You are here: start » interfaces » mh-sensor

Differences

This shows you the differences between two versions of the page.

--- interfaces:mh-sensor [2016/01/21 13:24] – [Flying Fish MH Sensor] darron
+++ interfaces:mh-sensor [2016/04/22 12:07] (current) – [Moisture detector] darron
@@ Line 2: / Line 2: @@
 <wrap right>
 {{:interfaces:mh-sensor.jpg?200}}
+\\ \\
+{{:interfaces:ivy.jpg?200}}
 </wrap>
@@ Line 7: / Line 9: @@
 and a pot to give both an analogue and digital (threshold) output.
-Various sensors configurations can be found which include an LDR, NTC thermistor, and
+Various sensor configurations can be found which include an LDR, NTC thermistor,
-two resistive water/moisture detectors.
+two resistive water/moisture detectors and more besides.
-The moisture detectors utilise a 2 pin header which can allow us to reuse the
+The water/moisture detectors utilise a 2 pin header which can allow us to reuse the
-comparator board for any particular device we have available. For example, the picture
+comparator board for any particular device we have available. For example, the top picture
 shows a flat style 10K thermistor along with the moisture detector kit.
+Due to the circuit's simplicity, the digital output tends to oscillate when the
+two inputs to the comparator have a similar magnitude.
 ===Schematic===
+This is a reversed engineered schematic, the capacitor values are unknown.
 {{:interfaces:mh-sensor.png?200}}
+===Moisture detector===
+After 3 months of use all I can say is this probe is mostly unusable, the
+resistance value appears to be make little sense until at least you notice that
+the probe is corroding. I have placed a second probe in the soil but this time
+I have insulated the probe header (the other rusted) and now have the probe
+against the inside edge of the pot rather than anywhere near the middle, maybe it will last longer...
+Conclusion. The moisture probes are a waste of time.

Differences

start

interfaces

advertisement

Toolbox