Have been playing with some DS18B20 sensors on a freetronics etherten board, currently have two working over cat5 cable, both runs probably 10-15meters, but if I add a third it stops working.
I really want to set it up with 10-12 temperature sensors in total in a star setup mainly because the cat5 cables are all existing to each room.
Just wondering if anyone has done something similar, have done some searching and haven't come up with many examples. Just wondering if I was to do something like this, do you leave the power/gnd connected and just switch (using a relay) the data ?!
matbor:
Have been playing with some DS18B20 sensors on a freetronics etherten board, currently have two working over cat5 cable, both runs probably 10-15meters, but if I add a third it stops working.
I really want to set it up with 10-12 temperature sensors in total in a star setup mainly because the cat5 cables are all existing to each room.
Just wondering if anyone has done something similar, have done some searching and haven't come up with many examples. Just wondering if I was to do something like this, do you leave the power/gnd connected and just switch (using a relay) the data ?!
Thx
Matt.
Making it all too hard for yourself !
Keep it simple with the sensors
I use a mix of cat5/6 everywhere for my sensors and they work fine - however based on trial and error i find it far more reliable to have a single sensor per pin - in your case - get another Arduino (a mega for instance) and communicate between the two using i2c
If you want to persist then look at the resistor values you are using (you are not trying to do this parasitically powered are you ?)
Ah why didn't I think of that! Awesome idea, now to work out how to change the code a little
Update: changed the resistor to a 2k2, now I have 4x runs of 10/15meters and it is working nicely and with the suggestion above I will have my temp sensor network working nicely.
Ummm did I miss something, you will need 12 Arduinos if you use I2C, or maybe 6 if you have 2 sensors on each. And anyway I2C is not good for these distances.
runs of 10/15meters
Still a factor of 10 from the 150m you need.
Those sorts of distances are normally the domain of RS-485/422.
Graynomad:
Ummm did I miss something, you will need 12 Arduinos if you use I2C, or maybe 6 if you have 2 sensors on each. And anyway I2C is not good for these distances.
runs of 10/15meters
Still a factor of 10 from the 150m you need.
Those sorts of distances are normally the domain of RS-485/422.
Rob
C'mon Rob - you are losing it !!
I meant a 2nd Arduino - connected to the first arduino with i2c. The 2nd Arduino has an individual OneWire run per pin (rather than daisy Chaining them) (so for a Mega thats a lot of Temp Sensors) !!
I assume as he had CAT5 to each room then all of the points would come back to terminate in a single punchdown - therefore if he puts an Arduino there he can individually address each piece of CAT5 and declare as many OneWire buses as he needs.
Getting there, I've swapped to general lantana and long-grass clearing lately, steep rocky ground with grass as tall as me in places and lantana too thick to get through. We've done maybe 8-10 acres with I guess another 4-5 to go before I reckon we're done. No point doing the entire block. Then I'll clear the logs and finally get back to my track making.
The brushcutters are getting a workout that's for sure.
Graynomad:
Getting there, I've swapped to general lantana and long-grass clearing lately, steep rocky ground with grass as tall as me in places and lantana too thick to get through. We've done maybe 8-10 acres with I guess another 4-5 to go before I reckon we're done. No point doing the entire block. Then I'll clear the logs and finally get back to my track making.
The brushcutters are getting a workout that's for sure.
Rob
Now i have lost all respect - in my mind i had a vision of you looking like Grizzly Adams with a machete or panga in each hand cutting a swathe through the jungle and emerging to slam down a solo !! Now you tell me you are lazing back doing it with a brush cutter !!
Anyone shredding up lantana gets a tip of the hat from me...that's tough going. Stir in the secret exotic location near Bundy and it's got win written all over it imo
Graynomad:
...lantana...
Have I got my cred back now
Lantana? Where I'm from that's a purdy flower. We even put them on display.
Try clearing these (notice the picture on the left side; in case it isn't clear this will help) while keeping your eyes out for these. They've been known to do this.
Wow they do look nasty. I don't envy you that job either.
The problem with Lantana here is it loves our climate and has no natural enemies. We recently cleared it from a corner of a paddock where it had got up in the canopies of the gum trees as well as choking out everything with an impenetrable barrier down low. Awful stuff.
My god - whichever idiot wrote that article on Wikipedia should be taken to school about natural water and fertility cycles - we have the same types of idiots here in government who have for a long time paid our farmers to rip out willow trees alongside our natural water ways.
strykeroz:
Wow they do look nasty. I don't envy you that job either.
The problem with Lantana here is it loves our climate and has no natural enemies. We recently cleared it from a corner of a paddock where it had got up in the canopies of the gum trees as well as choking out everything with an impenetrable barrier down low. Awful stuff.
Geoff
Geoff, you should head over to the natural sequence farming website and have a talk to people there about Lantana and how you can use it to go effect on your property
