Looking for some help on an idea, I have no real experience with programming, just a copy and past so far.
A bit of back ground, I live in rural Indiana so in order to heat our home we use a Liquid Propane Tank. It usually takes about a week for the fuel to get delivered. Recently I spaced on checking the fuel level on the tank and ran out. So instead of waiting until I get in the shower only to find cold water, I would like to build an arduino that measures the propane percentage (or pressure) the tank has and once below a certain threshold, I would like for it to send an SMS to remind me to call for a refill.
What are recommended SMS systems that one would use
What type of sensor should be used for the Propane Tank
So from what I gather for the Google propane weighs about 4.2 pound per gallon. I like your idea for the cable system (sits next to the house).If i could gather the weight of the tank I could set up a scale and BINGO I'm there.
I was hoping to make this much more difficult via a sweet arduino system, not giving up!
Once I get a scale and more information, I'll be back.
Unfortunately the tank is owned by the Gas company, I don't think I am allowed to modify it. Actually now that i think about it I may have to ask if I can even put a scale under it.
My original idea, was to make modifications inside the house measuring pressure, but as mentioned, there is not a reliable way of measuring other than an internal tank gauge or simply by weight.
You can't tell the tank's level by reading pressure, because propane exists in both gaseous and liquid form inside the tank. Pressure is essentially constant on the output line as liquid vaporizes inside the tank to replace the gas leaving. A pressure gauge wouldn't be useful (or you'd think they'd probably include them on tanks, right?)
Compressed air tanks, for example, do not liquefy the air. No phase change means a pressure gauge is actually correlated to level of fill, as the pressure does increase and decrease with level.
Weight is one way to tell, but I'm assuming you are dealing with one of those big household tanks, so that's going to need a specialized load sensor in that weight range. You'd just have to stick it under one of the supports, depending on how it's mounted.
Have you asked the propane and propane accessories company on how you would determine the fill level in your tank? They'd probably just tell you to do the hot water trick (pour hot water down the side of the tank, feel where it's cooler) but maybe they have some fancy device that might give you an idea.
Come to think of it, a flow meter might just be the ticket. Measure how much volume of gas is coming in from a full tank to empty, and extrapolate from there. Sounds stupid simple after I typed all that up there.
Bear in mind there may well be electrical zoned areas around the tank and your device may have to be i intrinsically safe ( only achieved by certication).
hammy:
Bear in mind there may well be electrical zoned areas around the tank and your device may have to be i intrinsically safe ( only achieved by certication).
Good catch. I ran into this last spring when our A.C. was replaced. New codes, overriding those in effect when the house was built, require ten foot minimum separation between propane and A.C. outside unit, or any other ignition source.
