Skip to content
BranchesTags

Repository files navigation

ESP_flowiq2200

A collection of Arduino sketches to read Kamstrup FlowIQ 2200 data via CC1101.
Ranging from basic frame reception to ISR-stable MQTT integration.

Intro logo

Features

  • Big Sketch (Full + Compact Frames):

    • flowIQ2200_Full.ino
    • Receives both 0x79 (Compact Frame) and 0x78 (Full Frame).
    • A telegram is transmitted every 16 seconds. First, 7 compact are sent, followed by 1 full.
    • This adds complexity due to handling Full Frames and mechanisms like GDO2 threshold burst detection.

  • Small Sketch (only Compact Frames):

    • flowIQ2200_Compact.ino
    • Receives only 0x79 (Compact Frame).
    • This is the basic approach, as it is significantly simpler in structure, but still uses polling.
    • Simple, but can be blocked by other tasks (like WiFi).
    • The Compact Frame contains all relevant data and is transmitted every 16 seconds.

  • ISR Version (only Compact Frames):

    • ⚠️Recommended⚠️
    • flowIQ2200_Compact_ISR.ino
    • Receives only 0x79 (Compact Frame)
    • Uses ISR to ensure maximum stability while multitasking with services such as WiFi/MQTT.
    • The Compact Frame contains all relevant data and is transmitted every 16 seconds.

  • MQTT Version (The "All-rounder"):

    • ⚠️Also Recommended⚠️
    • flowIQ2200_MQTT.ino
    • The all-in-one solution for seamless integration.
    • Receives only 0x79 (Compact Frame)
    • Features high stability via ISR-based reception.
    • The Compact Frame contains all relevant data and is transmitted every 16 seconds.
    • WiFi: Includes BSSID scanning and robust auto-reconnect logic.
    • MQTT: Automated publishing via PubSubClient with built-in auto-reconnect.

  • Data included in telegrams:

    • Total Consumption (Total Volume): Current overall consumption in m³
    • Month-Start Consumption (Target Volume): Consumption at the beginning of the current month in m³
    • Current Flow: Instantaneous flow rate in L/h
    • Maximum Flow: Maximum flow within the interval in L/h
    • Temperatures (Min/Max): Minimum and maximum temperatures in °C
    • Status: Status information of the meter
    • Date (Target Date): Date of the month start (e.g., 2026-04-01)

  • Promiscuous Mode:
    Allows passive listening to all M-Bus messages in range to identify the meter ID.

  • Multi-step check:

    • ID Check: Filters for your specific Meter-ID.
    • AES Decryption: Uses your individual 16-byte key to unlock the payload.
    • CRC Verification (EN 13757): The code calculates a 16-bit checksum over the decrypted data and compares it with the transmitted CRC bytes.

  • RSSI monitoring

Design Decision

The Compact Frame (CI=0x79) implementation was the main goal and took most of the effort.
The Full Frame (CI=0x78) was added afterwards purely for comparison and validation — and frankly, it was a pain to get working reliably with the CC1101. FIFO limits, burst handling (GDO2), timing… all that complexity for basically no real benefit.

Some sources (e.g., https://github.com/erikxson/watermeter-flowiq2200) claim that Compact and Full Frames contain different data sets — especially for flow values (1-byte vs. 2-byte). That claim was the reason to dig deeper.

After analyzing both frame types from this specific meter, the result is simple:
all relevant data (Total Volume, Target Volume, Flow, Temperature, Status, etc.) is already present in the Compact Frame.

The Full Frame doesn’t add anything useful here. It just confirms that the Compact Frame is complete.

Conclusion:
Handling Full Frames is unnecessary overhead for this device.
Compact Frames (CI=0x79) are simpler, more robust, and get the job done.

Getting started

  • Required Hardware

    • ESP32 DevBoard:
    • CC1101 RF Module: Ensure you use the 868 MHz version (wM-Bus operates at 868.95 MHz).

  • Libraries

    • Crypto (by Rhys Weatherley):

      • Provides AES.h and CBC.h for decryption.

    • CC1101_ESP_Arduino (by wischbgr):

      • The specialized driver for using CC1101 with ESP32 SPI.

  • Wiring Diagram

The CC1101 communicates with the ESP32 via the SPI bus. Since both devices operate at 3.3V, no level shifters are needed.

CC1101 Pin ESP32 Pin (Standard) Description
VCC 3V3 Power Supply (3.3V)
GND GND Ground
SI (MOSI) GPIO 23 Master Out Slave In
SO (MISO) GPIO 19 Master In Slave Out
SCK GPIO 18 Serial Clock
CSN (SS) GPIO 5 Chip Select
GDO0 GPIO 27 RX Interrupt (Data Ready)
GDO2 GPIO 26 FIFO Threshold (For long packets)

Intro logo

  • Configuration in Sketch

    • Before uploading, update these variables in your .ino file:
      • meterId: The ID found on your meter's housing (entered in Hex).
      • key: The 32-character Hex key provided by your water utility company.

  • Serial Log

====== Packet #398  RSSI=-86 dBm ======
[RAW] Len=52  Link-CI=0x8D
[RAW] 44 37 2C 38 19 65 53 3C 16 8D 20 75 33 9A BC ... (Encrypted data)
[ID] Meter-ID OK
[DEC] Application-CI=0x79  plainLen=34
[DEC] D6 F0 79 05 09 B1 79 00 00 00 00 E6 E4 00 ... (Decrypted plain text)

[CRC] read=0xF0D6  calc=0xF0D6  OK
[CI]  Compact Frame (0x79) - FlowIQ 2200

[VAL] total_m3     = 62.755 m3
[VAL] target_m3    = 58.598 m3
[VAL] target_date  = 2026-04-01
[VAL] flow_now     = 0 L/h
[VAL] status       = 0x00000000  OK

Application-CI=0x79 (34 Bytes Plain) - Compact Frame

Original Raw Payload: 44 37 2C 38 19 65 53 3C 16 8D 20 2F F0 36 BC 20 E4 82 60 05 CC 49 F6 D4 4E 27 2A B1 1C 2E 29 D6 99 B4 4C 43 C3 78 BC 78 CC ED F6 A1 3A 09 0F 6B 78 FB 27 04

Decrypted Plain Payload: 35 2A 79 05 09 61 78 00 00 00 00 E6 E4 00 00 5C 02 05 50 00 05 50 00 41 34 0B 0D EB 01 DD F3 00 00 0D

Click here to expand the byte-by-byte table
Byte Index Value (Hex) Interpretation
0 35 Part of CRC Header (Byte 0 of 2)
1 2A Part of CRC Header (Byte 1 of 2)
2 79 Application CI (0x79)
3 05 Part of Kamstrup Header (Byte 0 of 4)
4 09 Part of Kamstrup Header (Byte 1 of 4)
5 61 Part of Kamstrup Header (Byte 2 of 4)
6 78 Part of Kamstrup Header (Byte 3 of 4)
7 00 Part of Status Value (LSB, 00 00 00 00)
8 00 Part of Status Value (Byte 1, 00 00 00 00)
9 00 Part of Status Value (Byte 2, 00 00 00 00)
10 00 Part of Status Value (MSB, 00 00 00 00) -> 0x00000000 OK
11 E6 Part of Target Volume (LSB, E6 E4 00 00)
12 E4 Part of Target Volume (Byte 1, E6 E4 00 00)
13 00 Part of Target Volume (Byte 2, E6 E4 00 00)
14 00 Part of Target Volume (MSB, E6 E4 00 00) -> 58.598 m³
15 5C Part of Max Flow (LSB, 5C 02)
16 02 Part of Max Flow (MSB, 5C 02) -> 604 L/h
17 05 Part of Manufacturer Data (Byte 0 of 6)
18 50 Part of Manufacturer Data (Byte 1 of 6)
19 00 Part of Manufacturer Data (Byte 2 of 6)
20 05 Part of Manufacturer Data (Byte 3 of 6)
21 50 Part of Manufacturer Data (Byte 4 of 6)
22 00 Part of Manufacturer Data (Byte 5 of 6)
23 41 Part of Target Date (Byte 0 of 2)
24 34 Part of Target Date (Byte 1 of 2) -> 2026-04-01
25 0B Min Temperature -> 11 °C
26 0D Max Temperature -> 13 °C
27 EB Part of Current Flow (LSB, EB 01)
28 01 Part of Current Flow (MSB, EB 01) -> 491 L/h
29 DD Part of Total Volume (LSB, DD F3 00 00)
30 F3 Part of Total Volume (Byte 1, DD F3 00 00)
31 00 Part of Total Volume (Byte 2, DD F3 00 00)
32 00 Part of Total Volume (MSB, DD F3 00 00) -> 62.429 m³
33 0D End Value / Extra -> 13

Application-CI=0x78 (55 Bytes Plain) - Full Frame

Original Raw Payload: 44 37 2C 38 19 65 53 3C 16 8D 20 30 F1 36 BC 20 AD 5B 75 1A 64 AF 2F 6E FC B2 CA B5 62 6E B9 97 B9 81 21 CD 42 F9 10 CB 70 7D AB BE 24 35 41 F6 16 B4 2C 03 6C 5D A9 89 95 E1 B7 56 97 42 DA AC 39 80 91 D1 FE EA A4 9B 1B

Decrypted Plain Payload: 6F C4 78 04 FF 23 00 00 00 00 44 13 E6 E4 00 00 52 3B 5C 02 06 FF 1B 05 50 00 05 50 00 42 6C 41 34 61 67 0B 51 67 0D 02 3B EB 01 04 13 DD F3 00 00 81 01 E7 FF 0F 0D

Click here to expand the byte-by-byte table
Byte Index Value (Hex) Interpretation
0 6F Part of CRC Header (Byte 0 of 2)
1 C4 Part of CRC Header (Byte 1 of 2)
2 78 Application CI (0x78)
3 04 DIF_FF for Status Marker
4 FF VIF_FF for Status Marker
5 23 Manufacturer Code for Status Marker
6 00 Part of Status Value (LSB, 00 00 00 00)
7 00 Part of Status Value (Byte 1, 00 00 00 00)
8 00 Part of Status Value (Byte 2, 00 00 00 00)
9 00 Part of Status Value (MSB, 00 00 00 00) -> 0x00000000 OK
10 44 DIF for Total Volume
11 13 VIF for Total Volume
12 E6 Part of Target Volume (LSB, E6 E4 00 00)
13 E4 Part of Target Volume (Byte 1, E6 E4 00 00)
14 00 Part of Target Volume (Byte 2, E6 E4 00 00)
15 00 Part of Target Volume (MSB, E6 E4 00 00) -> 58.598 m³
16 52 DIF for Max Flow
17 3B VIF for Max Flow
18 5C Part of Max Flow (LSB, 5C 02)
19 02 Part of Max Flow (MSB, 5C 02) -> 604 L/h
20 06 DIF_FF for Manufacturer Marker
21 FF VIF_FF for Manufacturer Marker
22 1B Manufacturer Code for Manufacturer Marker
23 05 Part of Manufacturer Data (Byte 0 of 6)
24 50 Part of Manufacturer Data (Byte 1 of 6)
25 00 Part of Manufacturer Data (Byte 2 of 6)
26 05 Part of Manufacturer Data (Byte 3 of 6)
27 50 Part of Manufacturer Data (Byte 4 of 6)
28 00 Part of Manufacturer Data (Byte 5 of 6)
29 42 DIF for Target Date
30 6C VIF for Target Date
31 41 Part of Target Date (Byte 0 of 2)
32 34 Part of Target Date (Byte 1 of 2) -> 2026-04-01
33 61 DIF for Min Temperature
34 67 VIF for Min Temperature
35 0B Min Temperature -> 11 °C
36 51 DIF for Max Temperature
37 67 VIF for Max Temperature
38 0D Max Temperature -> 13 °C
39 02 DIF for Current Flow
40 3B VIF for Current Flow
41 EB Part of Current Flow (LSB, EB 01)
42 01 Part of Current Flow (MSB, EB 01) -> 491 L/h
43 04 DIF for Total Volume
44 13 VIF for Total Volume
45 DD Part of Total Volume (LSB, DD F3 00 00)
46 F3 Part of Total Volume (Byte 1, DD F3 00 00)
47 00 Part of Total Volume (Byte 2, DD F3 00 00)
48 00 Part of Total Volume (MSB, DD F3 00 00) -> 62.429 m³
49 81 DIF_FF for Ext. Metadata
50 01 VIF_FF for Ext. Metadata
51 E7 Manufacturer Code (Part 1)
52 FF Manufacturer Code (Part 2)
53 0F VIF_FF (Continuation) for Ext. Metadata
54 0D End Value / Extra -> 13

Badge

About

Arduino Skript to receive und decode Kamstrup FlowIQ 2200 wM-Bus telegrams

Topics

arduinocc1101espesp32flowiqflowiq2200home-assistanthomeassistantkamstrupmqttwmbuswmbusmeters

Resources

Readme
Activity

Stars

0 stars

Watchers

0 watching

Forks

0 forks
Report repository

Releases

Packages

Contributors

Languages