$9.99reference price
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For anyone already building (or about to build) their own Arduino or ESP32 irrigation setup who needs the raw moisture sensor that's missing before the relay — not for someone looking for something ready to use with its own app or screen.
It's a small probe you bury in a planter's or garden bed's soil that tells a microcontroller (an Arduino or an ESP32 — the tiny "computer" you program yourself) how wet the soil is at that spot. Being "capacitive" means it measures a change in an electric field near the tip, without the metal ever touching the wet dirt directly — think of it like a metal detector that knows something's nearby without having to touch it. Old, cheap sensors (resistive ones) instead stick two bare metal pins into the soil and measure how much current flows between them: it works at first, but those pins corrode with constant moisture, the same way any bare metal left wet in the yard does, week after week.
You've built (or want to build) your own automatic watering setup for balcony pots with an ESP32 and one of this catalog's relays: this sensor is the piece that tells the ESP32 when the soil is actually dry, instead of watering on a fixed schedule without knowing if it's actually needed.
A small nursery or aquaponics setup monitoring several beds or trays at once wires several of these sensors (they come 5 to a pack) into a single ESP32's analog inputs, and that same microcontroller decides which zone to water through a relay like this catalog's 8-channel ELEGOO — all the monitoring centralized without paying for a sensor with its own WiFi at every single point.
Compared to a bare-metal resistive sensor that costs a couple dollars less, the real difference shows up after the first season: the resistive one starts giving false readings or stops responding within a few weeks of constant moisture because its electrodes corrode, while the capacitive one keeps reading correctly year after year without exposing any bare metal to the dirt. For a project you're going to leave buried all summer without checking it often, paying those extra cents for the capacitive version avoids the worst kind of failure: the one that doesn't warn you, it just silently stops watering because the sensor stopped reading correctly.
Songhe Capacitive Soil Moisture Sensor for Arduino/ESP32 — Corrosion-Resistant (5-Pack)
$9.99reference price
See current price on AmazonIt's a small probe you bury in a planter's or garden bed's soil that tells a microcontroller (an Arduino or an ESP32 — the tiny "computer" you program yourself) how wet the soil is at that spot. Being "capacitive" means it measures a change in an electric field near the tip, without the metal ever touching the wet dirt directly — think of it like a metal detector that knows something's nearby without having to touch it. Old, cheap sensors (resistive ones) instead stick two bare metal pins into the soil and measure how much current flows between them: it works at first, but those pins corrode with constant moisture, the same way any bare metal left wet in the yard does, week after week.
For anyone already building (or about to build) their own Arduino or ESP32 irrigation setup who needs the raw moisture sensor that's missing before the relay — not for someone looking for something ready to use with its own app or screen.
This is the missing piece in this catalog's DIY ladder so a moisture sensor can talk directly to your own relay (like the [1-channel module](/en/productos/B00VRUAHLE) or the [ELEGOO 8-channel module](/en/productos/B09ZQRLD95)) without depending on any app or closed factory ecosystem: a capacitive probe with a TL555 chip that outputs an analog voltage (0 to 3.0V) proportional to soil moisture, without exposing bare metal to the dirt like cheap resistive sensors do — that's exactly what avoids the corrosion that ruins those within a few weeks of permanent use. It runs on 3.3 to 5.5V, so it works with both an Arduino Uno (5V) and an ESP32/ESP8266 (3.3V) with no voltage divider needed. It ships as a 5-pack — useful for several pots or zones from a single microcontroller with enough analog inputs. $9.99 (23% off the $12.99 typical price), 4.3 stars, 227 reviews, in stock. Real limitation: it outputs a raw voltage number, not a ready moisture percentage — you have to calibrate it by hand (dunked in water vs. in open air) before the reading means anything in your code, and it has no screen, app, or alert of its own like this ranking's RAINPOINT or THIRDREALITY.
Compared to a bare-metal resistive sensor that costs a couple dollars less, the real difference shows up after the first season: the resistive one starts giving false readings or stops responding within a few weeks of constant moisture because its electrodes corrode, while the capacitive one keeps reading correctly year after year without exposing any bare metal to the dirt. For a project you're going to leave buried all summer without checking it often, paying those extra cents for the capacitive version avoids the worst kind of failure: the one that doesn't warn you, it just silently stops watering because the sensor stopped reading correctly.
The reference price is $9.99 on Amazon. It can change, so check the current price before buying.
Field glossary
So you can use the right vocabulary with a customer, a supplier, or a manual.
Uses a capacitive probe (more durable than cheap resistive ones, which corrode over time) and is designed to stay buried permanently ('leave-in'), not for spot checks. It requires a hub from the same manufacturer — without it, the sensor won't report real-time data, it only works as a local probe.
Comes with the WiFi hub included (unlike the standalone sensor above) and adds historical data logging and low-moisture alerts. It integrates directly with the RAINPOINT smart irrigation ecosystem — if you already have or plan to buy a controller from another brand, confirm it supports this integration before buying, since it's a closed ecosystem.
This is not a soil moisture sensor — it's a leak/flood detector meant to be installed near appliances, under a sink, or in the basement. The individual sensors do NOT talk WiFi directly to each other: they use a proprietary long-range radio (up to 1,804 ft) to a gateway, and it's the gateway that connects to your 2.4GHz WiFi and sends alerts via app/SMS/email. GoveeLife sells this same line in variants with and without the gateway included — confirm in the listing that the one you're buying includes it, unless you already have a compatible GoveeLife gateway from another product (H5059/H5830).
