Introduction
This RS485 soil temperature, humidity, and pH sensor supports a broad voltage power supply range (5-30V) and communicates data through the reliable MODBUS-RTU protocol, allowing for seamless integration into existing automated irrigation systems. It can be paired with an Arduino UNO and a TTL to RS485 expansion board for easy setup. By ensuring optimal pH, moisture, and temperature levels, this Anti-corrosion soil sensor helps prevent over- or under-watering and maintains nutrient balance for hydroponics and soil-less cultivation.

The protection level of the soil sensor is IP68, and it is vacuum-filled and sealed with black flame-retardant epoxy resin. The probe material is made of 316 stainless steel, which is rust-proof, waterproof, anti-corrosion, salt-alkali corrosion resistance, and long-term electrolysis resistance. It is more affected by the soil salt content. It is small, can be buried in the soil for a long time, and is suitable for various soil types.

Soil sensors are widely used in agricultural irrigation, greenhouses, flowers and vegetables, grassland and pastures, soil rapid testing, plant cultivation, scientific experiments, grain storage and the measurement of moisture content and temperature of various particulate matter.

Soil temperature has a direct impact on plant growth. Proper soil temperatures help promote plant root growth and the ability to absorb nutrients. Generally speaking, higher soil temperature is helpful for plant growth because it can increase plant metabolism, promote nutrient absorption and transport, and increase plant microbial synthesis capabilities, thereby promoting plant growth rate and yield.
In addition, appropriate soil moisture helps plant roots absorb water and nutrients and maintains water balance within plant cells. If the soil moisture is too low, plant roots will be limited in absorbing water, which can lead to plant dehydration, stagnant growth, or even death. Excessive soil moisture may cause hypoxia in plant roots, hinder normal respiration and nutrient absorption of roots, and thus affect plant growth and development. Soil pH, also known as "soil reaction". It is an acid-base reaction of the soil solution, which mainly depends on the concentration of hydrogen ions in the soil solution, expressed by the pH value. A solution with a pH value equal to 7 is a neutral solution; a solution with a pH value less than 7 is an acidic reaction; a solution with a pH value greater than 7 is an alkaline reaction. Soil pH can generally be divided into the following levels:

pH value Soil acidity and alkalinity
＜4.5 Extremely acidic
4.5-5.5 Strongly acidic
5.5-6.5 acidic
6.5-7.5 Neutral
7.5-8.5 alkaline
8.5-9.5 Strongly alkaline
>9.5 Extremely alkaline

• 5-30V wide voltage power supply
• RS485 output, can be used with Arduino
• High precision, fast response, and stable output
• Stainless steel probe can be buried in soil or water for a long time
• Resin vacuum filling and sealing, IP68 protection level

Specification: 

Power supply voltage: DC5-30V

Power consumption: 0.5W@24V

Output mode: RS485

Detection parameters: Temperature, Humidity, pH

Humidity parameters

             Measuring range: 0-100%

             Resolution: 0.1%

             Accuracy: 0-50%@±2%, 50-100%@±3%

Temperature parameters

             Measuring range: -40°C~+80°C

             Resolution: 0.1°C

             Accuracy: ±0.5°C

pH parameters

             Measuring range: 3-9PH

             Resolution: 0.1PH

Protection level: IP68

Probe material: anti-corrosion special electrode

Sealing material: black flame-retardant epoxy resin

Working temperature: -20°C~+60°C

Cable length: 2m

Size: 123*45*15mm