Feature request: HOBO bluetooth sensors: MX802

Devices not yet supported
1

I’m trying to decode packets from hobo mx802 (conductivity/temperature/depth), sensor, but it sends 2 separate manufacturerdata packets, what does that mean? OMQ only sees one? IS it possible to get two manufacturerdata packets in OMG?
I caught some packets:
c5000d248655010028800012d9002241a5c4d2002ebb34
c5000d248655010028820012d9002241a57592002e3a23
c5000d248655010028820012d9002241a587e2002ebb0b
c5000d24865501002882 0012d9002241a5ac72002eb99f
c5000d248655010028800012d9002241a59402002ebaed
c5000d248655010028820012d9002241a601e2002eba82
c5000d248655010028800012d9002241a60e12002e3964
N: [ OMG->MQTT ] topic: home/OMG_s3_ant/BTtoMQTT/DF812076BF45 msg: {“id”:“DF:81:20:76:BF:45”,“mac_type”:1,“adv_type”:0,“manufacturerdata”:“c5000d248655010028820012d9002241a5d112002ebb40”,“rssi”:-75,“txpower”:0}
c5000d248655010028800012e2002241a62062002e3812

i took a screenshot of the hobo app and nrf connect
same packet with app screenshot

c5000d248655010028800012e2002241a62062002e3812

hobo app
hobo app922×2048 100 KB

c5000d248655010028800012d9002241a68822002eb9b9
same time from pc app

app2
app2488×177 19.8 KB

nfr
nfr921×816 124 KB

N: [ OMG->MQTT ] topic: home/OMG_s3_ant/BTtoMQTT/DF812076BF45 msg: {“id”:“DF:81:20:76:BF:45”,“mac_type”:1,“adv_type”:0,“manufacturerdata”:“c5000d248655010028820012d9002241a68822002eb9b9”,“rssi”:-88,“txpower”:0}

previously there was a hobo water level sensor whose packages were a bit shorter ( Feature request: HOBO bluetooth sensors - #23 by mortenx ) maybe it is possible to use the same decoder?

https://www.onsetcomp.com/products/data-loggers/mx80x?srsltid=AfmBOorx7FCxtHixmch68jNUMT0o3kFGfSf4z8kl5ZEiLdyF2BNFoVuu

3

Did some research and found some links
the packages are sent in two parts manufacturedata 1 and 2
no. 2 starts with 0D24 and contains temperature and water level and the 1 package contains conductivity

Step 1: Identify Packet Types

There are two main packet types:

  1. Main Packet (SpC + Salinity)

    • Length: ≥ 18 bytes

    • Does NOT start with 0x0D 0x24

    • Contains Specific Conductivity and derived Salinity.

  2. 0x0D24 Packet (Temperature + Water Level)

    • Starts with 0x0D 0x24

    • Contains Temperature and Water Level.

Decoding Specific Conductivity (SpC) and Salinity

  • Packet: Main packet (not starting with 0x0D24)

  • Bytes Used:

    • range = byte[10]

    • raw24 = 3-byte big-endian from bytes [11], [12], [13]:

      C++

      raw24 = (d[11] << 16) | (d[12] << 8) | d[13];

      Kuva rohkem ridu

  • Formula: Coefficients depend on range:

    • 0x3C: SpC = 0.0000025129 * raw24 - 0.06659

    • 0x3D: SpC = 0.00000875 * raw24 + 56.05

    • 0x3E: SpC = 0.0000432974 * raw24 + 220.83

    • 0x3F: SpC = 0.00014254 * raw24 + 948.09

  • Salinity (PSU):

    C++

    sal = 0.0005112271 * SpC - 0.020634286;

Decoding Water Level (WL)

  • Packet: 0x0D24 packet

  • Find last occurrence of 0x2E marker:

    C++

    for (int i = d.size() - 3; i >= 0; --i) {

    if (d[i] == 0x2E) { idx_2e = i; break; }

    }

    Bytes Used:

    • hi = d[idx_2e + 1]

    • lo = d[idx_2e + 2]

  • Formula (piecewise by HI byte):

    • Positive WL:

      • HI=0x3C: WL = 0.00008303 * lo + 0.00696416

      • HI=0x3D: WL = 0.00034656 * lo + 0.02532572

      • HI=0x3E: WL = 0.00126269 * lo + 0.10841701

    • Negative WL:

      • HI=0xBA: WL = -0.00000664 * lo - 0.00022680

      • HI=0xBB: WL = -0.00001773 * lo - 0.00186963

      • HI=0xBD: WL = -0.00029950 * lo - 0.04077561

      • HI=0xBE: WL = -0.00123225 * lo - 0.11652788

Decoding Temperature

  • Packet: 0x0D24 packet

  • Find marker 0x22:

    C++

    if (d[i] == 0x22) {

    range_id = d[i + 1];

    W15 = (d[i + 2] << 8) | d[i + 1];

    }

    Formula by range_id:

    • 0x41 (normal):

      • If W15 < 35905: Temp = 0.000246462 * W15 + 8.145427

      • Else: Temp = 0.000474552 * W15 + 0.524970

    • 0x40 (cold): Temp = W15 / 8150.64

    • 0x3F (deep cold): Temp = 1.2762578e-05 * W15 + 0.5776933

      hex2 = 0D248655010028820012E20022419D50B2002E3D44
      Indeks: Hex explanation

      ------ ---- -----------------------------

      0 0D ID

      1 24 ID

      2..8 86 55 01 00 28 82 00 (serial)

      9 12 ← battery

      10 E2 ← batteryXX (siin E2 → 0xE2 ≙ ~4 pulka; vt lävendid all)

      11 00 ← battery signatuur

      12 22 ← temp marker (0x22)

      13 41 ← T°C range_id = 0x41 (“normal” )

      14 9D ← W15 (LE16 bait 13: W15 = LE16(0x41, 0x9D))

      15 50 ( payload-baidid)

      16 B2

      17 00

      18 2E ← waterlevel marker

      19 3D ← HI (-indikaator waterlevel)

      20 44 ← LO (raw waterlevel bait)

      hex1 not “0D24”
      Indeks: Hex explanation

      ------ ---- -----------------------------

      0..9 .. not use

      10 3E range (conductivity )

      11 12 raw24[MSB]

      12 34 raw24[MID]

      13 56 raw24[LSB] → raw24 = 0x12 34 56 (BE)

      14.. .. payload