Ping Ultrasonic distance sensor life expectancy

mckaycr

I have a project I'm working on called Sonic Dip Stick that measures the amount of oil I have in my oil tank. Right now I ping the oil every 24 hours, but I was wondering what is the recommended time between pings over an indefinite time before I wear the device out?

Obviously I don't need to check the oil level more than a couple times a day for a decent oil usage statistic, however I have come up with a new requirement.

I'd like to place a display outside the house (the tank is inside) where the supplier fills the tank. I'd like to be able to detect a rapid change in oil level so that it can be presented on the display. The supplier will see an accurate oil level as he is filling. But I also don't want to over work the sensor by taking pointless measurements when no activity is occurring within the tank. Also, I'd like to not require the use of some other sensor for detecting motion within the tank or anything like that.

So again, bottom line, how frequent can I take measurements for an indefinite period without putting undue stress on the sensor?

erco

I would be more concerned about degradation from environmental effects inside the tank than usage wear & tear. Is this fuel oil?

erco

BTW I'd add a pushbutton switch on or near your outside display for the refiller to press. Maybe that button starts a routine to send ONE PING ONLY every 30 seconds and update the display, maybe for 10 minutes total then stops.

GordonMcComb

Does the sensor go INSIDE the tank?! If so, you need a waterproof housing, ideally a housing resistant to VOCs. I'm not even sure I'd want to put anything electrical inside the tank in any case. How long is the liquid level? Maybe there's a way to place a series of IR detectors on the tube to read the value.

In any case, a few dozen pings a day for the life of your house shouldn't be too much to expect. But like Erco says, it's not exactly a healthy environment inside the tank.

Publison

Better to use eTape. That is what it is made for.

https://www.parallax.com/search?search_api_views_fulltext=eTape

mckaycr

erco wrote: »

I would be more concerned about degradation from environmental effects inside the tank than usage wear & tear. Is this fuel oil?

The sensor isn't inside the tank, but your concern is understood. I have taken every precaution to eliminate any contact between the oil and the sensor.

erco wrote: »

BTW I'd add a pushbutton switch on or near your outside display for the refiller to press. Maybe that button starts a routine to send ONE PING ONLY every 30 seconds and update the display, maybe for 10 minutes total then stops.

Thanks, this is a good idea.

GordonMcComb wrote: »

Does the sensor go INSIDE the tank?! If so, you need a waterproof housing, ideally a housing resistant to VOCs. I'm not even sure I'd want to put anything electrical inside the tank in any case. How long is the liquid level? Maybe there's a way to place a series of IR detectors on the tube to read the value.
In any case, a few dozen pings a day for the life of your house shouldn't be too much to expect. But like Erco says, it's not exactly a healthy environment inside the tank.

The original float threaded into a 2 inch hole on the top of the tank. I simply took that off, found a 2 inch threaded PVC socket and screwed that into place, putting the sensor inside the PVC pointed down at the oil. It is sealed so that even any splash back wouldn't hit the circuit board, but only (worst case) the two round bits that send and receive the signal

Publison wrote: »

Better to use eTape. That is what it is made for.
https://www.parallax.com/search?search_api_views_fulltext=eTape

Interesting, I have never seen this before. I like this better than the sonar module, I'll need to see about getting 44 inches of etape. I like the idea of installing it inside a 1 inch PVC pipe to keep it vertical. Thanks for pointing this product out to me. I will do some serious research into this.

xanadu

Does the oil delivery truck meter out x amount of gallons?

If so, and your display shows remaining gallons, it should be easy to pump the difference. I feel like the fumes are going to be more of a wear-and-tear issue than polling it too much, but that's a guess.

GordonMcComb

mckaycr wrote: »

The original float threaded into a 2 inch hole on the top of the tank. I simply took that off, found a 2 inch threaded PVC socket and screwed that into place, putting the sensor inside the PVC pointed down at the oil. It is sealed so that even any splash back wouldn't hit the circuit board, but only (worst case) the two round bits that send and receive the signal

The issue is that fuel oil is like any distillate and inside the tank there are fumes from the volatile organic compounds of the liquid. These fumes A ) can corrode or deteriorate materials not suitably protected and B ) give rise to fire danger in the case of a short. Most fuel oils have a low flash point.

You might be able to pull it off if you drilled two holes in the cap and poked the sender and receiver transducers through it, then sealing if off so that no part of the circuit board is exposed to the fumes. This doesn't mean there are no concerns of a short in the transducers. I don't know the design of those, but to make the pinging worthwhile, there needs to be some amount of current to the sender element. The eTape idea seems a lot safer to me.