C:\Users\John\AppData\Local\Temp\arduino_build_560922/sketch_nov03a.ino.elf” “C:\Users\John\AppData\Local\Temp\arduino_build_560922\sketch\sketch_nov03a.ino.cpp.o” “C:\Users\John\AppData\Local\Temp\arduino_build_560922/…\arduino_cache_148407\core\core_arduino_avr_uno_0c812875ac70eb4a9b385d8fb077f54c.a” “-LC:\Users\John\AppData\Local\Temp\arduino_build_560922” -lm

    “C:\Program Files (x86)\Arduino\hardware\tools\avr/bin/avr-objcopy” -O ihex -j .eeprom --set-section-flags=.eeprom=alloc,load --no-change-warnings --change-section-lma .eeprom=0 “C:\Users\John\AppData\Local\Temp\arduino_build_560922/sketch_nov03a.ino.elf” “C:\Users\John\AppData\Local\Temp\arduino_build_560922/sketch_nov03a.ino.eep”

    “C:\Program Files (x86)\Arduino\hardware\tools\avr/bin/avr-objcopy” -O ihex -R .eeprom “C:\Users\John\AppData\Local\Temp\arduino_build_560922/sketch_nov03a.ino.elf” “C:\Users\John\AppData\Local\Temp\arduino_build_560922/sketch_nov03a.ino.hex”

    “C:\Program Files (x86)\Arduino\hardware\tools\avr/bin/avr-size” -A “C:\Users\John\AppData\Local\Temp\arduino_build_560922/sketch_nov03a.ino.elf”

    Sketch uses 3934 bytes (12%) of program storage space. Maximum is 32256 bytes.

    Global variables use 226 bytes (11%) of dynamic memory, leaving 1822 bytes for local variables. Maximum is 2048 bytes.

    C:\Program Files (x86)\Arduino\hardware\tools\avr/bin/avrdude -CC:\Program Files (x86)\Arduino\hardware\tools\avr/etc/avrdude.conf -v -patmega328p -carduino -PCOM25 -b115200 -D -Uflash:w:C:\Users\John\AppData\Local\Temp\arduino_build_560922/sketch_nov03a.ino.hex:i



    avrdude: Version 6.3-20171130

    Copyright © 2000-2005 Brian Dean, http://www.bdmicro.com/

    Copyright © 2007-2014 Joerg Wunsch



    System wide configuration file is “C:\Program Files (x86)\Arduino\hardware\tools\avr/etc/avrdude.conf”



    Using Port : COM25

    Using Programmer : arduino

    Overriding Baud Rate : 115200

    avrdude: ser_open(): can’t set com-state for “\.\COM25”



    avrdude done. Thank you.



    An error occurred while uploading the sketch

    Error while setting serial port parameters: 9,600 N 8 1

Hi there,


  1. the code uses the pin15(A1) for scl, A0 for data.
  2. please make sure COM port select before downloading the code, if already selected, please double click the reset button on arduino. then reprogram it again.
  3. we base on MQ303A datasheet and suggest preheat time 48 hours to get good reading. If you power off it for a long time, you have to do preheat 48 hours again. thanks.