Real devices to test against, without owning them#

Written 2026-10-13, from a question: are there sites, vendors' or others', that give free access to hardware's data, so fieldmesh can be tested before a farm has any? Each was tried, or its documentation read, on that day.

source	what it gives	access	in fieldmesh
openSenseMap	every reading of thousands of citizen stations, some with soil probes: on 2026-10-13, 19 had reported soil water in the last day, from TRUEBNER SMT50s and Dragino LSE01s	open REST API, no key; data under the Open Data Commons Public Domain Dedication and Licence 1.0	built: `tools/opensensemap_collect.py` reads a station's soil series into a log, through the quality checks
OpenSprinkler's own firmware, demo build	the real controller firmware, run on Linux with no hardware: its web API and its MQTT messages	GPL-3.0 source; `make VERSION=DEMO`, or its Dockerfile with `BUILD_VERSION=DEMO`	checked: the MQTT bridge's OpenSprinkler profile against what 2.2.1(6) published (`tools/fixtures/opensprinkler-demo-mqtt.log`)
Synoptic Data, Open Access	public weather networks' stations, current and past, including state mesonets' and SCAN's soil moisture	free account and token	not built; NRCS SCAN is already read directly (`tools/scan_collect.py`)
The Things Stack Sandbox	a LoRaWAN network server; its command line simulates a device's uplinks	free, for non-commercial testing	not built; the bridge's ChirpStack profile is the LoRaWAN path today
CWOP, through APRS-IS and findU	live reports of thousands of home weather stations, many of them Davis and Ambient	free	not built
ThingSpeak public channels	anyone's published channels, some with soil probes	no key for a public channel	not built: quality varies, and the soil channel found had stopped in 2019

Makers whose APIs need their own device or account, with no public demonstration found: Ecowitt, Davis WeatherLink, Tempest, METER ZENTRA Cloud, Onset HOBOlink. Their stations' local protocols are read already (sdk/station_adapters.py: Tempest's UDP broadcast, the WeatherLink Live's HTTP API, an Ecowitt gateway's custom upload), and those are tested against the makers' published examples.

What the first runs showed#

openSenseMap's LSE01 station labels its conductivity in ohms, which a conductivity is not. The reader leaves it out and says why, rather than guess a unit.
That LSE01 reads 2.1 to 2.4% soil water: very dry sand, or a probe out of the soil. It passes the health checks, being in range and moving. The soil advisory now tells a probe out of the soil by a reading drier than the bed's soil can be (built 2026-10-14, modules/soilwater): in a loam this one would be out of the soil, and in sand it cannot say. Its keeper has not said which soil it is in.
The SMT50's 34 readings in six hours, thinned to one each ten minutes, all passed.
OpenSprinkler's firmware published a station opening and closing with its duration, a rain delay set and cleared, and a program starting with its water level and its weather, sensor and total scales. The bridge parsed every one. It had not mapped the weather scale (wa), which its own description promised; it does now. The firmware's availability message is a plain word, online, not JSON. Changing the water level by hand and asking for a reboot published nothing in the demo build, so those topics are still unchecked.

Running OpenSprinkler's demo firmware#

git clone https://github.com/OpenSprinkler/OpenSprinkler-Firmware fw
cd fw && git submodule update --init --recursive
docker build --build-arg BUILD_VERSION=DEMO -t opensprinkler-demo .

Its own Dockerfile adds the Raspberry Pi package repository even for the demo; a smaller image is Debian with g++ make libmosquittopp-dev libssl-dev, make VERSION=DEMO, and the binary run as OpenSprinkler -d /data. The demo build serves HTTP on port 80, not the 8080 its README gives for the Raspberry Pi build. The default password is opendoor, sent as its MD5. MQTT is set with /co?pw=…&mqtt={"en":1,"host":…,"port":1883,"pubt":"opensprinkler",…}, and nothing is published until the notification options ife and ife2 enable it.