Research-Grade Substrate EC, TDS and Temperature Sensor

HITA E0

HITA E0 sensor measures temperature and electrical conductivity (EC) of substrate, and fertilizer/nutrient solutions. The HITA E0 sensor comes in two different varieties having either standard tip, or a modified sharper tip for easy installation in rockwool. When used with DurUntash readout devices, EC measurements are automatically converted and reported in total dissolved solids (TDS) and an automatic algorithm compensates sensor EC readings for any temperature effect. The HITA E0 is optimized for continuous measurements in soilless growing media (e.g. rockwool, coco). The HITA E0 has extremely low power consumption and every sensor comes with a unique 64-bit digital ID making it ideal for IoT applications. It can be used for measuring salinity levels in fertilizer tanks and aquariums or or to prepare nutrient solutions in hydroponics. The HITA E0 sensor can be easily interfaced with the Raspberry Pi using DurUntash sensor adapters.

Features

  • Measures, electrical conductivity (EC), total dissolved solids (TDS) and temperature

  • Optimized for continuous bulk EC measurements in rockwool and coco coir

  • Measures salinity levels in fertilizer tanks and aquariums

  • Amperometric sensor; uses alternating current

  • Large electrode measuring surface area increases accuracy

  • Temperature measurements and temperature-compensated readings (when used with DurUntash readout devices)

  • Highly accurate; comes pre-calibrated for EC range of 0.1 - 3 dS/m

  • Ruggedized design; electronics protected by epoxy fill

  • Dedicated readers, wireless nodes, data loggers and configuration software

  • Ideal for IoT applications: 64-bit digital ID and very low power consumption

  • Easily interfaced with Arduino and Raspberry Pi

HITA E0 Electrical Conductivity, TDS and Temperature sensor for rockwool, coc coir, soil

Measurements in Soil, Rockwool, Coco Coir and Nutrient Solutions

You can use the HITA E0 sensor in a variety of applications. For example, you can use it for measuring salinity levels in fertilizer tanks, preparing nutrient solutions, and even EC or TDS measurements in aquariums. In addition to the EC, TDS and temperature of your nutrient solution, you can measure the electrical conductivity of your soil and soilless media directly using the HITA E0 sensor. The EC that is measured this way is called "bulk" EC, which is different than pore water EC or solution EC. Bulk EC readings, however, can be converted to both using mathematical models. 

HITA E0 EC, TDS and temperature sensor

Amperometric Sensor

The HITA E0 uses alternating current at a frequency optimized for bulk EC measurements. The current is applied through two carbon ink electrodes. The amount of current that passes between the two electrodes is a function of the salts present in the soil or liquid and is translated into the resistance between the electrodes. Electrical conductivity is then calculated as the inverse of the resistance multiplied by a value referred to as "cell constant". ​

Sensor Varieties

The research-grade HITA E0 sensor comes in two different varieties having either standard prongs, or modified sharper prongs  for easy installation in rockwool. The two sensor varieties share the same hardware. Both sensor varieties come pre-programmed with sensor-specific calibration coefficients for an EC range of 0.1 - 3 dS/m. This makes the research-grade sensor great for scientific research and allows it to work smoothly with DurUntash Lab data acquisition systems. 

Calibrated EC Measurements

​Sensor-Specific Calibration. Each HITA E0 sensor has a non-volatile memory, which allows for storing sensor-specific calibration coefficients. This allows for individual sensor calibration and minimizing sensor-to-sensor variations. Every time that a sensor is read, these sensor-specific calibration coefficients are automatically applied to EC readings.  

General Sensor Calibration. To make sure EC is measured with the highest accuracy within 0 - 3 dS/m range (of interest in most field, greenhouse and nursery applications), we have carried out numerous tests with the HITA E0 sensors and developed a general. The coefficients are stored on the dedicated reader or data logger, and automatically applied to sensor readings whenever a measurement is taken.

Temperature-Compensated EC Readings

Substrate/soil temperature (Ts) is a useful parameter in monitoring crop growth. It is also a key factor contributing to the inaccuracy of EC measurements, because Ts changes sensor readings. It is also known that electrical conductivity increases by about 1.9% per degree centigrade increase in temperature. This can cause EC to Go Up when the substrate/soil EC is actually decreasing and vice versa. It is worth knowing that sensor temperature sensitivity also affects the calibration process and contributes even more to the inaccuracy. This is why we have added an accurate temperature sensor to our design to measure Ts and account for its effect on EC.

TDS Measurements Based on 442 Natural Water™ Standard

TDS stands for Total Dissolved Solids and quantifies the concentration of dissolved solids in a nutrient solution. TDS is argubaly a more suitable parameter than EC for measuring nutrient concentration, considering it quantifies the amount of nutirents rather through the implication of conductivity. DurUntash readout devices use a variable conversion factor to automatically convert EC reading to TDS. The factor is calculated based on the 442™ curve for natural water. The 442™ part refers to 40% sodium sulfate, 40% sodium bicarbonate, and 20% sodium chloride mixed with deionized water.

Dedicated Reader, Data Logger & Graphical User Interface

To give the user the best experience, we have developed a graphical user interface (SHUSHAN CVI), which can be used for both sensor readings and real-time datalogging and monitoring. The sensor output signal is compatible with most commercial data loggers, but we recommend our SHINAK 4P 4-channel sensor node (series) that is available in standalone and wireless models. You can also take sensor readings using our ISHTAR 1P-BLE Bluetooth-enabled sensor node. If you are interested in electronics and DIY, we also have open-source sensor readers that you can build at home.

HITA E0 Electrical Conductivity Sensor
Datalogger
ISHTAR 1P-BLE

Optional Cable Length

The HITA E0 is available in three standard cable length options: 1.8 m (6 ft), 3.0 m (9.8 ft) and 4.5 m (14.8 ft). The cable length can also be easily extended using 1.8-m, 3-m, and 4.5-m extension adapter cables available from third-party sellers. Please read the HITA E0 user manual for more information.. 

Protective Case

The HITA E0 with 1.8-m cable comes with a protective clear plastic case for storing the sensor when it is not used. Using the case is a great (and inexpensive) way to protect the sensor electrodes against accidental damage, and contamination as a result of contact with oily hands or other substances that are non-conducting.

EC, TDS, temperature sensor

Great for IoT Applications

A measurement time of about 35 ms, low-power requirements (3 mA @ 3.3 V), and a 64-bit digital ID stored in its on-board ROM make the HITA E0 an excellent choice for Internet of Things applications. In applications, where small battery is the only source of power, and hundreds of sensors may operate on the same network, our HITA E0 can save the user a lot of headaches.

Image by Markus Spiske

Applications

Hydroponics

Electrical conductivity (EC) measures the ability of a solution, soil or substrate to conduct an electric current and it is directly related to the amount of salts available in the solution. The higher the amount of salts, the higher the EC. Daily EC measurements can tell you if your solution has lost water or nutrients. You can adjust high EC by adding water and low EC by adding more nutrients. In addition, adjusting the pH affects EC measurements because the conductivity of ions determining pH is much higher than others. So, EC measurements can help you recreate the same solution that has worked for you at specific pH level.

 

Avoid Over Fertilizing Your Plants

The danger of over-fertilizing plants is a lot more serious than when your plants are not getting enough. You can use an EC sensor to quickly tell whether there is too many nutrients in the solution, soil or substrate. So, avoid burning your plants by ensuring that the EC is within the recommended range.

Automated EC Measurements

The HITA E0 is ideal for IoT applications, and automatic fertigation systems in controlled environment agriculture.  We recommend using our EC meter to accurately and continuously measure the availability of nutrients to your plants by directly installing the sensor in the soil or substrate.

California Proposition 65 Warning

This product may contain chemicals, which are known to the State of California to cause cancer, birth defects or other reproductive harm. Please go to the proposition 65 warnings website for more information.