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 | 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 | |
|---|---|
| |
| 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.