# 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…

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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.

Every value cites its sourceOfficial pinout

[Buy on Compoden](https://compoden.com/products/elecrow-crowtail-capacitive-moisture-sensor-v20-for-arduino-iot-0039)

## 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](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20plant%20moisture%20display%20with%20an%20ESP32%2C%20a%20capacitive%20soil%20moisture%20sensor%2C%20a%20small%20OLED%20display%20and%20a%20Crowtail%20cable%20I%20already%20own): 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](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20soil%20moisture%20data%20logger%20with%20an%20Arduino%20Uno%2C%20a%20capacitive%20moisture%20sensor%2C%20a%20data%20logger%20shield%20with%20a%20real-time%20clock%20and%20SD%20card%2C%20and%20a%20Crowtail%20cable%20I%20already%20own): 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](https://app.soldr.ai/?prompt=I%20want%20to%20build%20a%20plant%20watering%20reminder%20with%20a%20Raspberry%20Pi%20Pico%2C%20a%20capacitive%20soil%20moisture%20sensor%2C%20an%20active%20buzzer%20and%20a%20Crowtail%20cable%20I%20already%20own): 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](https://www.elecrow.com/wiki/crowtail-capacitive-moisture-v20.html), 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](https://www.elecrow.com/wiki/crowtail-capacitive-moisture-v20.html), 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](https://www.elecrow.com/crowtail-capacitive-soil-moisture-sensor.html), 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).

## Sources

- [link](https://www.elecrow.com/wiki/crowtail-capacitive-moisture-v20.html) (Elecrow wiki, Crowtail-Capacitive Moisture V2.0)
- [link](https://www.elecrow.com/wiki/image/8/8f/Crowtail-Capacitive_Moisture-V2.0-20190408-01.pdf) (Elecrow schematic PDF, Crowtail-Capacitive_Moisture-V2.0-20190408-01)
- [link](https://www.elecrow.com/crowtail-capacitive-soil-moisture-sensor.html) (Elecrow product page)