Cheap(ish) rain sensor?

[NJ Roadmap]

I'm looking for one for a little garden project I'm doing but don't want to spend more than about £20 excl. postage. Has anyone used any of these?

 

[NJ Roadmap]

I am looking for an ready-made one rather than a home-made tipping bucket solution with a reed switch as has been discussed in the past.

 

[Roff]

Do you want to simply sense rain, or do you want to measure it?

 

[NJ Roadmap]

Just sense it.

 

[Nigel Goodwin]

The usual solution is just a PCB with interleaving 'fingers', the water makes a conductive path across them - veroboard can be used as well, just link alternate tracks.

 

[NJ Roadmap]

I had a look at the link about the PCB-based sensor posted during a previous discussion, it seems simple enough but I was wondering what kind of reliability issues would be associated with this due to water stagnation?

For reference, the link is: https://www.aaroncake.net/circuits/raindet.htm

 

[Roff]

I had a look at the link about the PCB-based sensor posted during a previous discussion, it seems simple enough but I was wondering what kind of reliability issues would be associated with this due to water stagnation?

For reference, the link is: https://www.aaroncake.net/circuits/raindet.htm

Stagnation? Put it where the water will evaporate.

 

[Nigel Goodwin]

Stagnation? Put it where the water will evaporate.

And gold plate the PCB, to avoid corrosion!.

 

[Rolf]

I had a look at the link about the PCB-based sensor posted during a previous discussion, it seems simple enough but I was wondering what kind of reliability issues would be associated with this due to water stagnation?

For reference, the link is: https://www.aaroncake.net/circuits/raindet.htm

I think that if you tinned the PCB traces and tilted the board slightly so that the rain would drain off fairly rapidly, it would last for a long time. You might have to put some spikes on it to keep the birds off.

 

[sriram karhik]

hi friend

hi,
i am a new user to this .i am doing my engg. in india and i am in a situation to some project on electrical or electronics.if you have any ideas regarding these(headings,circuitsetc...,) please inform me as soon as possible

 

[ThermalRunaway]

I've often wondered how the rain sensors on cars work. Some models can sense if it's raining, and adjust the repetativeness of the windscreen wipers to suit. Some better models go even further and seem to be able to tell when the windscreen will have sufficient rain on it to warrant a windscreen swipe! I am impressed by how quickly they respond to changes in the heavyness of the rainfall.

I like little gimmicks like that.

Brian

 

[NJ Roadmap]

hi,
i am a new user to this .i am doing my engg. in india and i am in a situation to some project on electrical or electronics.if you have any ideas regarding these(headings,circuitsetc...,) please inform me as soon as possible

Stop poisoning my thread and this forum. Are you a bot?!

 

[Roff]

Stop poisoning my thread and this forum. Are you a bot?!

I'm guessing he's a noob to forums, ran across this thread on a search engine, and didn't know the protocol for starting a new thread.

 

[3v0]

Some ideas.

I would tilt it as mentioned to get the water to run off.

Use a MPU to measure the resistance. That way you could monitor the dry resistance as it changed (cruded up) over time. Use the same info to inform of the need to clean the sensor plate. Determine that a bird has gifted it etc.

Use a small fan or heat the plate to increase response time.

 

[druidmerlin]

A modification to tilting bucket and reed switch --

Use a badminton raquet or similar lightweight frame with a cotton cloth stretched across --- works well in mist application in Leylandii propogation in greenhouses.

Old Brit Maidenhead UK

 

[spuffock]

Put a capacitor in series with it. A PIC will give you a nice AC to drive it.Otherwise it will corrode,gold or no gold.

 

[gramo]

Put a capacitor in series with it. A PIC will give you a nice AC to drive it.Otherwise it will corrode,gold or no gold.

What value capacitor would you use, and what do you mean by AC?

 

[Hero999]

AC as in square-wave.

The value of capacitance will depend on the frequency.

 

[gramo]

AC as in square-wave.

The value of capacitance will depend on the frequency.

Sorry to delve further into this, just interested of making something similar, but haven’t thought down this road yet.

Why does this stop the corrosion of the tracks, and what frequency/capacitance values would you recommend?

 

[Hero999]

It probably won't stop corrosion completely but it might slow it down, at least by 50%.

With AC both tracks will corrode equally, unlike DC which will cause the anode only to corrode.

I don't know what frequency to use but higher is probab;y better and the capacitance doesn't matter providing its impedance is low compated to the water.