Configuration¶

All settings are stored in NVS (Non-Volatile Storage) and survive firmware and filesystem updates. Configure via the web UI Settings page or the REST API.

Full Configuration Reference¶

{
  "deviceName": "SQM-ESP32",
  "timezone": "UTC",
  "primaryTimeSource": 0,
  "secondaryTimeSource": 1,

  "wifi": {
    "ssid": "YourWiFiSSID",
    "password": "YourWiFiPassword",
    "hostname": "sqm-esp32",
    "autoReconnect": true,
    "reconnectDelayMs": 1000,
    "maxReconnectDelayMs": 300000
  },

  "ntp": {
    "enabled": true,
    "server1": "pool.ntp.org",
    "server2": "time.nist.gov",
    "timezone": "UTC0",
    "gmtOffsetSec": 0,
    "daylightOffsetSec": 0,
    "syncIntervalMs": 600000
  },

  "gps": {
    "enabled": false,
    "rxPin": 17,
    "txPin": 16,
    "baudRate": 9600
  },

  "mqtt": {
    "enabled": false,
    "broker": "mqtt.example.com",
    "port": 1883,
    "username": "",
    "password": "",
    "topic": "sqm/data",
    "publishIntervalMs": 60000
  },

  "ota": {
    "enabled": false,
    "password": ""
  },

  "rain": {
    "enabled": false,
    "rxPin": 18,
    "txPin": 19,
    "baudRate": 9600,
    "mode": "polling",
    "resolution": "high",
    "units": "metric"
  },

  "sensor": {
    "readIntervalMs": 5000,
    "i2cSDA": 21,
    "i2cSCL": 22,
    "i2cFrequency": 100000
  }
}

Fields¶

Device¶

Field	Type	Default	Description
`deviceName`	string	`"SQM-ESP32"`	Friendly name shown in the web UI
`timezone`	string	`"UTC"`	Display timezone
`primaryTimeSource`	int	`0`	Primary time source: `0` = NTP, `1` = GPS
`secondaryTimeSource`	int	`1`	Fallback time source: `0` = NTP, `1` = GPS

WiFi¶

Field	Type	Default	Description
`ssid`	string	—	Network name (2.4 GHz only)
`password`	string	—	Network password
`hostname`	string	`"sqm-esp32"`	mDNS hostname (`hostname.local`)
`autoReconnect`	bool	`true`	Reconnect on WiFi drop
`reconnectDelayMs`	int	`1000`	Initial reconnect delay (ms)
`maxReconnectDelayMs`	int	`300000`	Max reconnect backoff — 5 min

NTP¶

Field	Type	Default	Description
`enabled`	bool	`true`	Enable NTP time sync
`server1`	string	`"pool.ntp.org"`	Primary NTP server
`server2`	string	`"time.nist.gov"`	Fallback NTP server
`timezone`	string	`"UTC0"`	POSIX timezone string
`gmtOffsetSec`	int	`0`	UTC offset in seconds (e.g. `-28800` for PST)
`daylightOffsetSec`	int	`0`	DST offset in seconds
`syncIntervalMs`	int	`600000`	Re-sync interval — default 10 minutes

POSIX timezone strings

Examples: GMT0, EST5EDT,M3.2.0,M11.1.0, PST8PDT,M3.2.0,M11.1.0, CET-1CEST,M3.5.0,M10.5.0/3. A full list is available at timezonedb.com.

GPS¶

Field	Type	Default	Description
`enabled`	bool	`false`	Enable GPS module
`rxPin`	int	`17`	ESP32 RX pin (connects to GPS TX)
`txPin`	int	`16`	ESP32 TX pin (connects to GPS RX)
`baudRate`	int	`9600`	GPS module baud rate (typically 9600)

When GPS is enabled and has a fix, it can serve as the primary time source for accurate timestamps independent of network connectivity.

MQTT¶

Field	Type	Default	Description
`enabled`	bool	`false`	Enable MQTT publishing
`broker`	string	—	Broker hostname or IP
`port`	int	`1883`	Broker port
`username`	string	`""`	Auth username (leave empty if none)
`password`	string	`""`	Auth password
`topic`	string	`"sqm/data"`	Publish topic
`publishIntervalMs`	int	`60000`	Publish interval — default 1 min

ArduinoOTA¶

Field	Type	Default	Description
`enabled`	bool	`false`	Enable command-line ArduinoOTA uploads
`password`	string	`""`	Required when command-line ArduinoOTA is enabled

ArduinoOTA is disabled unless both ota.enabled is true and ota.password is set. The web UI OTA upload page is separate from command-line ArduinoOTA.

Rain Sensor¶

Field	Type	Default	Description
`enabled`	bool	`false`	Enable Hydreon RG-15 rain sensor
`rxPin`	int	`18`	ESP32 RX pin (connects to RG-15 TX)
`txPin`	int	`19`	ESP32 TX pin (connects to RG-15 RX)
`baudRate`	int	`9600`	RG-15 serial baud rate
`mode`	string	`"polling"`	`"polling"` or `"continuous"`
`resolution`	string	`"high"`	`"high"`, `"low"`, or `"switch"`
`units`	string	`"metric"`	`"metric"`, `"imperial"`, or `"switch"`

Sensor¶

Field	Type	Default	Description
`readIntervalMs`	int	`5000`	How often sensors are polled (ms)
`i2cSDA`	int	`21`	SDA GPIO pin
`i2cSCL`	int	`22`	SCL GPIO pin
`i2cFrequency`	int	`100000`	I2C clock speed (Hz)

Security Notes¶

SQMeter currently assumes a trusted LAN:

The web UI, REST API, WebSocket streams, and OTA endpoints do not require HTTP authentication.
GET /api/config redacts stored WiFi, MQTT, and ArduinoOTA password fields, but still exposes non-secret operational settings.
HTTP traffic is plaintext, so credentials sent through setup or config updates are visible to devices that can observe the LAN.
Command-line ArduinoOTA is disabled unless ota.enabled is true and ota.password is set.

Keep the device on a private network or isolated observatory VLAN. Do not expose port 80, port 2020, or ArduinoOTA to the public internet.

Some settings are applied immediately, but hardware bus settings such as I2C pins, GPS pins, and RG-15 pins may require a restart because the sensors are initialised during firmware startup.

Updating via API¶

# Read current config
curl http://sqmeter.local/api/config

# Partial update — only the fields you include are changed
curl -X POST http://sqmeter.local/api/config \
  -H "Content-Type: application/json" \
  -d '{"deviceName": "backyard-sqm", "ntp": {"server1": "time.google.com"}}'

Password fields returned by GET /api/config are masked as ********. Sending a masked or empty password back to POST /api/config preserves the stored value; send null for a password field only when you intentionally want to clear it.

Backup & Restore¶

# Backup
curl http://sqmeter.local/api/config > config-backup.json

# Restore
curl -X POST http://sqmeter.local/api/config \
  -H "Content-Type: application/json" \
  -d @config-backup.json