Datos del aparato

Version 1 of 31 October 2026 · describes firmware 4.12.115 and app 1.0.0. This data sheet is part of your purchase contract, in the version published when you placed your order; you receive it with the order confirmation (Terms § 8a). The commitments under “What stays” apply for as long as we provide updates — at least five years from delivery, and for devices from the Kickstarter campaign at least until December 2032. Everything else describes the state of the firmware named here; what an update changes is shown in the update notice beforehand and in the next version afterwards. Earlier versions: hydrocommander.com/en/geraetedaten.

At a glance

• Where: on the device and in the app on your smartphone. On our server only if you switch on remote access — and there only connection data, no readings or histories.
• No account, no sale of data. Nobody but you receives your readings and histories — unless you switch on remote access or MQTT. The connections the device makes itself (time, weather, update check) are listed below under “What the device sends to the internet”.
• Access: display, app, export (CSV, PDF), local interface (JSON), MQTT.
• Delete: “Factory reset” on the device, remove the cloud pairing in the app, reset the app data in the app.

What stays

For as long as we provide updates — no update restricts this:

• Readings, histories and settings are stored on the device. Readings and histories only reach us or third parties if you switch on remote access or set up a transfer yourself, for example to your MQTT broker.
• The device remains operable on your Wi-Fi without the cloud service.
• You can export your readings in a common file format.
• You can delete your data on the device (settings, readings, histories, credentials) with “Factory reset”.

What data the device generates

Data	How long	Available via
Soil moisture per zone in percent, plus the sensor’s raw value	current value	display, app, interface, MQTT
Moisture history per zone	last hour per minute (until the next restart); 24 hours as hourly averages, 7 days as 6-hour averages, 30 days as daily averages	display, app, export, interface
Soil temperature per zone (probe in the sensor head) and its history	like moisture	app, export, interface
Water amount per zone: today, total, number of waterings; usage per day	totals until reset; daily usage for the last 30 days	display, app, export, interface; today and total also via MQTT
Tank level — calculated from the pumped amount, not measured	current level	display, app, interface, MQTT
Event list: waterings with amount in milliliters and messages (such as tank empty, leak detected, watering guard), each with zone and time	the last 60 events, until the next restart	display, app, export, interface
AI mode learning state and health score per zone	until reset	app, interface; health score also in the export and via MQTT
State of leak detection and watering guard	until released	display, app, interface
Settings: zones, watering schedules, custom presets, vacation mode, language, display, time zone	until you change them	display, app, interface
Network: Wi-Fi name and password, device name on the home network, access key (API token)	until changed or until factory reset	Wi-Fi name in the app; the device never outputs the password; only the display shows the access key
Weather (if switched on): place, coordinates, latest forecast for rain and temperature	place until changed; forecast until the next request	app, interface
Smart home (if set up): MQTT broker address, user, password	until changed	app (without password)
Remote access (if switched on): cloud ID and access key	until unpairing	app (status)
Technical: firmware version, device ID (the MAC address), restart counter and reason for the last restart, details of the last crash, pump current measurement	version and ID permanently; restart counter and reason also after factory reset; crash details until the next power loss; current measurement only live	display (Info & update), interface

There is no operating-hours counter for the pumps: every watering appears with its amount in the event list, and the device adds up the amounts. The serial number is only on the rating label, not stored in the device.

How often the device measures: The device reads the sensors about once per second; as the current moisture it shows the median of the last five readings. From these it builds the per-minute values of the last hour and the hourly, six-hourly and daily averages. Via MQTT, if set up, it sends every ten seconds.

When data is saved: settings immediately, water amounts and tank level every five minutes, the learning state hourly, the histories once a day and before every update. After a power loss, the history values of the current day may therefore be missing; the last hour and the event list start empty after every restart.

Size and format: everything the device stores permanently fits into its 64 KB data memory. The interface returns JSON; the app exports CSV and PDF.

Where the data is stored

• On the device, in its internal memory. With this firmware, the memory is not additionally encrypted — so reset the device with “Factory reset” before you pass it on.
• In the app on your smartphone: the device list (name, IP address, device ID, cloud ID if any), usage statistics for the last 90 days, cached histories, the collected history (daily averages of moisture and temperature per zone and the events, for a good year: 400 days, at most 5,000 events) and the app settings. The app keeps the access key in the operating system’s key store (Android Keystore, iOS Keychain). The app makes no backup of its own, Android data backup is switched off for it; on an iPhone, an iCloud or computer backup may include its data.
• On our server, only if you switch on remote access: cloud ID, device name, firmware version, time of the last connection and online status; the access key only as a hash. The server deletes connection events after 90 days. Whatever the app retrieves on the go — readings, histories, commands — it only passes through and does not store. Details: privacy policy, section 14.
• At your MQTT broker, if you set one up — you are responsible for it.

How to access your data

• Display: Home (zones, tank level), Events, Stats (1, 7 or 30 days); technical details under Settings → System settings → Info & update.
• App: the same values including histories, events and AI insights, also as a widget.
• Export in the app: tab “Stats” → “Export CSV” creates a table with the state of every zone (name, preset, stage, age, moisture, thresholds, target, health, water today and total, number of waterings, mode, sensor, daily limit, flow rate), usage for all days stored in the app (up to 90), moisture and temperature history per zone (24 hours, 7 days, 30 days) including the daily averages collected in the app, all collected events with dates and the watering schedules; this is how you back up the history, for example before changing smartphones. “PDF report” summarizes device, usage today, this week and this month, zones and weather. The file is created on your smartphone and you share it via the share menu; nothing is sent to us. “Clear app cache” removes statistics, histories, AI state and export files from your smartphone, “Remove device” does the same for that device.
• Local interface (advanced): HTTP on your home network, responses in JSON. You find the access key under Settings → QR / API token; every request carries it as Authorization: Bearer <token>. The main addresses: /api/status (all current values), /api/history?zone=0…3&hours=1…720 (histories), /api/events (event list), /api/stats/water (usage for the last 30 days), /api/zone/ai-insights (learning state). Example: curl -H "Authorization: Bearer <token>" "http://<IP address>/api/history?zone=0&hours=720". Without the access key, the device only returns device name, model, firmware version and device ID at /api/identify.
• MQTT (smart home, such as Home Assistant), if you set it up: every ten seconds per zone moisture, health score, water today and total, pump on or off and mode, plus tank level, remaining volume and vacation mode, under hydrocommander/<device ID>/…; optionally with TLS. Guide in the app: “Smart home (MQTT)”.
• Remote access (optional): the same values via the app on the go. Factory reset, updates, Wi-Fi, MQTT and diagnostic functions work only on your home network.

What the device sends to the internet

Where	When	What
time servers ptbtime1.ptb.de, pool.ntp.org	on every Wi-Fi connection, then regularly	your connection’s IP address
Open-Meteo weather forecast (only if switched on)	every 30 minutes	location coordinates rounded to two decimal places (about one kilometer); IP address
Open-Meteo place search (only when you search)	when you search, up to three requests	the place name you enter, language; IP address
hydrocommander.com, update check	three minutes after switching on, then once a day and when you open Info & update	only the IP address — no device ID, no version
hydrocommander.com, firmware download	only when you start an update	IP address
our cloud server (only if switched on)	permanent encrypted connection	cloud ID, access key, firmware version; then whatever the app requests
your MQTT broker (only if set up)	every ten seconds	the values listed under MQTT

The connections the app itself makes are described in the privacy policy (section 12).

Deleting

What	How	Effect
everything on the device	Settings → System settings → Factory reset	deletes settings, zones, histories, statistics, learning state, Wi-Fi credentials (also in the radio chip), access key, cloud and MQTT credentials and the location; the device creates a new access key and starts the setup again. The restart counter, the reason for the last restart and, until the next power loss, the details of the last crash remain.
statistics of a zone	app, zone: “Reset today’s usage”, “Reset total statistics”, “Reset plant data completely”; AI: “Reset learning table”	resets the respective counters or the learning state to zero
event list	cleared at every restart	—
individual moisture and temperature histories	not provided	only with factory reset
remote access	app: Settings → Cloud → “Remove cloud pairing”	deletes your entry and its events on our server immediately, and from the backups after 14 days at the latest. A factory reset alone does not remove the entry on the server; if the device does not connect for six months, we delete it automatically.
app	“Profile” → “Reset app data completely”, or uninstall the app	deletes device list, keys, statistics and settings on the smartphone; a cloud pairing on the device remains — remove it first
MQTT broker	wherever you run it	—

Before you pass on or dispose of the device: first remove the cloud pairing in the app, then run Factory reset on the device.

Security

The connection between app and device on your home network uses HTTP with an access key and does not leave your network; the cloud connection is encrypted. Firmware updates are signed and checked before installation. The display has no PIN: anyone who can operate the device sees the access key under QR / API token. If you create a new one there, every connected app loses access and a cloud pairing is removed. You receive software updates including security updates for at least five years from delivery, and for devices from the Kickstarter campaign at least until December 2032. To report a vulnerability, go to hydrocommander.com/en/security.

What may change

Everything else in this data sheet — which values the device generates, how long it stores them and the ways in which you retrieve them — may be changed by an update if there is a valid reason: the security of the device, a change in legislation or the discontinuation or change of a third-party service, such as the weather service. This does not cause you any additional costs, and if a way of access is discontinued, an equivalent one remains. What changes is shown in the update notice before you start the installation, and afterwards in the next version of this data sheet. Your statutory rights in the event of defects remain unaffected.

Who is responsible

Stemp Systems, owner Tobias Stemp, Büchlbergerstraße 12, 94121 Salzweg, Germany, support@stemp-systems.de. We do not sell data and do not pass your readings and histories on to third parties. Personal data is covered by our privacy policy (stemp-systems.de/en/datenschutz), which also explains how to complain to a supervisory authority.