# Data format 4 (URL)

Related Ruuvi Devices: RuuviTag, up to B3 hardware (superceded in 2018)

The data is packed in [Eddystone URL](https://developers.google.com/beacons/eddystone) with a base of [https://ruu.vi/#](https://ruu.vi) and 9 [URL-safe base64](https://en.wikipedia.org/wiki/Base64#URL_applications) characters. Example URL is <https://ruu.vi/#BFwaAMjlQ>. This is decoded to `0x045c1a00c8e5`

| Offset |     Allowed values     | Description                                                                                                                     |
| ------ | :--------------------: | ------------------------------------------------------------------------------------------------------------------------------- |
| 0      |            4           | Data format definition (4 = current sensor readings)                                                                            |
| 1      |       `0 ... 200`      | Humidity (one lsb is 0.5%, e.g. 128 is 64%)                                                                                     |
| 2      | `-127 ... 127, signed` | Temperature (MSB is sign, next 7 bits are decimal value)                                                                        |
| 3      |        `0 ... 0`       | Temperature (fraction, 1/100.). Not used, reads always as 0.                                                                    |
| 4 - 5  |      `0 ... 65535`     | Pressure (Most Significant Byte first, value - 50kPa). Rounded to 1 hPa accuracy.                                               |
| 6      |        `0..255`        | Random id of tag, only present in format 4. NOTE! because of the URL limitation, only 6 most significant bits will be readable. |

## Data field descriptions

## Temperature

Values supported: -127.99 °C to +127.99 °C in 0.01 °C increments.

*Example*

| Value    | Measurement |
| -------- | ----------- |
| `0x0000` | 0 °C        |
| `0x8145` | -1.69 °C    |
| `0x0145` | +1.69 °C    |

## Humidity

Values supported: 0.0 % to 100 % in 0.5 % increments.

*Example*

| Value | Measurement |
| ----- | ----------- |
| `000` | 0%          |
| `128` | 64.0%       |
| `200` | 100.0%      |

## Atmospheric Pressure

Values supported: 50000 Pa to 115536 Pa in 1 Pa increments.

*Example*

| Value   | Measurement                            |
| ------- | -------------------------------------- |
| `00000` | 50000 Pa                               |
| `51325` | 101325 Pa (average sea-level pressure) |
| `65536` | 115536 Pa                              |

## Tag ID (only on format 4)

Contains a single random base 64 character used to identify tag.


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.ruuvi.com/communication/bluetooth-advertisements/data-format-4-url.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.