SoilHumiditySensor: Difference between revisions

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* probe AOUT (yellow) to Wemos D1 mini pin A0
* probe AOUT (yellow) to Wemos D1 mini pin A0


This way, the wire with the 3-pin connector can simply be plugged into the Wemos D1 mini, without having to modify the cable.
This way, all connections on the Wemos D1 are right next to each other and the wire with the 3-pin connector can simply be plugged into the Wemos D1 mini without having to modify the cable.


The software puts a low level on pin D5 (to emulate GND) and a high level on pin D0 (to emulate VCC).
The software puts a low level on pin D5 (to emulate GND) and a high level on pin D0 (to emulate VCC).
The idea is that the operating current of the probe is low enough for this trick to work.
The idea is that the operating current of the probe is low enough for this trick to work.
I put heatshrink wrapping around the top part of the probe, to protect the electronics from moisture.


== Software ==
== Software ==

Revision as of 15:33, 12 May 2019

Project SoilHumiditySensor
SoilHumiditySensor.png
Investigation of soil humidity sensors
Status In progress
Contact bertrik
Last Update 2019-05-12


Introduction

A number of types of soil humidity sensors exist. Many have the problem that the electrodes corrode.

For example, see this video by Andreas Spiess that compares a couple of types.

References

Hardware

It got these capacitive ones from Aliexpress.

I've connected it up as follows:

  • probe GND (black) to Wemos D1 mini pin D5
  • probe VCC (red) to Wemos D1 mini pin D0
  • probe AOUT (yellow) to Wemos D1 mini pin A0

This way, all connections on the Wemos D1 are right next to each other and the wire with the 3-pin connector can simply be plugged into the Wemos D1 mini without having to modify the cable.

The software puts a low level on pin D5 (to emulate GND) and a high level on pin D0 (to emulate VCC). The idea is that the operating current of the probe is low enough for this trick to work.

I put heatshrink wrapping around the top part of the probe, to protect the electronics from moisture.

Software

See my github repository.

The software takes a measurement at a regular interval and sends it over MQTT.