EncoderHeads 2026

R tooling for the thermometry encoder heads deployed at Kohnen Station (Antarctica) and on the Greenland ice sheet.

Repository structure

EncoderHeads2026/
├── EncodingHeads.qmd          # Encoding documentation: binary → hex → physical units
├── rechner.qmd                # Message size / transmission budget calculator
├── update_all.sh              # One-shot: fetch all Cloudloop data + re-render all reports
├── fetch_cloudloop_greenland.R  # Greenland fetch: Cloudloop API → testdata/*.bin
├── meta/
│   └── HeadsUndKetten.xlsx    # Head and chain inventory
│
├── KohnenRecords_Analyse/     # Kohnen Station (Antarctica) — heads 03 & 04
│   ├── fetch_antarctic_cloudloop.R  # Kohnen fetch: Cloudloop API → data/results-api-full.csv
│   ├── decode_results3.R      # Decode from Cloudloop CSV export
│   ├── decode_combined.R      # Merge old + new CSV exports and decode
│   ├── head03_profile.qmd     # Analysis profile — head03 (35 nodes, modem 231709)
│   ├── head04_profile.qmd     # Analysis profile — head04 (25 nodes, modem 231710)
│   ├── explore_head04.R
│   ├── make_plots.R / plot_*.R
│   └── data/                  # Raw CSV exports and decoded results
│
└── Greenland2026/             # Greenland field campaign — heads 26-02…26-05
    ├── decode_core.R          # Shared decode + calibration functions (sourced by all docs)
    ├── decode_snowmelt_newgrip.qmd  # ← SnowMelt GRIP (IMEI 300434065508020): melt profile
    ├── decode_snowmelt_dye3.qmd     # ← SnowMelt Dye3 (IMEI 301434062008160): melt profile
    ├── decode_chain.qmd       # ← Doppelkette (IMEI 301434062008130): borehole depth profile
    ├── system_state.qmd       # ← Betriebs-Dashboard: Latenz (Uhr-Offset) & Batterie, alle 3
    ├── tape_experiment.qmd    # Black-tape solar-absorption experiment (SnowMelt)
    ├── derive_mean_calibration.R  # Universal mean lab-S4 fallback coefficients
    └── data/                  # Field decode outputs (tracked; filenames keyed by message time)

Instruments

Head	Modem	Nodes	Fields per node	Deployment
26-02	228680	24	NTC1, NTC2, TestSB	Greenland 2026
26-03	234047	24	NTC1, NTC2, TestSB	Greenland 2026
26-04	234048	20	NTC1, NTC2, GND	Greenland 2026
26-05	228679	20	NTC1, NTC2, GND	Greenland 2026
head03	231709	35	NTC1, NTC2, GND, P	Kohnen (Ant.)
head04	231710	25	NTC1, NTC2, TestSB, GND	Kohnen (Ant.)

Heads 26-02 and 26-03 are SnowMelt sensors with nodes at 4 cm vertical spacing (node 1 = deepest).

Updating data & plots (Cloudloop)

All live heads report through the Cloudloop API (the web CSV export truncates payloads at 128 B and must not be used). One command fetches everything and re-renders every report:

./update_all.sh

Auth: the API token is read from $CLOUDLOOP_TOKEN or cloudloop/.token (git-ignored — never commit it). Everything is idempotent: both fetchers dedup against data already on disk (Greenland by the embedded message timestamp, Kohnen by rewriting the full CSV), so re-running at any time is safe.

The script runs these four steps, which can also be run individually:

Step	Command (from repo root)	Output
1. Greenland fetch	Rscript fetch_cloudloop_greenland.R	new testdata/<IMEI>-rb*.bin
2. Kohnen fetch + decode	cd KohnenRecords_Analyse && Rscript fetch_antarctic_cloudloop.R && Rscript decode_combined.R	data/results-api-full.csv, data/decoded_head0{3,4}_*_combined.csv
3. Greenland reports	cd Greenland2026 && quarto render <doc>.qmd for decode_snowmelt_newgrip, decode_snowmelt_dye3, decode_chain, system_state	HTML reports + CSVs in Greenland2026/data/
4. Kohnen reports	cd KohnenRecords_Analyse && quarto render head03_profile.qmd head04_profile.qmd	head03_profile.html, head04_profile.html

The Greenland heads are identified by message size (225 = GRIP, 226 = Dye3, 231 = Doppelkette), the two Kohnen Things by latitude ≈ −75 and size (340 B + 54 B pair = head03, 284 B = head04) — Cloudloop Thing IDs are opaque.

Greenland field use

The decoder is field-driven and keyed solely by IMEI (the .bin filename prefix, e.g. 300434065508020-57.bin). Three heads send in parallel, each with its own report document sharing decode_core.R. IMEI ↔ Rockblock modem serial (payload-verified):

Head	IMEI	Rockblock device	Document
SnowMelt GRIP	300434065508020	234048 – Head_26-04	decode_snowmelt_newgrip.qmd
SnowMelt Dye3	301434062008160	228679 – Head_26-05	decode_snowmelt_dye3.qmd
Doppelkette (chain)	301434062008130	228680 – Head_26-02	decode_chain.qmd

Workflow:

1. Add .bin messages to testdata/ — normally via Rscript fetch_cloudloop_greenland.R (see above); alternatively from the Cloudloop e-mail attachment or a Rockblock CSV export in download/ (extract per IMEI; the CSV names devices by modem serial, see the table above).
2. Open the matching document in RStudio. BIN_FILE already globs all .bin for that IMEI; a vector of files renders a time series. (A hex payload can still be pasted into MSG1 / MSG2 in the SnowMelt docs instead.)
3. Render (Ctrl+Shift+K) → profile, diagnostics, and CSV(s) saved to Greenland2026/data/.

The head's n_nodes / fields / type / spacing / calibration come from head_config[[IMEI]] inside each document — never derived from the message body. Counts→°C use the per-sensor lab Steinhart–Hart fit where a calibration table exists, else the universal mean lab-S4 curve (derive_mean_calibration.R); the legacy Beta curve is kept only for diagnostics.

Expected .bin message sizes (two firmware variants — every field is 0x7C-separated or concatenated; a defective sensor can add a few bytes):

Device (IMEI)	Nodes × fields	sep (B)	nosep (B)
SnowMelt (300434065508020)	24 × NTC1/NTC2/TestSB	299	225
Doppelkette (301434062008130)	20 × NTC1/NTC2/GND/Pressure	311	229

Dependencies

install.packages(c("dplyr", "tidyr", "ggplot2", "lubridate", "patchwork",
                   "httr2", "base64enc", "readr", "purrr"))