SoilHumiditySensor - Revision history

Bertrik Sikken at 20:03, 27 June 2019

2019-06-27T20:03:23Z

← Older revision		Revision as of 20:03, 27 June 2019
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	== Introduction ==		== Introduction ==
			This project is a simple soil humidity sensor that publishes the humidity over MQTT to the internet.

	A number of types of soil humidity sensors exist.		A number of types of soil humidity sensors exist.
	Many have the problem that the electrodes corrode over time because of electrolytic effect.		Many have the problem that the electrodes corrode over time because of electrolytic effect.

Bertrik Sikken: /* Software */

2019-05-21T16:40:54Z

Software

← Older revision		Revision as of 16:40, 21 May 2019
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	The software takes a measurement at a regular interval and sends it over MQTT.		The software takes a measurement at a regular interval and sends it over MQTT.

			The measurement value is a 'humidity percentage', with 0 representing a completely dry environment and 100 a completely wet environment.
			I don't know the optimal value yet, but typically my plants are at about 60%.

Bertrik Sikken at 16:38, 21 May 2019

2019-05-21T16:38:17Z

← Older revision		Revision as of 16:38, 21 May 2019
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	A number of types of soil humidity sensors exist.		A number of types of soil humidity sensors exist.
	Many have the problem that the electrodes corrode over time because of electrolytic effect.		Many have the problem that the electrodes corrode over time because of electrolytic effect.
			The one used in this project uses capacitance to measure soil humidity avoiding direct electrical contact between the electrode and the soil.

	== References ==		== References ==
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	== Hardware ==		== Hardware ==
	I got [https://nl.aliexpress.com/item/32882371718.html these capacitive ones] from Aliexpress.		I got [https://nl.aliexpress.com/item/32882371718.html these capacitive ones] from Aliexpress.
	The electrodes themselves are covered in solder mask~~, so the soil does not touch any electrodes directly~~.		The electrodes themselves are covered in solder mask.
	I put heatshrink wrapping around the top part of the probe, to protect the electronics from moisture.		I put heatshrink wrapping around the top part of the probe, to protect the electronics from moisture.

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	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 havent actually measured this current.

	== Software ==		== Software ==

Bertrik Sikken at 16:33, 21 May 2019

2019-05-21T16:33:39Z

← Older revision		Revision as of 16:33, 21 May 2019
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	\|Picture=SoilHumiditySensor.png		\|Picture=SoilHumiditySensor.png
	\|Omschrijving=Investigation of soil humidity sensors		\|Omschrijving=Investigation of soil humidity sensors
	\|Status=~~In progress~~		\|Status=Completed
	\|Contact=bertrik		\|Contact=bertrik
	}}		}}
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	== Introduction ==		== Introduction ==
	A number of types of soil humidity sensors exist.		A number of types of soil humidity sensors exist.
	Many have the problem that the electrodes corrode.		Many have the problem that the electrodes corrode over time because of electrolytic effect.

	~~For example, see this [https://youtu.be/udmJyncDvw0 video by Andreas Spiess] that compares a couple~~ of ~~types.~~

	~~I got a few probes of the capacitive type, with the electrodes themselves being covered in solder mask~~.

	== References ==		== References ==
			See this [https://youtu.be/udmJyncDvw0 video by Andreas Spiess] that compares a couple of types.

	== Hardware ==		== Hardware ==
	I got [https://nl.aliexpress.com/item/32882371718.html these capacitive ones] from Aliexpress.		I got [https://nl.aliexpress.com/item/32882371718.html these capacitive ones] from Aliexpress.
			The electrodes themselves are covered in solder mask, so the soil does not touch any electrodes directly.
	I put heatshrink wrapping around the top part of the probe, to protect the electronics from moisture.		I put heatshrink wrapping around the top part of the probe, to protect the electronics from moisture.

Bertrik Sikken: /* Hardware */

2019-05-12T20:25:48Z

Hardware

← Older revision		Revision as of 20:25, 12 May 2019
Line 19:		Line 19:

	== Hardware ==		== Hardware ==
	It got [https://nl.aliexpress.com/item/32882371718.html these capacitive ones] from Aliexpress.		I got [https://nl.aliexpress.com/item/32882371718.html these capacitive ones] from Aliexpress.
			I put heatshrink wrapping around the top part of the probe, to protect the electronics from moisture.

	I've connected ~~it up~~ to a Wemos D1 mini ESP8266 board, as follows:		It's connected to a Wemos D1 mini ESP8266 board, as follows:
	* probe GND (black) to Wemos D1 mini pin D5		* probe GND (black) to Wemos D1 mini pin D5
	* probe VCC (red) to Wemos D1 mini pin D0		* probe VCC (red) to Wemos D1 mini pin D0
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	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 ==

Bertrik Sikken at 17:18, 12 May 2019

2019-05-12T17:18:00Z

← Older revision		Revision as of 17:18, 12 May 2019
Line 13:		Line 13:

	For example, see this [https://youtu.be/udmJyncDvw0 video by Andreas Spiess] that compares a couple of types.		For example, see this [https://youtu.be/udmJyncDvw0 video by Andreas Spiess] that compares a couple of types.

			I got a few probes of the capacitive type, with the electrodes themselves being covered in solder mask.

	== References ==		== References ==

Bertrik Sikken: /* Hardware */

2019-05-12T15:47:06Z

Hardware

← Older revision		Revision as of 15:47, 12 May 2019
Line 19:		Line 19:
	It got [https://nl.aliexpress.com/item/32882371718.html these capacitive ones] from Aliexpress.		It got [https://nl.aliexpress.com/item/32882371718.html these capacitive ones] from Aliexpress.

	I've connected it up as follows:		I've connected it up to a Wemos D1 mini ESP8266 board, as follows:
	* probe GND (black) to Wemos D1 mini pin D5		* probe GND (black) to Wemos D1 mini pin D5
	* probe VCC (red) to Wemos D1 mini pin D0		* probe VCC (red) to Wemos D1 mini pin D0

Bertrik Sikken: /* Hardware */

2019-05-12T15:33:00Z

Hardware

← Older revision		Revision as of 15:33, 12 May 2019
Line 24:		Line 24:
	* 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 ==

Bertrik Sikken: /* Hardware */

2019-05-12T12:50:12Z

Hardware

← Older revision		Revision as of 12:50, 12 May 2019
Line 27:		Line 27:

	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 current 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.

	== Software ==		== Software ==

Bertrik Sikken: /* Hardware */

2019-05-12T12:49:53Z

Hardware

@@ Line 18: / Line 18: @@
 == Hardware ==
 It got [https://nl.aliexpress.com/item/32882371718.html these capacitive ones] from Aliexpress.
 == Software ==