Capacitive soil moisture v1.2/v2.0
Also known as: capacitive soil sensor · soil moisture v1.2 · Garden & weather
The plant-watering sensor: capacitive sensing means no corroding electrodes (unlike the resistive junk), so a dollar probe plus an ESP32 waters the tomatoes all summer.
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At a glance
⚑ flag an error| Measures | soil-moisture |
|---|---|
| Accuracy | Relative moisture only — calibrate wet/dry per probe |
| Interface | analog |
| Supply | 3.3–5 V |
| Battery-viable | Yes (deep-sleep friendly) |
| ESPHome | Generic ESPHome component (adc/gpio) — adc |
| Typical price | $1-2 (street, varies) |
Compare all sensor modules in one table →
Clone check
HIGH clone risk. The most gotcha-dense $1 sensor in the hobby: clones ship an NE555 instead of the TLC555 (misbehaves at 3.3 V) and omit the 1 MΩ bleed resistor. If readings are stuck or supply-dependent, that's why. How to check what you received →
Good for
Gotchas to know
- The board edge and electronics are NOT sealed despite the marketing — conformal-coat the top and heat-shrink above the soil line or it dies in weeks.
- Readings are relative: calibrate each probe's dry/wet values and map to percent in ESPHome.
- Power it from a GPIO only while sampling — continuous power accelerates corrosion and saves battery.
- Avoid resistive (YL-69 fork) sensors entirely: electrolysis destroys them in weeks.
Wiring it up
Analog output: use an ADC1 pin (ADC2 fights with Wi-Fi), expect the ESP32's ADC to be nonlinear at the extremes, and calibrate in software. Any dev board with a spare ADC pin works.