1-wire counter

cdpuk

Member
I received my counter board from hobby boards yesterday (thanks Eric). It appears the device is very sensitive so it's hard to get it count individual switch closures. Even touching a wire from input A to +5V produces several counts, when I only want one.

Is there a way to prevent this happening? The idea was to register counts from a rain gauge I'm making, currently using a magnetic switch. Is there something added to the rain gauges sold to do this?

Thanks
-Chris
 

ericvic

Active Member
Chris,

The Rain Gauge we sell only has a redd switch and a magnet. The DS2423 chip has internal debounce circuitry but by manually touching the terminals together to cause it to count it is easy to get multiple counts but when using it with a reed switch or something similar it doesn't seem to false count.

Hope that helps.

Eric
 

BraveSirRobbin

Moderator
cdpuk said:
The idea was to register counts from a rain gauge I'm making, currently using a magnetic switch.
Chris;

Off topic but I (and I'm sure other forum members) would love to see pictures and details of this project!

Can you possibly provide some of these details (pics would be great while you are building it)?

Thanks,

BSR
 

cdpuk

Member
OK thanks Eric. I've not actually tried the switch with it yet so maybe I should have done that before posting here :p

I do plan on writing a full guide once it's complete. I wasn't really sure whether it'd work or not. I have a large, but good quality switch, so balancing the buckets was a pain. There's a few pictures of some of the parts here, bad camera for those images unfortunately:

http://gallery.cdpuk.net/v/cdpuk/

The actualy bucket came from a thin sheet of brass, cut, bent and filed into shape (Looks a lot better now than in the picture). You can see the perspex base (cover not shown) with holes in the sides for the bearings. I've managed to get it to tip so with a funnel 7" in diameter it'd get a resolution of 0.1mm.

Looks good so far! Just need to get the counter hooked up to the switch and find a suitable funnel.

-Chris
 

cdpuk

Member
Just connected it up straight to the switch, worked perfectly!

As I said before, just need to complete the assembly.

Shame I don't have it outside yet, we're having a drought at the moment in the south of England, but this week it's actually raining!

-Chris
 

cdpuk

Member
Everything seems fine, until I connect up the switch with some extra telephone wire then the counter goes mad again - counting 3000-4000 per minute. I planned on mounting the counter board in the same place as the temp/humidity sensor, then running another wire (about 4-5m long) to the switch in the rain gauge. The switch is certainly open when this is happening, other meters agree that there is no connection.

Is there some property of the telephone wire causing this? The switch came with about 3m of wire attached (works fine when going directly into the counter), but just 30cm of telephone wire added on stops it working. Would CAT5 be any better? Or should I just try and mount the counter inside the casing of the rain gauge?

Thanks
-Chris
 

ericvic

Active Member
Chris,

I think the best bet is to mount the counter inside the rain gauge (shielded from moisture of course). The counters have high impedance inputs so it could be picking up interference on the telephone wire causing the false counts.

Eric
 

cdpuk

Member
Alright then, it shouldn't be too hard to do that. I don't think there's enough space inside the enclosure now, but I'm sure I can find a box I can seal and attach to the side.

Thanks
-Chris
 
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