> ## Documentation Index
> Fetch the complete documentation index at: https://docs.agrihub360.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Metrics

> The shared catalogue that says what a reading measures and in which unit.

Every reading names its metric with an integer `metric_id`. The catalogue is shared across all devices, so a soil moisture reading from any device is id `220` in percent. The API stores the value as sent and does not convert units, so the device converts to the catalogue unit before posting.

## Catalogue

| ID    | Metric        | Unit  | Notes                                               |
| ----- | ------------- | ----- | --------------------------------------------------- |
| `2`   | Voltage       | V     | Battery voltage where the device reports volts      |
| `30`  | Capacity      | mAh   |                                                     |
| `70`  | Temperature   | °C    | Soil or air, by device channel                      |
| `90`  | Wind speed    | m/s   |                                                     |
| `110` | Humidity      | %     |                                                     |
| `120` | pH            | pH    |                                                     |
| `140` | Luminosity    | lux   |                                                     |
| `160` | Direction     | °     | Wind direction, degrees from north                  |
| `200` | Battery       | %     | Battery level where the device reports a percentage |
| `201` | Signal        | %     | Radio signal strength as reported by the device     |
| `220` | Soil moisture | %     | Volumetric water content                            |
| `224` | Conductivity  | mS/cm |                                                     |

Battery has two ids on purpose. Post `200` when the device reports a percentage and `2` when it reports volts. Never scale one into the other with a guessed curve.

<Warning>
  Ids `221` to `223` (nitrogen, phosphorus and potassium) exist in the catalogue but aren't a supported reading. Don't build on them.
</Warning>

## Adding a Metric

Need a metric that isn't listed? Ask for it through [support](https://www.agrihub360.com/support). Don't reuse an existing id for a different measurement: the models read the id, not the device, and a mislabelled reading reaches them.