Does the MS01 work without a TH relay?

No. It is a passive probe: power and signal processing come from the host. The official host list is TH Elite (THR316D/THR320D) and TH Origin (THR316/THR320); without one there is nothing to plug it into.

How do I build auto-watering with it?

Probe into the soil, RJ9 plug into the TH relay, pump or solenoid valve onto the relay output. In eWeLink enable Auto mode and set a moisture threshold: below it watering starts, above it it stops.

Is it compatible with the old TH10/TH16?

They are not on the current compatibility list: this MS01 revision ships with an RJ9 4P4C plug for the TH Elite/TH Origin, while the TH10/TH16 use a 2.5 mm jack. Buy it for the new-generation modules only.

Is the stock 50 cm cable enough?

If the relay sits next to the bed — yes. For remote mounting there is the RL560 (RJ9) extension: an MS01 run can be extended to 10 m at most — that is the official limit for this probe (the THS01 allows 60 m).

Why capacitive instead of a cheap resistive probe?

On cheap resistive sensors the exposed electrodes oxidise in soil within a season and readings drift. The MS01's capacitive blade is sealed in plastic, does not corrode and holds its calibration under constant watering.

Can it stay outdoors all year round?

In summer — yes: IP55 handles rain and overhead watering. But the working range is 0 to +60 °C, so the probe comes out of open ground before winter; permanent submersion in water is not supported either.

Where do I see the moisture readings?

In the eWeLink app, on the card of the paired TH module (the TH Elite also shows it on its own display). By voice — via Google Assistant, which Sonoff lists officially: ask about the soil humidity and it answers with the current value.

Does the MS01 appear as a separate device in eWeLink?

No, the probe has no card of its own — it shows up as a moisture reading inside the TH module's card. That is why it needs no Wi-Fi and no account binding itself: plug it into the socket and the data flows.

Sonoff MS01 — soil moisture sensor, Moldova

Name: Sonoff MS01 soil moisture sensor RJ9 for TH Elite / TH Origin relays
Brand: Sonoff
SKU: SONOFF-MS01
Price: 409 MDL
Availability: InStock

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Compatibility

Works with these ecosystems

Ecosystems

eWeLink
Google Home

What it is, who it's for, what it does

About this product

Think of the MS01 as the measuring half of a two-part system — the deciding half is a Sonoff TH Elite (THR316D/THR320D) or TH Origin (THR316/THR320) relay. The 130 mm capacitive blade sits in the soil, the 50 cm cable with an RJ9 4P4C plug goes into the relay, and the probe draws its 3.3 V from the host — no batteries, no Wi-Fi of its own.<br><br>You set a threshold on the relay's card in eWeLink: below it the TH switches your pump or solenoid valve on, above it — off. Bought without a TH host the MS01 is useless, as there is nothing to plug it into and it never appears as a separate device in the app. The IP55 body shrugs off watering and rain, and an RL560 cable extends the run to 10 m.

Delivery
Delivery 50 MDL
Returns
14 days to return
Warranty
24 months

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CasaSmart essentials

What it works with, what it needs, what you can do

Verified compatibility

We test every device for these ecosystems. For non-standard integrations contact us before ordering.

Home Assistant
Zigbee
Matter
KNX
Wi-Fi

Install & requirements

What you need on your side and what we deliver.

Zigbee hub or Matter gateway for wireless variants
65 mm back-box or DIN panel for wired variants
Local setup on Home Assistant — included in install

Request install quote

Smart scenarios

Three typical automations we set up after the install.

01Morning: warm light + blinds up + climate at 22 °C
02Leaving: lights off, arm sensors, close the gas
03Evening: warm ambient + cinema scene

Where it works

Use cases

Outdoor

In a greenhouse outside Chișinău the MS01 sits in the bed while a TH Origin opens the drip-line valve once the soil dries below the set point.

Outdoor

Between weekend visits the MS01 + TH Elite + barrel pump kit waters the seedlings on its own, with readings visible in eWeLink from town.

Home

A probe in a big ficus tub shows in the app when it is time to water, and in summer the TH drives a small pump for balcony planters.

For the installer

Technical specifications

full spec · wiring · datasheet

Other

Measurement type: capacitive probe
Humidity range: 0–100 %RH

Connectivity

Compatible hosts: TH Elite (THR316D/THR320D), TH Origin (THR316/THR320)
Connector: RJ9 4P4C
Max. extension (RL560 cable): up to 10 m

Physical

Cable length: 50 cm
Probe dimensions: 130 × 30 × 13 mm
Weight: 28 g
Plastic fire resistance: V0

Power

Power: 3.3 (from TH module) V

Environment

Operating temperature: 0…+60 °C
Water and dust protection: IP55

Full device datasheet

Support

Frequently asked questions

Does the MS01 work without a TH relay?
No. It is a passive probe: power and signal processing come from the host. The official host list is TH Elite (THR316D/THR320D) and TH Origin (THR316/THR320); without one there is nothing to plug it into.
How do I build auto-watering with it?
Probe into the soil, RJ9 plug into the TH relay, pump or solenoid valve onto the relay output. In eWeLink enable Auto mode and set a moisture threshold: below it watering starts, above it it stops.
Is it compatible with the old TH10/TH16?
They are not on the current compatibility list: this MS01 revision ships with an RJ9 4P4C plug for the TH Elite/TH Origin, while the TH10/TH16 use a 2.5 mm jack. Buy it for the new-generation modules only.
Is the stock 50 cm cable enough?
If the relay sits next to the bed — yes. For remote mounting there is the RL560 (RJ9) extension: an MS01 run can be extended to 10 m at most — that is the official limit for this probe (the THS01 allows 60 m).
Why capacitive instead of a cheap resistive probe?
On cheap resistive sensors the exposed electrodes oxidise in soil within a season and readings drift. The MS01's capacitive blade is sealed in plastic, does not corrode and holds its calibration under constant watering.
Can it stay outdoors all year round?
In summer — yes: IP55 handles rain and overhead watering. But the working range is 0 to +60 °C, so the probe comes out of open ground before winter; permanent submersion in water is not supported either.
Where do I see the moisture readings?
In the eWeLink app, on the card of the paired TH module (the TH Elite also shows it on its own display). By voice — via Google Assistant, which Sonoff lists officially: ask about the soil humidity and it answers with the current value.
Does the MS01 appear as a separate device in eWeLink?
No, the probe has no card of its own — it shows up as a moisture reading inside the TH module's card. That is why it needs no Wi-Fi and no account binding itself: plug it into the socket and the data flows.

Same ecosystem

Works together

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Same category

Questions about this product?

A CasaSmart manager calls you within 1–2 working hours and answers anything — compatibility, install, alternatives.

+373 60 944 922

Updated: 13 June 2026· reviewed by CasaSmart Expert Team

Compatibility