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Wireless "SOILSENS-V5W" and Wired "SOILSENS-V5"

The SOILSENS-V5W is a reliable wireless capacitive soil moisture sensor that utilizes ESP-NOW or Wi-Fi for connectivity. It includes a soil temperature sensor, an air humidity and temperature sensor, and a light intensity sensor. One of its key advantages is that the capacitive sensor electrodes are embedded within the inner layer of the PCB, providing protection. It boasts very low power consumption, a compact design, long-range capabilities in ESP-NOW mode, and configuration changes that can be made without the need for reflashing. Additionally, it supports MQTT Autodiscovery through CapiBridge in ESP-NOW mode or simple Wi-Fi, making it 100% compatible with Home Assistant.

🛒 Where to buy https://www.PricelessToolkit.com

📣 Updates, Bugfixes, and Breaking Changes

Note

If you're ready to contribute to the project, your support would be greatly appreciated. Due to time constraints, I may not be able to quickly verify new "features" or completely new "code" functionality, so please create a new code/script in the new folder.

• 10.11.2024 - Increased sensor calibration time to 60 seconds.
• 10.11.2024 - Added RSSI and raw moisture ADC values to MQTT payload.
• 24.07.2024 - Work in progress: "Implementing CRC for ESP-NOW."
• 22.07.2024 - Added the ability to configure the sensor through a Wi-Fi hotspot.
• 21.07.2024 - Combined WiFi and ESP-NOW firmware.
• 20.07.2024 - Implemented MQTT Autodiscovery in "WiFi Mode."
• 15.06.2024 - Published battery percentage.

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Product Specification

• Microcontroller:
  • ESP32-C3
• Sensors:
  • Soil Temperature: TMP102
  • Air Temperature and Humidity: AHT20
  • Light Sensor: ALS-PT19-315C
  • Soil Moisture: PCB Trace in the internal layer
• Power:
  • Uses 1S LiPo Battery "Connector PH2.0"
  • Requires external 1S LiPo charger
• Buttons:
  • PRG (Programming)
  • RST (Reset)
  • CAL (Calibration)
  • TRG (Trigger)
• LED Indicators:
  • Green LED: Indicates the power-on state
  • Blue LED: Indicates calibration/configuration mode
• Sensor Reading Interval:
  • Default: 1 hour
  • Configurable: 5m, 10m, 30m, 1h, and 2h
  • Configuration Method: Adjustable via onboard PCB solder jumpers

Required

• 1S 250mAh or less LiPo Battery (Connector PH2.0) 35x20x4mm MAX.
  • https://s.click.aliexpress.com/e/_Dk14vS5
  • https://s.click.aliexpress.com/e/_DE5PfEV
  • Adafruit 150mAh https://www.adafruit.com/product/1317

Warning

⚠️ Ensure the battery connector has the correct polarity, as batteries from China sometimes come with random polarity. If it’s incorrect, you can manually swap the wires by gently lifting the plastic retainer on the pin, pulling the wire out, and then reversing the polarity before reinserting it. Connecting the battery with reverse polarity will damage the sensor permanently. Double-check the polarity before connecting the battery.

Note

Lipo Polarity explanation "Adafruit Video" https://youtu.be/ILArrTIMFyM?si=WlTsnVo7XTozZ2FT

• 1S 4.20V LiPo charger.
  • Adafruit https://www.adafruit.com/product/1304

Warning

⚠️ Ensure the charger’s maximum charging current does not exceed the battery’s capacity. For example, if the battery is 250mAh, the charger should have a maximum charging current of 250mA or less. Also, check the charger’s polarity, as it can sometimes be reversed.

Initial Power On and Default Operation

• SOILSENS-V5W supports two modes: ESP-NOW and WiFi for MQTT-based connectivity.
• Upon powering on, the SOILSENS-V5W operates in ESP-NOW mode by default. This mode does not require any initial configuration and communicates directly with the Capibridge gateway. The default Gateway Key is "xy"

Feature	ESP-NOW	WiFi
Energy Efficiency	Highly energy-efficient	~3x Higher power consumption
Range	Long-Range	Short range
Configuration	Does not require configuration	Requires network and MQTT configuration
Broadcasting	Sensor data can be read from a third device without connecting to a network	Requires connection to a network
Gateway Requirement	Requires a gateway Capibridge	Does not require a gateway

Power consumption

Note

Measured using Power Profiler KIT 2 Battery Capacity 250mAh, Power Cycle 1h

Parameter	WIFI	ESP-NOW
Active Duration (seconds)	1.5 seconds	0.55 seconds
Current During Active Phase	47 mA	40 mA
Energy Consumption in Active Phase	0.02 mAh	0.006112 mAh
Inactive Duration	0.99956 hours	0.999847 hours
Energy Consumption in Inactive Phase	0.00007 mAh	0.00007 mAh
Total Energy Consumption	0.02007 mAh	0.006182 mAh
Total Hours of Operation	12,459 hours	40,445 hours
Total Days of Operation	519 days	1,685 days

1. Configuration

To access the configuration settings, follow these steps:

1. Initiate Configuration Mode:
   • Press and hold the calibration button.
   • While holding the calibration button, briefly press the trigger button.
   • Continue holding the calibration button for more than 3 seconds and release it.
   • The blue LED will blink five times, indicating the device has entered configuration mode.

Note

If you enter the wrong credentials or MAC address and the sensor stays on, preventing you from entering configuration mode again, follow these steps: disconnect the battery, press and hold the calibration button, reconnect the battery, wait for 5 seconds, then release the button. You should now be able to connect to the created hotspot and enter new credentials.

2. Access Configuration via WiFi:
   • After entering configuration mode, the sensor creates a WiFi Access Point (AP) named SOILSENS-V5W.
   • Connect to this AP using the default password: password.
   • Open a web browser and navigate to http://192.168.4.1 to access the configuration page.

Mode ESP-NOW	Mode Wi-Fi
Default Node name and key.	Only the key is not required.

3. Web Configuration:
   • Node Name: Enter a unique name for your sensor.
   • Gateway Key: Enter the key for the Capibridge gateway. for WIFI Mode not required
   • Mode: Select the desired mode:
     • 1 (ESP-NOW): Selects ESP-NOW Protocol "Long-Range".
     • 0 (WiFi): Selects standard WiFi and MQTT setup.
   • For WiFi mode:
     • WiFi SSID: Enter your WiFi network name.
     • Password: Enter the WiFi password.
     • MAC Address: Specify the Access point MAC address "9b:84:5a.....".
     • Local IP, Gateway, Subnet: Enter IP address ⚠️ "IP Address outside of DHCP Range".
     • MQTT Server, Port, Username, Password: Provide MQTT broker details.

After entering the necessary information, click Submit to save the configuration. The sensor will restart with the new settings.

Important

⚠️ Entering to configuration mode will erase all current settings. Therefore, if you enter configuration mode without saving any changes, all settings will revert to their factory defaults, such as ESP-NOW with Key xy.

2. Calibrating the Soil Moisture Sensor

Accurate soil moisture readings require proper calibration. Follow these steps:

1. Insert the sensor into the flowerpot, ensuring the soil is as dry as your plant can tolerate.
2. Press and hold the calibration button. Avoid moving the sensor to keep it securely embedded in the soil.
3. While holding the calibration button, briefly press the trigger button.
4. Continue holding the calibration button for less than 2 seconds, then release it.
5. The blue LED will blink twice, indicating the start of the "dry soil" calibration.
6. The device will complete the minimum moisture level calibration, indicated by three blinks.
7. You now have 60 seconds to water your plant to its maximum acceptable moisture level.
   • I recommend watering the entire soil surface for no more than 20 seconds, allowing it to soak in for 40 seconds.
8. After 60 seconds, the blue LED will blink twice, signaling the start of the "wet soil" (100%) calibration.
9. The device will complete the "wet soil" calibration, indicated by three blinks.

Note

To ensure accurate readings, avoid touching or moving the sensor after calibration to prevent loosening in the soil. If, over time, sediment accumulates in the soil, the Moisture MIN and MAX values may change.

Important

⚠️ Until the soil moisture sensor calibration is not performed, the sensor reading will be 0.

WiFi Signal Strength

Note

Ensure the Wi-Fi signal strength at the installation point is strong and stable.

RSSI (dBm)	Signal Quality	Description
-30 to -50 dBm	Excellent	Very strong signal, ideal for stable data transmission
-51 to -60 dBm	Good	Strong signal, generally reliable for data
-61 to -70 dBm	Fair	Moderate signal, some minor issues possible, but usable
-71 to -80 dBm	Poor	Weak signal, may experience some data drop
-81 to -90 dBm	Very Poor	Very weak signal, frequent data drop likely
Below -90 dBm	Unusable	No effective connection, likely out of range

3. Wake Up Interval

Solder Jumpers	interval selection
	You can change it by cutting the middle of the 1H Jumper. Then bridge the other jumper with the solder. Available intervals are 5m, 10m, 30m, 1h, and 2h, plus every combination is possible. Parallel Resistor Calculator

But if you are bored and want to play with different intervals you can change the resistor value.

Time Interval	Resistor Value (kΩ)	Time Interval	Resistor Value (kΩ)
1 min	22.00	10 min	57.6 - soldered
2 min	29.349	20 min	77.579
3 min	34.729	30 min	93.1 - soldered
4 min	39.097	40 min	104.625
5 min	42.2 - soldered	50 min	115.331
6 min	46.301	1 h	124.00 - soldered
7 min	49.392	1h 30min	149.398
8 min	52.224	2 h	169.00 - soldered
9 min	54.902

Note

Default time interval is 1 Hour. Reducing the time interval will result in increased energy consumption.

DIY

This project is open-source, enabling you to assemble SOILSENS-V5W yourself. To make this easier, I've included an 'Interactive HTML BOM File' in the PCB folder, which guides you on where to solder each component and indicates polarity, minimizing the chance of errors. I've invested a lot of time and money into making this project open-source. Your support, whether through buying a ready-made device from my shop www.PricelessToolkit.com subscribing to my YouTube channel, or buying me a coffee, is greatly appreciated and helps fund future projects.

Schematic

View schematic. Click here

Programming using Arduino IDE

1. • Open the provided code in the Arduino IDE.
2. • Install all neccecery libraries.

      
   #include <esp_now.h>
   #include <WiFi.h>
   #include "driver/adc.h"
   #include "esp_adc_cal.h"
   #include "Wire.h"
   #include <SparkFunTMP102.h>
   #include <ArduinoJson.h>
   #include <AHT20.h>
   #include <Preferences.h>
   #include <WebServer.h>
   #include <PubSubClient.h>
           

3. • Select the appropriate board and port parameters (refer to the provided screenshot for settings).

4. • Connect 3.3V USBTTL adapter to SOILSENS-V5W

Sensor Pin	Adapter Pin
TX	RX
RX	TX
3V3	3V3
GND	GND

5. • Press and hold the PRG button on the sensor.
6. • While holding the PRG button, connect the USB to TTL adapter to the USB port of your computer.
7. • Click on the Upload button to upload the code to the sensor.

3D-Printed Case

The ideal material for the case is transparent and UV-resistant. ASA "UV-resistant" or ABS in white is the best choice as it allows light to enter, enabling the luminance sensor to function properly. For indoor use, consider translucent PETG to increase the luminance sensor's range and opt for a 3D-printed case with vent holes to ensure proper function of the air humidity and temperature sensors. For outdoor use, a case without vent holes is recommended to prevent water ingress during heavy! rain. Glue for case https://s.click.aliexpress.com/e/_DcvGBY9

Frequently Asked Questions

Why is my sensor giving inconsistent readings?

Due to the capacitive sensing principle, readings can vary based on soil moisture, tightness, and insertion depth. Repeated insertions might loosen the soil, affecting subsequent readings.

Troubleshooting

• Holding the calibration button.
  • More than 3 seconds configuration mode.
  • Less than 2 seconds Calibration mode.
• When manually pressing the trigger button, the sensor may occasionally stay on and not power off if the button is not released quickly enough. If this happens, simply press the reset button.