http://www.arrl.org/files/file/QST/This%20Month%20in%20QST/August2019/AUGUST%20ToC.pdf pcb-rnd, reveng https://diyodemag.com/features/arduino_nano_uno_air_quality_monitor_datalogger air montior v1 https://diyodemag.com/projects/air_quality_monitor_v2_an_arduino_nano-based_air_quality_monitor_datalogger_and_clock air montior v2 https://rsgb.org/main/blog/publications/radcom/2023/01/19/radcom-february-2023-vol-99-no-2/ text references and screenshot lightning detector: https://github.com/erichVK5/erichVK5-lightning-detector