dumb sensor questions

my assumption has been that my antiquated NA/US water and gas meters would not support sensors - which means that so far I've been too lazy to even go check on the vendor/model numbers to verify.

but this morning I was inspired to go look, and the gas is Actaris Metris, and the water is Neptune with a 2-wire Schlumberger display. need to find out more, but this is slightly promising.

(a few cities in California have even been giving away free wireless internet via all new smart meter upgrades! lucky. don't think my town will be seeing that anytime soon)

the next step (the true dumb question) is - what is a reasonable maximum length for PWM? (obviously that depends on frequency, voltage, etc - signal too weak if wire too long, picking up radio interference or crosstalk if wire too long, etc)

I've tried to do some searching, but all I really found so far is that the "official" sensor cables are 2m. I think I'm not alone in this, 6' is not going to reach the meters in more than a few households.

for one thing, the local building code requires gas bulkhead, which is often where the meter also goes for convenience, to be a certain distance from electrical mains - so our gas meter is 8 feet from the mains, and also outside the house, while of course the flukso lives inside the house.

water meter is inside the house, but something like 25' or more from the electrics panel.

another thing that changes the whole nature of this question, at some point soon I'll be smiling when a shiny flukso v2b arrives - the 868mhz radio may be very useful getting around distances. at which point I can hack together my own rfm12b sensors of many crazy kinds*. (the outside gas meter could still be a problem though, our house is wrapped in foil, literally - all the insulation inside every single wall is metal-coated - even entirely below the foundation!)

*can flukso monitor the level of seed in the bird feeder? tell me the refrigerator temperature? inform me that the neighbors need to mow their lawn? rig a jeenode into a Watt's-Up meter and tell me about PV DC? sure, why not!!!

icarus75's picture

Love the enthusiasm for the new radio link! Not sure though what you mean by PWM: the FLS02's are reed switches, with very low 'frequency'. You can extend this to 10's of meters without any worry.

tintar's picture

thanks Bart, as always, for the patient and very helpful reply - the smart meter side is still all pretty new to me, as I've no doubt mentioned many times: the meters I grew up with were practically stone-age.

with lengths like that, I should not have any problem reaching the meters. well, maybe still the water meter ;-) we'll see!