Integrations

ESPGeiger exposes radiation data through several channels (MQTT, Webhook, JSON endpoint). This page shows how to connect these to common monitoring and automation platforms.

JSON Endpoint

The built-in web server exposes a JSON endpoint at /json:

http://192.168.1.100/json

Response:

{"ut":5025,"c":42.00,"s":0.28,"c5":41.50,"c15":40.90,"cs":0.70,"r":151.0,"tc":9876,"mem":19088,"rssi":-45,"tick":712,"t_max":8012,"lps":59831}

Field	Description
`ut`	Uptime in seconds
`c`	Current CPM
`s`	Current μSv/h
`c5`	5-minute smoothed CPM
`c15`	15-minute smoothed CPM
`cs`	Current CPS
`r`	μSv conversion ratio
`tc`	Total clicks since boot
`mem`	Free heap memory in bytes
`rssi`	WiFi signal strength in dBm
`hv`	HV reading in volts (ESPGeiger-HW only)
`tick`	EMA-smoothed duration of the 1-second tick callback in microseconds (sTickerCB cost). Typical load indicator; α = 1/8 so single-tick spikes (MQTT publish, etc.) are averaged out. Lower is better.
`t_max`	Peak `tick` observed in the current 60-tick window (rolling reset). Use alongside `tick` to see worst-case cost.
`lps`	Loop iterations counted in the last second.

GeigerLog

GeigerLog is a free cross-platform log/plot tool for Geiger counters. ESPGeiger exposes a GeigerLog-compatible endpoint at /lastdata that works with GeigerLog’s built-in WiFiClient device.

Configure GeigerLog

In GeigerLog open Device → WiFiClient → Config WiFiClient Device.
Set the IP address and port to the ESPGeiger device (port 80).
Point the data URL at /lastdata.
Save, then connect the WiFiClient device.

The /lastdata endpoint returns a single comma-separated line matching the GeigerLog WiFiClient format:

22.50, 0.37, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan

The first two values are the current CPM and CPS. The remaining ten fields are reported as nan - GeigerLog ignores them and plots only the two populated variables.

Notes

Polling is driven by GeigerLog - ESPGeiger responds on each request, so cadence is whatever you configure on the GeigerLog side.
The endpoint is always available; there is no toggle in the ESPGeiger portal.
If you need richer data (5-minute or 15-minute CPM, HV, memory, RSSI) consume /json instead from your own tooling.

Prometheus (native `/metrics`)

ESPGeiger exposes a native Prometheus text exposition endpoint at /metrics. No proxy or exporter needed.

Scrape config

# prometheus.yml
scrape_configs:
  - job_name: espgeiger
    metrics_path: /metrics
    scrape_interval: 30s
    static_configs:
      - targets:
          - 192.168.1.100   # your device(s)
          - 192.168.1.101

For automatic discovery, point Prometheus at all _espgeiger._tcp mDNS entries via your service discovery layer.

Sample output

# HELP device_info Device metadata; value always 1. Join via on(chipid) for naming.
# TYPE device_info gauge
device_info{chipid="d5536d",name="Garage",model="ESPGeiger-HW",ver="0.11.0",env="espgeigerhw"} 1

# HELP geiger_cpm Counts per minute (window label selects averaging period)
# TYPE geiger_cpm gauge
geiger_cpm{chipid="d5536d",window="1m"} 31.50
geiger_cpm{chipid="d5536d",window="5m"} 30.20
geiger_cpm{chipid="d5536d",window="15m"} 29.80

# HELP geiger_cps Instantaneous counts per second
geiger_cps{chipid="d5536d"} 0.52

# HELP geiger_usv_per_hour Dose rate in microsieverts per hour
geiger_usv_per_hour{chipid="d5536d"} 0.2086

# HELP geiger_lifetime_clicks_total Total clicks counted over device life
# TYPE geiger_lifetime_clicks_total counter
geiger_lifetime_clicks_total{chipid="d5536d"} 1845231

# HELP device_uptime_seconds Seconds since boot
device_uptime_seconds{chipid="d5536d"} 90523

# HELP device_free_heap_bytes Free heap memory
device_free_heap_bytes{chipid="d5536d"} 19432

# HELP device_wifi_rssi_dbm WiFi signal strength
device_wifi_rssi_dbm{chipid="d5536d"} -54

# HELP geiger_pulse_interval_seconds Inter-pulse intervals in seconds, log2 buckets
# TYPE geiger_pulse_interval_seconds histogram
geiger_pulse_interval_seconds_bucket{chipid="d5536d",le="0.000064"} 0
geiger_pulse_interval_seconds_bucket{chipid="d5536d",le="0.000128"} 0
...
geiger_pulse_interval_seconds_bucket{chipid="d5536d",le="+Inf"} 1845231
geiger_pulse_interval_seconds_count{chipid="d5536d"} 1845231

Label model

Operational metrics carry only chipid (the stable, deterministic device MAC). Friendly name, model and firmware version live in the separate device_info metric. This means:

Renaming a device in the portal does not fork its historical time series.
Dashboard joins use on(chipid) group_left(name) to bring in the friendly name.

PromQL examples

# Current CPM with friendly name as legend
geiger_cpm{window="1m"} * on(chipid) group_left(name) device_info

# Dose rate averaged over 1 hour
avg_over_time(geiger_usv_per_hour[1h])
  * on(chipid) group_left(name) device_info

# Alert when any device exceeds 1 µSv/h sustained for 5 min
- alert: RadiationHigh
  expr: avg_over_time(geiger_usv_per_hour[5m]) > 1
  labels:
    severity: warning
  annotations:
    summary: " dose rate sustained above 1 µSv/h"

# Devices that haven't reported in 5 min
time() - timestamp(geiger_cpm{window="1m"}) > 300

Notes

The endpoint is always available; there is no toggle in the portal.
Histogram bucket boundaries are powers of two starting at 64 µs (inter-pulse interval). The top bucket is +Inf.
geiger_lifetime_clicks_total is a Prometheus counter (monotonically increasing); use rate() for click rate.

Prometheus via Telegraf

If you’d rather pull from the /json endpoint (eg you already run Telegraf, or you want to add fields not in /metrics), Telegraf can poll JSON and expose Prometheus metrics:

# telegraf.conf

[[inputs.http]]
  urls = ["http://192.168.1.100/json"]
  method = "GET"
  timeout = "5s"
  data_format = "json_v2"
  name_override = "espgeiger"
  [[inputs.http.tags]]
    device = "espgeiger-xxxxxx"
  [[inputs.http.json_v2]]
    [[inputs.http.json_v2.field]]
      path = "c"
      rename = "cpm"
      type = "float"
    [[inputs.http.json_v2.field]]
      path = "s"
      rename = "usv_h"
      type = "float"
    [[inputs.http.json_v2.field]]
      path = "c5"
      rename = "cpm5"
      type = "float"
    [[inputs.http.json_v2.field]]
      path = "c15"
      rename = "cpm15"
      type = "float"
    [[inputs.http.json_v2.field]]
      path = "cs"
      rename = "cps"
      type = "float"
    [[inputs.http.json_v2.field]]
      path = "tc"
      rename = "total_clicks"
      type = "int"
    [[inputs.http.json_v2.field]]
      path = "ut"
      rename = "uptime_seconds"
      type = "int"
    [[inputs.http.json_v2.field]]
      path = "mem"
      rename = "free_heap"
      type = "int"
    [[inputs.http.json_v2.field]]
      path = "rssi"
      rename = "wifi_rssi"
      type = "int"

[[outputs.prometheus_client]]
  listen = ":9273"

Prometheus can then scrape http://<telegraf-host>:9273/metrics.

Prometheus via MQTT Exporter

If you are already publishing via MQTT, the mqtt2prometheus exporter converts MQTT topics into Prometheus metrics:

# mqtt2prometheus.yaml
mqtt:
  server: tcp://mqtt-broker:1883
  topic_path: ESPGeiger-+/stat/+
  device_id_regex: "ESPGeiger-(?P<deviceid>[0-9a-f]+)/stat/.+"
  qos: 0
metrics:
  - prom_name: espgeiger_cpm
    mqtt_name: CPM
    help: Current counts per minute
    type: gauge
  - prom_name: espgeiger_usv
    mqtt_name: uSv
    help: Current microsieverts per hour
    type: gauge
  - prom_name: espgeiger_cpm5
    mqtt_name: CPM5
    help: 5-minute smoothed CPM
    type: gauge

InfluxDB via Telegraf

To write directly to InfluxDB instead of Prometheus:

[[inputs.http]]
  urls = ["http://192.168.1.100/json"]
  data_format = "json_v2"
  name_override = "espgeiger"
  # ... field config as above ...

[[outputs.influxdb_v2]]
  urls = ["http://influxdb:8086"]
  token = "YOUR_TOKEN"
  organization = "your-org"
  bucket = "radiation"

Node-RED

Node-RED can poll the JSON endpoint and route data anywhere:

[
  {
    "id": "poll",
    "type": "inject",
    "repeat": "60",
    "topic": "",
    "payload": "",
    "payloadType": "date"
  },
  {
    "id": "http",
    "type": "http request",
    "method": "GET",
    "url": "http://192.168.1.100/json",
    "ret": "obj"
  }
]

Wire poll → http → your destination (MQTT, database, dashboard, webhook, etc.).

Home Assistant

If using MQTT with Home Assistant autodiscovery enabled, ESPGeiger sensors appear automatically. See Home Assistant for details.

For REST polling without MQTT:

# configuration.yaml
rest:
  - resource: http://192.168.1.100/json
    scan_interval: 30
    sensor:
      - name: "Radiation CPM"
        value_template: ""
        unit_of_measurement: "CPM"
      - name: "Radiation uSv/h"
        value_template: ""
        unit_of_measurement: "μSv/h"
        device_class: "radiation"
      - name: "ESPGeiger WiFi RSSI"
        value_template: ""
        unit_of_measurement: "dBm"
        device_class: "signal_strength"
      - name: "ESPGeiger Free Heap"
        value_template: ""
        unit_of_measurement: "B"

Grafana Dashboard

Once data is in Prometheus or InfluxDB, Grafana can visualise it. A simple dashboard query for Prometheus:

# Current CPM
espgeiger_cpm

# 5 minute average
avg_over_time(espgeiger_cpm[5m])

# Alert when above threshold
espgeiger_cpm > 100

Integrations

JSON Endpoint

GeigerLog

Configure GeigerLog

Notes

Prometheus (native /metrics)

Scrape config

Sample output

Label model

PromQL examples

Notes

Prometheus via Telegraf

Prometheus via MQTT Exporter

InfluxDB via Telegraf

Node-RED

Home Assistant

Grafana Dashboard

Prometheus (native `/metrics`)