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Rain sensor


martin_h

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It's important to realise that this is a very small device: the sensor area is about the size of my thumb. Plus, you still have a significant amount of DIY to, errr ..... do yourself. Added to which, there's the price of a power supply.

The description carries an implied admission that the sensor may not detect direct rainfall :huh: if your rain is too "pure".

So although I've not used one, it doesn't sound like a device I'd be willing to trust to keep ££££'s of equipment dry.

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It's important to realise that this is a very small device: the sensor area is about the size of my thumb. Plus, you still have a significant amount of DIY to, errr ..... do yourself. Added to which, there's the price of a power supply.

The description carries an implied admission that the sensor may not detect direct rainfall :huh: if your rain is too "pure".

So although I've not used one, it doesn't sound like a device I'd be willing to trust to keep ££££'s of equipment dry.

And also minimal false positives in the sensor, once they are wet, how can they determine whether that is old rain or new rain :)

Kemo's product page is here http://www.kemo-electronic.de/en/House/Garden/M152-Rain-Sensor-12-V-DC.php

Data sheet here http://www.kemo-electronic.de/datasheets/m152.pdf

You probably don't want to have these placed near a roof where water can drip down onto the sensors thus sending more false positives or shield them from the actual rain (probably placing them at an angle will help the old rain run off the sensor :) ).

Perhaps multiple smaller cheaper sensors spaced about and a voting system between them will reduce false positives. Would be a fun Arduino project or something (or this $9 CHIP computer coming out).

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And also minimal false positives in the sensor, once they are wet, how can they determine whether that is old rain or new rain :)

Most have a small heater that is constantly on. This slowly evaporates rain that accumulates on the sensor.  It's also a good idea to mount that sensor at a slight angle to aid rain drops running off.

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So say for example, if I bunch together an odd number of cheap sensors (odd number makes voting easier, no tie-breaker situations), say three, that should reduce false positives to near zero, wouldn't it? Assuming they are placed at differing angles (slight not huge angle) and spaced out far apart. Three should be enough to get very reliable readings.

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So say for example, if I bunch together an odd number of cheap sensors (odd number makes voting easier, no tie-breaker situations), say three, that should reduce false positives to near zero, wouldn't it? Assuming they are placed at differing angles (slight not huge angle) and spaced out far apart. Three should be enough to get very reliable readings.

Assuming that the reason for false positives are glitches in individual sensors or their electronics and not a design flaw/feature in the design of the sensors, then this would seem a logical way of reducing false positives.

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Assuming that the reason for false positives are glitches in individual sensors or their electronics and not a design flaw/feature in the design of the sensors, then this would seem a logical way of reducing false positives.

And each sensor being different brands, batch, or models.

How well do these work with HAIL?

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