Lemongrass

Open source car telemetry for 24 Hours of Lemons.

Requirements

• Raspberry Pi running Raspberry Pi OS
• PiSugar 3 UPS
• USB OBD-II adapter
• An InfluxDB instance running v2.x
• Grafana to visualize the data

Services

This repo provides two long-running services that run on the pi:

Deployment and orchestration (docker-compose, telegraf for OS metrics, etc.) should be managed in a separate IaC repository, not here.

Lap Data

Setup

1. Get a Race Monitor API token https://www.race-monitor.com/Home/API

2. Add your token to a .env file (see .env.sample) and source it:

source .env

3. Get your race ID

We need a Race ID to get information for. Head to https://www.race-monitor.com/Live/Race while your race is live to get this easily from the URL.

4. Run the tool

Pull the latest image:

docker pull ghcr.io/wot-lemons/lemongrass:latest

Live Race

Docker — pass your credentials via an env file (see .env.sample). To pin to a specific version instead of latest, replace the tag (e.g. 1.2.3). Available tags are listed at ghcr.io/wot-lemons/lemongrass.

Note: CAR_NUMBER is required for live/monitor mode. Omit it for completed races to write laps for all competitors (fieldwide backfill).

docker run --rm -it --env-file .env ghcr.io/wot-lemons/lemongrass:latest lemongrass laps RACE_ID CAR_NUMBER -m -n

pip — install from PyPI and source your .env first (step 2 above):

pip install lemongrass
lemongrass laps RACE_ID CAR_NUMBER -m -n

uv — install from PyPI as a tool and source your .env first (step 2 above):

uv tool install lemongrass
lemongrass laps RACE_ID CAR_NUMBER -m -n

Or run ephemerally without installing:

uvx lemongrass laps RACE_ID CAR_NUMBER -m -n

Graceful exit: Press Ctrl-C at any time to stop monitoring cleanly (exits 130). The monitor also exits automatically when the race ends.

Real example:

docker run --rm -it --env-file .env ghcr.io/wot-lemons/lemongrass:latest lemongrass laps 166811 13 -m -n

2026-06-19 20:52:41,057 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Race/RaceDetails "HTTP/1.1 200 OK"
--------------------------------------------------------------------------------
Race 166811
Fast Friday Started: 2026-06-19 16:00:00
Seekonk Speedway   Ends: 2026-06-20 01:00:00
--------------------------------------------------------------------------------
2026-06-19 20:52:41,151 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Race/IsLive "HTTP/1.1 200 OK"
2026-06-19 20:52:41,152 - INFO - Race 166811 is currently live.
2026-06-19 20:52:41,251 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Live/GetSession "HTTP/1.1 200 OK"
--------------------------------------------------------------------------------
2026-06-19 20:52:41,252 - INFO - Current overall rankings.
--------------------------------------------------------------------------------
Empty DataFrame
Columns: [Pos., #, Class, Class Pos., Name, Laps, Transponder]
Index: []
--------------------------------------------------------------------------------
2026-06-19 20:52:41,365 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Live/GetRacer "HTTP/1.1 200 OK"
--------------------------------------------------------------------------------
Team: Jacob Burns Car Number: 13   Class: Legends Transponder: 13775638
Best Position: 2
Final Position: 1
Final Class Position: 1
Total Laps: 16
Best Lap: 6
Best Lap Time: 00:00:14.165
Total Time: 00:05:43.405
--------------------------------------------------------------------------------
Lap Position      LapTime FlagStatus    TotalTime
  1        8 00:00:14.572      Green 00:00:23.097
  2        5 00:00:14.458      Green 00:00:37.555
  3        4 00:00:14.389      Green 00:00:51.944
  4        3 00:00:14.258      Green 00:01:06.202
  5        2 00:00:14.313      Green 00:01:20.515
  6        2 00:00:14.165      Green 00:01:34.680
  7        2 00:00:14.258      Green 00:01:48.938
  8        1 00:00:14.391      Green 00:02:03.329
  9        1 00:00:14.437      Green 00:02:17.766
 10        1 00:00:14.299      Green 00:02:32.065
 11        1 00:00:14.248      Green 00:02:46.313
 12        1 00:00:14.260      Green 00:04:46.328
 13        1 00:00:14.194      Green 00:05:00.522
 14        1 00:00:14.251      Green 00:05:14.773
 15        1 00:00:14.322      Green 00:05:29.095
 16        1 00:00:14.310      Green 00:05:43.405
 17        1 00:00:14.291      Green 00:05:57.696
--------------------------------------------------------------------------------
2026-06-19 20:52:41,369 - INFO - Monitoring car 13...
--------------------------------------------------------------------------------
Lap Position      LapTime FlagStatus    TotalTime
  1        8 00:00:14.572      Green 00:00:23.097
  2        5 00:00:14.458      Green 00:00:37.555
  3        4 00:00:14.389      Green 00:00:51.944
  4        3 00:00:14.258      Green 00:01:06.202
  5        2 00:00:14.313      Green 00:01:20.515
  6        2 00:00:14.165      Green 00:01:34.680
  7        2 00:00:14.258      Green 00:01:48.938
  8        1 00:00:14.391      Green 00:02:03.329
  9        1 00:00:14.437      Green 00:02:17.766
 10        1 00:00:14.299      Green 00:02:32.065
 11        1 00:00:14.248      Green 00:02:46.313
 12        1 00:00:14.260      Green 00:04:46.328
 13        1 00:00:14.194      Green 00:05:00.522
 14        1 00:00:14.251      Green 00:05:14.773
 15        1 00:00:14.322      Green 00:05:29.095
 16        1 00:00:14.310      Green 00:05:43.405
 17        1 00:00:14.291      Green 00:05:57.696

Completed Race

You can retrieve info for a completed race too. Omit CAR_NUMBER to write laps for all competitors in the field (fieldwide backfill mode).

Docker:

# Single car
docker run --rm -it \
  --env-file .env \
  ghcr.io/wot-lemons/lemongrass:latest \
  lemongrass laps RACE_ID CAR_NUMBER

# Full field
docker run --rm -it \
  --env-file .env \
  ghcr.io/wot-lemons/lemongrass:latest \
  lemongrass laps RACE_ID

pip / uv:

lemongrass laps RACE_ID CAR_NUMBER   # single car
lemongrass laps RACE_ID              # full field

Persisting CSV output: lemongrass laps -o writes a .csv to the container's working directory (/data). The container runs as a non-root user, so that write stays inside the container and is lost on exit unless you mount a writable directory at /data. Bind mounts keep their host ownership, so pass --user to run as your host user — the CSV then lands in ./out owned by you:

mkdir -p out
docker run --rm -it --env-file .env \
  --user "$(id -u):$(id -g)" \
  -v "$(pwd)/out:/data" \
  ghcr.io/wot-lemons/lemongrass:latest \
  lemongrass laps RACE_ID CAR_NUMBER -o

Real example:

docker run --rm -it --env-file .env ghcr.io/wot-lemons/lemongrass:latest lemongrass laps 166429 852

2026-06-19 20:46:17,391 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Race/RaceDetails "HTTP/1.1 200 OK"
--------------------------------------------------------------------------------
Race 166429
The B.F.E. GP 2026 Started: 2026-06-12 10:00:00
High Plains Raceway   Ends: 2026-06-14 19:30:00
--------------------------------------------------------------------------------
2026-06-19 20:46:17,487 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Race/IsLive "HTTP/1.1 200 OK"
2026-06-19 20:46:17,488 - INFO - Race 166429 is not live. Monitor mode disabled.
2026-06-19 20:46:17,587 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Results/SessionsForRace "HTTP/1.1 200 OK"
2026-06-19 20:46:17,692 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Results/SessionDetails "HTTP/1.1 200 OK"
2026-06-19 20:46:17,797 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Results/SessionDetails "HTTP/1.1 200 OK"
2026-06-19 20:46:17,945 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Results/SessionDetails "HTTP/1.1 200 OK"
2026-06-19 20:46:17,948 - INFO - Rate limited: sleeping 59.34s [6/6 slots used over 60s window; oldest request 0.66s ago]
2026-06-19 20:47:17,422 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Results/SessionDetails "HTTP/1.1 200 OK"
2026-06-19 20:47:17,570 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Results/SessionDetails "HTTP/1.1 200 OK"
2026-06-19 20:47:17,794 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Results/SessionDetails "HTTP/1.1 200 OK"
2026-06-19 20:47:18,090 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Results/SessionDetails "HTTP/1.1 200 OK"
2026-06-19 20:47:18,314 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Results/SessionDetails "HTTP/1.1 200 OK"
2026-06-19 20:47:18,626 - INFO - HTTP Request: POST https://api.race-monitor.com/v2/Results/SessionDetails "HTTP/1.1 200 OK"
--------------------------------------------------------------------------------
2026-06-19 20:47:18,913 - INFO - Current overall rankings.
--------------------------------------------------------------------------------
Pos.   # Class  Class Pos.                             Name Laps Transponder
   1 852     A           1              Rusty Bottom Racing  351        D-34
   2   4     A           2         Sew So Fast - GC edition  349         C-2
   3 380     A           3                 Vice City Racing  349        D-20
   4   6     A           4               Stay Classy Racing  337         C-3
   5 177     B           1                     DadBodCarMod  336        D-11
   6  49     B           2             Broken Spokes Racing  334        C-20
   7 101     A           5            Smokey and the Bandit  333         D-1
   8  11     A           6          Whiskey + Doughnuts =É.  333      165002
   9 300     A           7                     World War Zx  331        D-14
  10 501     A           8            Vistabeam Racing Team  330        D-26
...
  75 779     B          33     Poorsche Club of America (R)   59        D-31
  76 333     B          34           Green Beret RacingÉ.II   53        D-19
  77  73     B          35                      Team HonDuh   23     5632016
  78  28     A          27             Liquid Mechanics (R)   11     6201404
  79 150     A          28                       NTD Racing    9         D-8
  80  35     C          17                         Passhark    8        C-13
  81  17     C          18                     Haiku Racing              C-6
  82  72                 1      Enforcement Motorsports (R)             C-25
--------------------------------------------------------------------------------
Team:        Car Number: 852  Class: A Transponder: D-34
Best Position: 7
Final Position: 1
Final Class Position: 1
Total Laps: 351
Best Lap: 214
Best Lap Time: 00:02:12.483
Total Time: 14:36:02.587
--------------------------------------------------------------------------------
Lap      LapTime Position FlagStatus    TotalTime
  1 00:02:25.450        6      Green 06:28:04.193
  2 00:02:24.449        5      Green 06:30:28.642
  3 00:02:24.332        5      Green 06:32:52.974
  4 00:02:26.745        5      Green 06:35:19.719
  5 00:02:23.508        5      Green 06:37:43.227
  6 00:02:23.444        4      Green 06:40:06.671
  7 00:02:24.004        3      Green 06:42:30.675
  8 00:02:43.345        3      Green 06:45:14.020
  9 00:36:18.582        7      Green 07:21:32.602
 10 00:02:23.425        7      Green 07:23:56.027
...
340 00:02:21.490        1      Green 14:09:37.216
341 00:02:26.332        1      Green 14:12:03.478
342 00:02:26.332        1      Green 14:14:29.810
343 00:02:24.485        1      Green 14:16:54.224
344 00:02:24.068        1      Green 14:19:18.222
345 00:02:21.403        1      Green 14:21:39.553
346 00:02:27.229        1      Green 14:24:06.782
347 00:02:28.195        1      Green 14:26:34.906
348 00:02:24.841        1      Green 14:28:59.674
349 00:02:20.867        1      Green 14:31:20.472
350 00:02:21.190        1      Green 14:33:41.592
351 00:02:21.065        1     Finish 14:36:02.587
--------------------------------------------------------------------------------

Race Management

The races subcommand provides tools for inspecting and managing race data stored in InfluxDB.

lemongrass races <subcommand> [args]

Examples

# List all stored races and their schema version status
lemongrass races list

# Delete a race (prompts for confirmation)
lemongrass races prune 144185

# Delete multiple races at once, skipping confirmation
lemongrass races prune 144185 120037 --yes

# Diagnose a lap count mismatch for car 252 in race 144185
lemongrass races diagnose 144185 252

Backfill Options

The backfill subcommand delegates to lemongrass race-backfill and supports these flags:

Note: --upgrade-stored is mutually exclusive with --start-date and --validate; combine it with --force to also re-fetch races already at the current schema.

Session Tracking

All lap points written to InfluxDB include a session_id tag corresponding to the RaceMonitor session ID. In Flux queries you can filter by session_id to isolate specific race segments (e.g. Day 1 vs. Day 2). Session metadata is stored in the race_sessions bucket.

Configuration

lemongrass is configured by an optional TOML file named by the LEMONGRASS_CONFIG environment variable, falling back to built-in defaults. Secrets (INFLUX_TELEMETRY_TOKEN, RACEMONITOR_TOKENS) are supplied via the environment and referenced by *_env keys in the file — environment variables are not used for any non-secret setting. Copy lemongrass.toml.sample to get started. See docs/CONFIGURATION.md for the full key reference.

Contributing

For development setup, running the test suite, and testing against a local InfluxDB stack instead of prod, see CONTRIBUTING.md.

Upgrading from v1.x

As of v2.0.0, the individual entry points (laps, telem, race-backfill, pisugar-monitor, race-diagnose) were replaced by a single lemongrass command. If you have the old package installed, update and prefix commands with lemongrass: