Few days later I will make a pull request or Replica of Your Code, due to changes about specificy with showing CPM (I think it is needed to be shown), and Your Code is more for SBM-20 than for J305/M4011.
Коэффициент Conversion Factor для перевода CPM в мкЗв/ч (uSv/h) (для счётчика СБМ20 — коэффциент равен 0.0057, а для счётчиков J305/M4011, по информации из сети — 0.0081)
in Your Code You are using COEF 0.0057, but the Code in Requested Source is more valuable for J305/M4011. Also I can't calibrate the Geiger DIY. But after some fixes in my code I've only getting more trusted data of Geiger Radioactivity. It is sent to my server via WIFI module ESP8266 (https://budka.org/smartHouse/web/stats).
Here is my Code which is communicating (for now) only with WIFI.
eugeniykh
commented
2 years ago 
But...
Few days later I will make a pull request or Replica of Your Code, due to changes about specificy with showing CPM (I think it is needed to be shown), and Your Code is more for SBM-20 than for J305/M4011.
I've analyzed these sources https://mysku.ru/blog/china-stores/78189.html (sorry its in Russian).
Коэффициент Conversion Factor для перевода CPM в мкЗв/ч (uSv/h) (для счётчика СБМ20 — коэффциент равен 0.0057, а для счётчиков J305/M4011, по информации из сети — 0.0081)in Your Code You are using COEF 0.0057, but the Code in Requested Source is more valuable for J305/M4011. Also I can't calibrate the Geiger DIY. But after some fixes in my code I've only getting more trusted data of Geiger Radioactivity. It is sent to my server via WIFI module ESP8266 (https://budka.org/smartHouse/web/stats).
Here is my Code which is communicating (for now) only with WIFI.
https://pastecode.io/s/dp4mw8s4
Also I will modificate Your Code with some these Changes. Or if You can change it by Yourself - it will be The Best.
Thanks You for Your Manual. It is Awesome, Dude!