Esphome Radsens Component

August 25, 2025 · View on GitHub

About this repo

This is a full esphome native component for the ClimateGuard Radsens. This was motivated by the coming "custom component-pocolypse" and I still suffer from occasional hangs in the original module (the esp remains pingable but nothing else responds). External components are quite a bit better integrated with esphome and easier for users to use and allow other i2c devices on the same esp32. Esphome actually calls out Wire as a library which doesn't play well with others.

What is a Radsens?

Radsens is a geiger counter built by ClimateGuard. Their pages can be found here. I ordered mine before the war with Ukraine and I don't entirely understand the relation between countries but its worth noting it appears to be a Kazakhstan company.

tindie carries the RadSens

I2C Errors

If you are using this and get i2c errors please let me know with a github issue. It appears to have a timing issue. Setting the switches on startup began failing in esphome 2025.8.0. I re-sorted the switch setup which seems like a bit of a hack, but it at least works for me at the moment.

Setup

Simple Example

external_components:
  - source: github://krbaker/esphome-radsens@v1.0.1
    components: [ radsens ]
    refresh: 600s

i2c:
  - id: bus_a
    frequency: 100kHz

radsens:

sensor:
  - platform: radsens
    dynamic_intensity:
      name: "Dynamic Intensity"
    static_intensity:
      name: "Static Intensity"
    counts_per_minute:
      name: "Counts Per Minute"

Full Configuration

A full configuration can be found here but I recommend reading the following to undestand it.

field	notes
external_components	This is not yet in the core esphome so you need to pull it in this way
external_components:source	This should be pointed to this github repo github://krbaker/esphome-radsens likely you want to take the current release found here using @<tag>
external_components:source:components	There is one and only component here [ radsens ]
external_components:source:refresh	Probably don't need any more than 600s here
radsens	The radens component must be enabled to install the component
radsens:sensativity	This field is not required. If it us unset or set to 0 the component will not set anything. The default according to the docs is 105 and that is what mine was shipped with. You probably do not need this
sensor:radsens	Needed to enable the sensors
sensor:radsens:dynamic_intensity	The 'dynamic_intensity' sensor which is an average intensity over a varying time window
sensor:radsens:static_intensity	The 'static_intensity' sensor which is an average intensity over the last 5min
sensor:radsens:counts_per_mintute	The number of detected impulses since the last update, scaled to a minute window
switch:radsens	Needed to enable the switches
switch:radsens:control_led	Controls if the blue led which flashes when an impulse is detected (default on)
switch:radsens:control_high_voltage	Controls if the high voltage generator is on. When turning off it takes a while to change readings (~5min for me) but it will go to zero (default on)
switch:radsens:control_low_power	Sets a low power mode which turns off the tube power from time to time (default off)

Notes

I did see a failure to communicate with the device when setting the high voltage switch at startup but can't repro. If you see this file a bug.
The endienness is different for some different i2c values, I think I got all of these right but dont be confused by that in code. This was a little surprising at first but I found it matched the arduino code.
Reading the dynamic and static intensity also reset the CPM counter. Given I read them in the update loop I just read all three sequentialy with CPM first. The library for arduino keeps a CPM counter and reads the CPM value before reading anything that seems to reset the CPM value. There is a little bit of time that is probably lost but that is probably still true in the arduino code.
This is my first external component, sensors & switches in the same component took some time but I think are correct. if you see something wrong file an issue or a PR.
The switch restoration I have the least confidence in but it is working in my testing.
It might make sense to convert the exposure numbers from rostom to millisevert
The english documents are not complete. I used a translated Russian docs (4v0 ,1v3) and the arduino library as sources.