Data Parsing

This page documents the binary data formats used by Aranet sensors for current readings, historical data, and advertisements.

Aranet4 Current Readings

Characteristic: f0cd3001-95da-4f4b-9ac8-aa55d312af0c
Total Length: 13 bytes

Offset	Bytes	Name	Type	Transform
0-1	SS:SS	CO₂ (ppm)	u16LE	none
2-3	TT:TT	Temperature	u16LE	÷ 20.0 → °C
4-5	UU:UU	Pressure	u16LE	÷ 10 → hPa
6	VV	Humidity (%)	u8	none
7	WW	Battery (%)	u8	none
8	XX	Status	u8	See color enum
9-10	YY:YY	Interval (s)	u16LE	none
11-12	ZZ:ZZ	Age (s)	u16LE	none

Rust Parsing Example

use byteorder::{LittleEndian, ReadBytesExt};
use std::io::Cursor;

fn parse_aranet4_reading(data: &[u8]) -> Result<CurrentReading, Error> {
    let mut cursor = Cursor::new(data);

    Ok(CurrentReading {
        co2: cursor.read_u16::<LittleEndian>()?,
        temperature: cursor.read_u16::<LittleEndian>()? as f32 / 20.0,
        pressure: cursor.read_u16::<LittleEndian>()? as f32 / 10.0,
        humidity: cursor.read_u8()?,
        battery: cursor.read_u8()?,
        status: Status::try_from(cursor.read_u8()?)?,
        interval: cursor.read_u16::<LittleEndian>()?,
        age: cursor.read_u16::<LittleEndian>()?,
    })
}

Aranet2 Current Readings

Characteristic: f0cd1504-95da-4f4b-9ac8-aa55d312af0c

Offset	Name	Type	Transform
0-1	Unknown	u16LE	—
2-3	Interval (s)	u16LE	none
4-5	Age (s)	u16LE	none
6	Battery (%)	u8	none
7-8	Temperature	u16LE	÷ 20.0 → °C
9-10	Humidity	u16LE	÷ 10.0 → %
11	Status Flags	u8	bits[0:1]=humidity, bits[2:3]=temp

AranetRn+ (Radon) Readings

Characteristic: f0cd3001-95da-4f4b-9ac8-aa55d312af0c Minimum Length: 18 bytes (extended format with averages is 42 bytes)

Offset	Name	Type	Transform
0-1	Device Type	u16LE	0x0003 = Radon
2-3	Interval (s)	u16LE	none
4-5	Age (s)	u16LE	none
6	Battery (%)	u8	none
7-8	Temperature	u16LE	÷ 20.0 → °C
9-10	Pressure	u16LE	÷ 10 → hPa
11-12	Humidity	u16LE	÷ 10.0 → %
13-16	Radon (Bq/m³)	u32LE	none
17	Status	u8	color enum
18-21	24h Avg Time	u32LE	seconds since epoch
22-25	24h Avg Value	u32LE	Bq/m³ (≥0xff000000 = in progress)
26-29	7d Avg Time	u32LE	seconds since epoch
30-33	7d Avg Value	u32LE	Bq/m³ (≥0xff000000 = in progress)
34-37	30d Avg Time	u32LE	seconds since epoch
38-41	30d Avg Value	u32LE	Bq/m³ (≥0xff000000 = in progress)

Note

If an average value is ≥ 0xff000000, it indicates the average is still being calculated and is not yet available.

Aranet Radiation Readings

Offset	Name	Type	Transform
0-1	Unknown	u16LE	—
2-3	Interval (s)	u16LE	none
4-5	Age (s)	u16LE	none
6	Battery (%)	u8	none
7-10	Dose Rate	u32LE	÷ 1000 → µSv/h
11-18	Dose Total	u64LE	÷ 1,000,000 → mSv
19-26	Duration (s)	u64LE	none
27	Status	u8	—

History Parameters

When downloading historical data, each parameter type must be requested separately:

Value	Name	Data Size	Notes
1	TEMPERATURE	u16	Raw ÷ 20 = °C
2	HUMIDITY	u16	Percentage (0-100)
3	PRESSURE	u16	Raw ÷ 10 = hPa
4	CO2	u16	ppm
5	HUMIDITY2	u16	Tenths of % (AranetRn+)
6	PULSES	u16	Radiation pulses
7	RADIATION_DOSE	u32	Total dose (nSv)
8	RADIATION_DOSE_RATE	u32	Dose rate (nSv/h)
9	RADIATION_DOSE_INTEGRAL	u64	Integral dose
10	RADON_CONCENTRATION	u32	Bq/m³ (4 bytes)

Note

Parameters 1-6 use 2-byte values. Parameters 7-10 use 4-byte values (u32).

Command Bytes

Set Interval (0x90)

Bytes: 90:XX
XX = Interval in minutes (01, 02, 05, 0A)

Set Bluetooth Range (0x92)

Bytes: 92:XX
XX = 00 (standard) or 01 (extended)

Request History V2 (0x61)

Bytes: 61:PP:SS:SS
PP = Parameter (see table above)
SS:SS = Start index (u16LE)

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Made with ❤️ by Cameron Rye