# modify bucket to 0.1mm

Hi folks

I already have 0.25mm and now i want to go to 0.1mm please
I am ready to go out the door to buy the funnel/bowl but i am
not sure what diameter i need…

Also what offset would i need t0 add for this size please?

UPDATE:

Derek has kindly made a calculator in MS Excel and can be found in this post further in this thread
Thank you Derek

Niko point me to this tip conversion maths thing, should start here
http://www.realweatherstation.com/rgcalc/

This kind of thing come up often enough, wouldn’t it be nice if someone wrote a little online calculator? It would take someone better with the math than I am.

• Jim

I even tried doing a search for my other posts, can i hell as find it… #-o
Although that didn’t actually give me the answer as i settled for the .25 in the end

but yeah a calculator would be a great idea

It is very easy:

original section / new section = resolution

So: new section = orignal section / desired resolution

An example for your particular case:

• Desired resolution = 0.1 mm

• Original Oregon section = 78.5379 cm2

• New section required= 78.5379 / 0.1 = 785.379 cm2

• Section = PI * square radius; Radius = sq root (section / PI)

So you need a funnel of 15.81 cm radius. Or 31.62 cm diameter.

Edit: just a note on this. Take into account that you are letting so much more water inside, so the tipping mechanism can be easily overflown. The accuracy you’re looking for may become a big error.

Easy, yeah i can see that… :? lol

I do not understand the majority of that, maths is far from my strong point
But i thank you for the answer

Actually, i think i do sort of, in my cause all i needed to do was to move the decimal

so am i right in thinking the offset would be 0.1?

I don’t know exactly what you have done. This is what you need:

• Control Panel
• Offsets & initial rain
• Rain offset
• Modified rain gauge new tip (mm)

1.- Calculate the new section: divide funnel diameter by 2. Square it (multiplying by itself). Multiply by 3.1415

2.- Divide the old section (original Oregon) by the new section.

3.- The result is what you have to enter on WD.

Looks like i went the wrong way, it was more of a guess… #-o

So, with the sums done, i make the offset at 10. does that sound more realistic?

No, it is not an offset. It is a new tip volume.

Let me know the inner diameter of your funnel, I’ll do the math for you.

Just my personal opinion but I think that’s an unreasonable decrease in tip size. I wouldn’t be trying to push that amount of water through that coffee mug sized OS rain gauge.

Sorry Breitling it was the tip size i was on about, its cause its in the rain offsets is why
i kept calling it the offset :oops:

The internal Diameter is now exactly 31cm thanks Breitling…
i cut the darn thing down too much, so much for the 0.1mm, it cant be too far off though

I just want to give it a try Niko, see how it goes, if its too much then i will just remove it

It looks a bit ott i mist admit cause each stage i have made it bigger i just kept the older
one attached so it had the area for the new one to fit into, to its a 3 stage tower now lol

I also had to use a biggish flower container, finding a funnel was proving difficult for the size
wanted, so i went for something much bigger and cut it down…I aint attached it to the bucket
yet so no pics at present sorry, to be honest i dont really want to show it off either :oops:

hi Simon

0.1 is going to give you quite a few problems , as soon as you get moderate rain it will overwhelm the sensor

and give you incorrect rain readings

the lowest I have managed to get 0.25 tipping so far this is give me good results I would have fought there was a standard for the minimum tipping of most rain gauges Davies 0.2

I will be interested to see how you go on with this please send me some data back when you have some heavy rain
I would also put out a traditional manual rain gauge so you can compare results

mick

Its up and waiting for the rain now lol

If it does cause any issues then i will just remove it again, its was stuck down with
hot glue so thinners will easily dissolve the glue, dont care about the addons if they
melt a little i can just sand them down

I will certainly let you know how it goes, theres a manual weather station in Lidl later this week
could be now actually, i cant remember and i will get that to compare with

I thought davis was 0.1mm? oh well lol but i did read on here somewhere that someone did modify
to 0.1mm and it was running ok, just cant remember where i read it now…

I dont think its gonna be quite 0.1mm anyway as i cut it down too much #-o

Just need to tip size and im good to go

Good stuff Bashy, let us know how you get on (maybe a test pour with a jug?)

You really are the king of diy!

Thanks lol, you aint seen the image yet, attached below :oops:
A test pour never works out, i always end up doing too fast
But i will report the findings thats for sure…

Please dont laff, at least the top looks pretty :lol:

Looking at it i can see it getting blown off either Friday or Sunday :? :roll:

Maybe better math, but certainly not better php :oops:

That calulator’s no good for thoughs of us with La Crosse raingauges, they’re square!! :lol:

Oh, I haven’t seen that model, they used to be rectangular :lol:

HI Niko, thanks for the link but witt me being as thick as i am
i aint got a clue what goes in the old tip and new tip :oops:

It’s the weather here, it alters their shape. :oops:

Oh, do you want this calculation?