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Stainless Steel soil moisture sensor

We designed and built this sensor specifically to address the issues of corrosion of the probes, the exposed circuit and the exposed electronics components normally seen on this type of device.

IMG 1499  IMG 1502  IMG 1503 

The sensor is available as a kit of parts shown above, or as a fully assembled, tested and encapsulated product shown below connected to a Kitten board

  MG 1540  


Firstly the probes are 4mm diameter, 316 Stainless steel with 318 washers and nuts - 316 SS will not corrode or degrade in any way in even the most acidic soils. Compare this with the printed circuit board style of sensor with exposed copper or nickel plating which corrodes very rapidly in real world situations and may deposit copper into the soil.

Secondly, the circuit board itself is GOLD plated to inhibit any corrosion from soil or water contact. This is a "long-life" sensor !

Thirdly, you can at your option use a silicone conformal coating to repel moisture (e.g. Scotchgard type) or you can encapsulate the head of the device with a ureathane or epoxy resin to protect the components. Alternatively, we can provide a fully assembled, encapsulated device for the most durable commercial solution (SGH-SSM-003).


  • 5.0 volt or 3.3 volt operation
  • Analog signal
  • Precision electronic components, all through-hole for easy assembly
  • 316 stainless steel probes, 3" long
  • Gold plated circuit board
  • CATkit and Kitten compatible
  • 36 inch (950mm) 3 pin cable supplied (signal/power/ground)
  • Head size 1.85"L x 0.85"W x 0.25"D (48mm x 22mm x 7mm)

 SKU:  SGH-SSM-001        Sensor kit of parts, ziplock packaging

 SKU:  SGH-SSM-002        Sensor kit of parts, clamshell display packaging

 SKU:  SGH-SSM-003        Fully assembled, tested, encapsulated, clamshell display packaging

Resources       SGH_SSM.ino code   SSM_Instructions.pdf