- Overview
- Specification
- Product Resources How to Buy
Zoom 
Testimonials
Lecturer in Physical Geography
University of Newcastle
Choosing equipment that you have complete trust in to record the data you need, and, importantly, technical backup when challenges arise, were fundamental requirements for us. When you are running out of time (and daylight) in a remote banana field it was reassuring that someone at Delta-T was responding so quickly to our technical questions.
The Delta-T devices kit has been first class – it has not missed a beat since we installed the equipment. We now plan to leave the SM150T sensors in-situ after the project to continue developing our understanding of the soil-water fluxes under banana crops." Prof Jerry Knox
Cranfield Water Science Institute,
Cranfield University, UK
Bern University of Applied Sciences
- Complete low-cost kit
- ± 3% accuracy
- Portable and easy to use
The SM150 Soil Moisture Kit provides an affordable and easy-to-use tool for obtaining reliable moisture measurements with minimal soil or substrate disturbance.
Introduction
The kit comprises an SM150T* Soil Moisture Sensor, a dedicated HH150 Moisture Meter and a carry case. The cable and connector are watertight – an essential requirement for potentially wet environments.
The HH150 Meter displays volumetric water content (% volume). Please note that although the SM150T Sensor has a built-in temperature sensor, the HH150 Moisture Meter does not measure or display temperature.
Simple operation
The HH150 hand moisture meter is lightweight and is very easy to use, being a readout-only device (no data recording or PC complications). Operation is simple – just insert the SM150T into the soil or substrate and press the Read button to make a reading.
Horticulture applications
The SM150 Kit comes with substrate calibrations for mineral, peat mix, coir, mineral wool and perlite (plus also provides raw voltage output) – providing a rapid, rugged solution for checking the uniformity of growing conditions for many types of growing media.
The SM150T is easy to insert and install – its sharp pins minimise soil disturbance and preserve the original soil structure around the measurement rods.
Other Delta-T soil moisture kits
Two alternative Delta-T Devices moisture measurement kits are available if greater accuracy or electrical conductivity (EC) measurements are required.
*The SM150 Kit was previously supplied with the SM150 Sensor, but now comes with the SM150T Sensor.
Specification
| Measurement | Volumetric water content and soil temperature |
| Accuracy | ± 0.03 m3.m-3 (3%) With soil-specific calibration |
| ± 0.5°C (0 to 40°C for temp sensor) ± 0.75°C (-20 to +60°C for temp sensor) | |
| Soil moisture measurement range | Full accuracy over: 0 to 0.7 m3.m-3 |
| Full range : 0 to 1.0 m3.m-3 | |
| Salinity range | 50 to 500 mS.m-1 |
| Salinity errors < 0.035 m3.m-3 from 0.05 to 0.4 m3.m-3. Can be calibrated up to 2000 mS.m-1 | |
| Temperature range | Full accuracy over: 0 to 40°C |
| Output | 0 to 1.0 V differential Corresponding to 0 to ~0.6 m3.m-3 |
| Resistance 5.8Ω to 28Ω for temp sensor | |
| Power requirement | 5-14 V, ~18 mA for 1s |
| Minimum 5 V with 100 m cable | |
| Environmental | IP68 (-40 to +70°C) |
| Sample volume | ~55 x 70 mm diameter |
| Sample volume is weighted towards soil immediately surrounding the rods | |
| Dimensions and weight | Overall: 143 x 40 mm diameter Rods: 51 mm x 2.5 mm diameter Weight: 0.1 kg (exc. cable) |
| Sensor calibrations | Individual sensors are interchangeable Recalibration advised every 3 years (depending on use) |
| Soil calibrations | Mineral, peat mix, coir, mineral wool, perlite - and also raw voltage output |
| HH150 Meter | |
| Accuracy | 0.5% of full scale over 5-40 °C (±7.5mV – negligible effect on SM150 accuracy) |
| Resolution | 0.1% of voltage reading |
| Battery life/standby life | 2 x GP alkaline AAA/ 10000 readings/1 year |
| Environmental | Non-condensing |
| Compliance | CE, FCC & ROHS |
Accessories
Hardware
Main components and software
Mountings and enclosures
Installation accessories
Cables and networks
Remote communications
Spares and consumables
Power options
Other
Product Resources
Data Sheets
- SM150T System Integrator Data Sheet 3 MB
Filename: SM150T_System_Integrator_data_sheet_v.1 - Soil Moisture Measurement Catalogue 14 MB
Filename: Soil_Moisture_Measurement_Catalogue_ver_5
Case Studies
- Cranfield University - Using SM150T to improve banana irrigation management in ColombiaDownloadFilename: →
- SM150T Soil Sensor used by Rothamsted Research for major experiment 3 MBDownloadFilename: Case_Study_Delta-T_Rothamsted_2021
- NIAB EMR's WET Centre uses Delta-T soil moisture sensors to achieve record yields 3 MBDownloadFilename: NIAB_EMR_WET_Centre_Case_Study_ver_20_02_2021
- Seven brief Delta-T Devices soil moisture sensor case studiesDownloadFilename: →
- Newcastle University uses SM150T in Iceland erosion research - case study 3 MBDownloadFilename: SM150T_Iceland_erosion_case_study_Newcastle_Uni_v.1
Videos
Manuals
FAQs
- Are Delta-T soil moisture sensors waterproof? Can they be buried? (SM150T ML3 ThetaProbe)
Question
I see that the environmental protection rating for Delta-T soil moisture sensors is IP68. In practical terms what does this mean for the performance of the sensors and their cable connections, and can they be buried?
Answer
The IP68 Standard
The IP standard defines the degree of protection against the entry of water and dust that an instrument has. The first digit corresponds to performance for dust protection, the second figure for the level of water resistance. A rating of IP68 means that a device is completely sealed against dust and that it can withstand complete and continuous submersion in water. More information on the standard can be found here: https://en.wikipedia.org/wiki/IP_Code.
When Delta-T develop products for use in the field, we not only aim to meet the requirements of relevant IP standards, but, where possible, to surpass them. Our product design and testing aims to establish the highest performance we can achieve for the sensor and the cable connection.Sensor sealing
During the design of the *SM150, SM150T, *SM300 and ML3 sensors, extensive water resistance tests were performed with reference to IP68 standards. Thermal shock tests were also carried out, which involved continuously monitoring the humidity inside the sensor as it was subjected to temperatures above 100OC before being plunged into ice cold water. It was demonstrated that, even under these harsh ‘shock’ regimes, the sensors showed no signs of water ingress.M12 connector sealing
During the design stage of the ML3 ThetaProbe (our most recently released sensor) we completed a comprehensive range of tests on the M12 cable connector (also fitted to several other Delta-T soil moisture sensors) to ensure satisfactory water resistance when submerged in water at depth.These tests will continue and results made available. Test results so far indicate that the M12 connection with the soil sensor can withstand burial to a depth of 2m – providing care is taken to ensure the connectors are clean and dry when assembled, and that they are hand-tightened securely.Routine production testing
*SM300s, *SM150, SM150T and ML3 sensors are batch tested using the hot water leak test – which involves submerging a proportion of sensors from a manufacturing batch in a 60°C water bath for a fixed time whilst checking for bubbles emerging from the sensor or connector. In terms of pressure, this treatment is comparable to an immersion in 1.4m depth of water. We have determined that this an acceptable test to discover assembly errors.
5 year warranty
All Delta-T products will benefit from a 2 year warranty. However, for additional peace of mind, once you have registered your SM150T or ML3 soil moisture sensor with us, the warranty increases from 2 years to 5 years.*SM300 and SM150 are now discontinued
Technical Notes
- Ground Instrumentation for GIS and Earth Observations: Soil Moisture & Temperature 8 MBDownloadFilename: Aberystwyth GIS poster – version 1
Regulatory Information
- SM150_2004_108_EC_certificate 59 KBDownloadFilename: sm150_2004_108_ec_certificate