CrawlSpaceSensor - Revision history

Bertrik Sikken: /* Hardware */

2022-04-04T16:03:37Z

Hardware

← Older revision		Revision as of 16:03, 4 April 2022
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	Using a cover glass on top of the sensor makes things more complicated, so I plan to not use a cover glass.		Using a cover glass on top of the sensor makes things more complicated, so I plan to not use a cover glass.

			=== Materials ===
			* A ping-pong ball, used as a target to reflect the laser off of, typically has a diameter of 40 mm.
			* PVC tube 50mm, with the thickness of the tube about 3mm, should have 44 mm inside diameter, e.g. https://www.gamma.nl/assortiment/martens-rio-buis-grijs-50-mm-1-meter/p/B258777
			* PVC end cap 50mm, to mount the electronics on, e.g. https://www.gamma.nl/assortiment/martens-eindstop-grijs-met-schroefdeksel-50-mm/p/B019216

	=== Software ===		=== Software ===

2022-04-04T16:02:20Z

Theory

← Older revision		Revision as of 16:02, 4 April 2022
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	A reflection coefficient of 2% is quite low, and indeed experimentation showed difficulties determining range towards the fluid level in a glass of water.		A reflection coefficient of 2% is quite low, and indeed experimentation showed difficulties determining range towards the fluid level in a glass of water.
	Perhaps a practical way is to measure distance to some floating object instead, like a piece of white polystyrene foam, or a white ping-pong ball.		Perhaps a practical way is to measure distance to some floating object instead, like a piece of white polystyrene foam, or a white ping-pong ball.

	~~Materials:~~
	* A ping-pong ball, typically has a diameter of 40 mm.
	* PVC tube 50mm, with the thickness of the tube about 3mm, results in 44 mm inside diameter, e.g. https://www.gamma.nl/assortiment/martens-rio-buis-grijs-50-mm-1-meter/p/B258777
	* PVC end cap 50mm, to mount the electronics on, e.g. https://www.gamma.nl/assortiment/martens-eindstop-grijs-met-schroefdeksel-50-mm/p/B019216

	=== Calibration ===		=== Calibration ===

2022-04-04T16:02:04Z

Reflection

← Older revision		Revision as of 16:02, 4 April 2022
Line 35:		Line 35:
	Materials:		Materials:
	* A ping-pong ball, typically has a diameter of 40 mm.		* A ping-pong ball, typically has a diameter of 40 mm.
	* PVC tube 50mm, with the thickness of the tube about 3mm, results in 44 mm inside diameter, e.g.		* PVC tube 50mm, with the thickness of the tube about 3mm, results in 44 mm inside diameter, e.g. https://www.gamma.nl/assortiment/martens-rio-buis-grijs-50-mm-1-meter/p/B258777
	https://www.gamma.nl/assortiment/martens-rio-buis-grijs-50-mm-1-meter/p/B258777
	* PVC end cap 50mm, to mount the electronics on, e.g. https://www.gamma.nl/assortiment/martens-eindstop-grijs-met-schroefdeksel-50-mm/p/B019216		* PVC end cap 50mm, to mount the electronics on, e.g. https://www.gamma.nl/assortiment/martens-eindstop-grijs-met-schroefdeksel-50-mm/p/B019216

2022-04-04T16:01:52Z

Reflection

← Older revision		Revision as of 16:01, 4 April 2022
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	* for air-water, we have n1=1.00 and n2=1.33, the reflection coefficient is 2%.		* for air-water, we have n1=1.00 and n2=1.33, the reflection coefficient is 2%.

	A reflection coefficient of 2% is quite low, and indeed ~~some~~ experimentation showed difficulties determining range towards the fluid level in a glass of water.		A reflection coefficient of 2% is quite low, and indeed experimentation showed difficulties determining range towards the fluid level in a glass of water.
	Perhaps a practical way is to measure distance to some floating object instead, like a piece of white polystyrene foam, or a ping-pong ball.		Perhaps a practical way is to measure distance to some floating object instead, like a piece of white polystyrene foam, or a white ping-pong ball.

			Materials:
			* A ping-pong ball, typically has a diameter of 40 mm.
			* PVC tube 50mm, with the thickness of the tube about 3mm, results in 44 mm inside diameter, e.g.
			https://www.gamma.nl/assortiment/martens-rio-buis-grijs-50-mm-1-meter/p/B258777
			* PVC end cap 50mm, to mount the electronics on, e.g. https://www.gamma.nl/assortiment/martens-eindstop-grijs-met-schroefdeksel-50-mm/p/B019216

	=== Calibration ===		=== Calibration ===

2018-05-13T20:07:02Z

← Older revision		Revision as of 20:07, 13 May 2018
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	\|Picture=CrawlSpaceSensor.jpg		\|Picture=CrawlSpaceSensor.jpg
	\|Omschrijving=Water level sensor inside crawl space		\|Omschrijving=Water level sensor inside crawl space
	\|Status=~~In progress~~		\|Status=Completed
	\|Contact=bertrik		\|Contact=bertrik
	}}		}}
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	See [http://graphana.vanheusden.com/dashboard/db/fvh-shared the bottom graph on this page] for live data from a water level meter in the crawl space.		See [http://graphana.vanheusden.com/dashboard/db/fvh-shared the bottom graph on this page] for live data from a water level meter in the crawl space.

	~~TODO~~:		Status:
	* think about the ~~measurement mechanics: direct measurement~~ of ~~level, or floaty thing (e.g~~. ~~ping-pong ball) in a tube~~		we tried it, didn't work really well on raw water surface, probably we need to bounce the laser of something that floats in the water.

	== Theory ==		== Theory ==

2017-11-29T09:28:33Z

Data format

← Older revision		Revision as of 09:28, 29 November 2017
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	The plan is to encode the measurement data in JSON and post it as text on a MQTT topic.		The plan is to encode the measurement data in JSON and post it as text on a MQTT topic.

	~~Exampled~~ of proposed data format:		Example of proposed data format:
	<pre>		<pre>
	{		{

2017-10-30T16:38:22Z

← Older revision		Revision as of 16:38, 30 October 2017
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	Measurement data is uploaded once an hour over WiFi to an MQTT server.		Measurement data is uploaded once an hour over WiFi to an MQTT server.

	~~Since there is likely no mains power easily available~~ in a crawl space~~, it is battery operated~~.		See [http://graphana.vanheusden.com/dashboard/db/fvh-shared the bottom graph on this page] for live data from a water level meter in the crawl space.

	TODO:		TODO:
	* think about the measurement mechanics: direct measurement of level, or floaty thing (ball) in a tube		* think about the measurement mechanics: direct measurement of level, or floaty thing (e.g. ping-pong ball) in a tube

	== Theory ==		== Theory ==

2017-05-22T09:53:11Z

Update omschrijving

← Older revision		Revision as of 09:53, 22 May 2017
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	\|Name=CrawlSpaceSensor		\|Name=CrawlSpaceSensor
	\|Picture=CrawlSpaceSensor.jpg		\|Picture=CrawlSpaceSensor.jpg
	\|Omschrijving=~~Sensor~~ inside crawl space		\|Omschrijving=Water level sensor inside crawl space
	\|Status=In progress		\|Status=In progress
	\|Contact=bertrik		\|Contact=bertrik

2017-05-22T09:52:05Z

Update picture link

← Older revision		Revision as of 09:52, 22 May 2017
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	{{Project		{{Project
	\|Name=CrawlSpaceSensor		\|Name=CrawlSpaceSensor
	\|Picture=~~whyunoimage~~.~~png~~		\|Picture=CrawlSpaceSensor.jpg
	\|Omschrijving=Sensor inside crawl space		\|Omschrijving=Sensor inside crawl space
	\|Status=In progress		\|Status=In progress

2017-05-09T07:57:48Z

In progress

← Older revision		Revision as of 07:57, 9 May 2017
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	\|Picture=whyunoimage.png		\|Picture=whyunoimage.png
	\|Omschrijving=Sensor inside crawl space		\|Omschrijving=Sensor inside crawl space
	\|Status=~~Initializing~~		\|Status=In progress
	\|Contact=bertrik		\|Contact=bertrik
	}}		}}