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nbolton / greenhouse

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Improved soil moisture sensor waterproofing #230

Closed nbolton closed 2 years ago

nbolton commented 2 years ago

The waterproofing applied is probably not watertight, and furthermore, probably causes a surface tension effect which retains more water than is actually in the soil. This is because of submerging the entire PCB and cutting away the rubber from the capitative area.

Re-apply the PlastiDip only to the edges of the PCB.

nbolton commented 2 years ago

Moisture sensor has gone bananas again.

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nbolton commented 2 years ago

Spray coated moisture sensor in lacquer and dipped edge in Plasti Dip increases the dialectic size (capacitive barrier) which increases the wet voltage by about 1V (1.6V to 2.7V). There is still enough of a difference between wet and dry (3.1V); diff is 0.3V to show if sensor is wet or dry. However, the reading is now much more sensitive. Now, #227 is more important.

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