Crowtail capacitive moisture sensor 2.0: specs and pinout
A capacitive soil moisture sensor board from Elecrow (model CMS00810C) with a corrosion-resistant probe, an analog output and a 4-pin Crowtail connector. It senses soil moisture by capacitance, so it has no exposed metal electrodes in the soil. Its only connector is the 4-pin PH2.0 Crowtail socket and the package has no cable: a Crowtail cable, which is not sold here, is required for every idea below.
Specs
| Spec | Value | Source |
|---|---|---|
| Model | CMS00810C | source Description |
| Operating voltage | 3.3 V to 5 V | source Specification table |
| Output | Analog level on the OUT pin, read on an analog input (the wiki connects it to analog port A0); the output range is not given | source Usage step 1 and 4 |
| Interface | Crowtail-compatible 4-pin PH2.0 connector (J1 on the schematic: OUT, NC, VCC, GND) | source Product page: Features; schematic sheet 1 |
| Board dimensions | 102 mm x 23 mm x 8.2 mm (wiki); 23 mm x 102 mm x 7 mm (product page) | source Specification |
| Sensing method | Capacitive measurement of soil; corrosion-resistant material | source Product page: Description and Features |
| Calibration | Read the sensor value in air and in water over the serial monitor at 9600 baud and use those two values as the dry and wet limits | source Usage step 4 and 5 |
| Timer on the board | Schematic shows an ICM7555 timer, a 1N4148 diode, a 1 Mohm and 0.1 uF output filter and an optional regulator marked 662K/NC | source Schematic sheet 1 |
Power
| Value | Source | |
|---|---|---|
| Supply | 3.3 V to 5 V | source Specification table (no current figure is given) |
Pinout
Pin names are from the official Elecrow schematic (Crowtail-Capacitive_Moisture-V2.0-20190408-01) for the 4-pin connector J1; the order is as drawn from top to bottom, so check the order on the board before wiring.
| Pin | Function | Voltage | Notes | Source |
|---|---|---|---|---|
| OUT | Analog signal output | Up to the supply voltage (range not given) | J1 pin, as drawn on the schematic | source Schematic sheet 1, J1 |
| NC | Not connected | J1 pin | source Schematic sheet 1, J1 | |
| VCC | Power supply | 3.3 V to 5 V | J1 pin | source Schematic sheet 1, J1 |
| GND | Ground | J1 pin | source Schematic sheet 1, J1 |
Build with it
Project ideas for the Crowtail capacitive moisture sensor 2.0. Each link opens Soldr with the prompt filled in; Soldr assigns the pins, checks power and shows how to wire every part.
- ESP32 plant moisture display: Power the sensor from the ESP32's 3.3 V pin (inside its 3.3 V to 5 V range) so the output never goes above what the ESP32 analog input accepts. Calibrate in air and in water as Elecrow describes. Requires a 4-pin Crowtail (PH2.0) cable you already own (not sold here). If Wi-Fi is on, read the sensor on an ADC1 pin (GPIO32 to 39).
- Uno soil moisture logger: The Uno runs the sensor at 5 V and reads the analog output. Each reading is stamped by the shield's clock and written to the SD card, so you can see how fast a pot dries. Requires a 4-pin Crowtail (PH2.0) cable you already own (not sold here).
- Plant watering reminder: Power the sensor from the Pico's 3.3 V pin and read it on an ADC pin. The reminder sounds when the reading passes the dry limit you recorded in air; it is a reminder, not an automatic watering system. Requires a 4-pin Crowtail (PH2.0) cable you already own (not sold here).
Common mistakes
- Skipping calibration: Elecrow says a calibration process is required first; read the value in air and in water and put those two numbers in the sketch instead of the example values 600 and 360 (source: link, Usage steps 4 and 5)
- Powering it above 5 V: the specified operating voltage is 3.3 V to 5 V, so do not use a 9 V or 12 V rail (source: link, Specification)
- Expecting a ready cable in the box: the product page's package list shows only the sensor, and the 4-pin PH2.0 connector needs a Crowtail cable or matching wires (source: link, Package list)
Not covered by the official source
- No current draw, output voltage range or accuracy figure is given by Elecrow.
- Board size differs between the wiki (102 x 23 x 8.2 mm) and the product page (23 x 102 x 7 mm).
- The schematic's regulator is marked '662K/NC' and the output filter values are drawn, but the document gives no output-versus-moisture curve.
- Every idea needs a Crowtail cable you already own (not sold here).