weight of gasbottle

I want to messure the weight of the gasbottles in my camper.
This means that the weight stays on the sensors. To reduce the powerconsumption I only want to switch it on when I want to check my gasbottles.
Is this possible with the HX711 and sensors?

Yes, but probably against regulations (think insurance).
I think you are not allowed to use any electrical devices/wires near, or inside the enclosure of a gas bottle.
Leo..

I’d have a look at mechanical methods - bottle hanging off a spring or on a spring ?

Or some hydraulic method , or use a professionally fitted gas meter ( and use it’s pulse output ?)

in my camper.

I would not expect strain gauge sensors to last long, with gas bottles bouncing up and down on them while driving on a rough road.

@Wawa. I don't think that the electricity will give problems. On the bottles the reducer has electrical heating and the control for automatch switching has also electrical connections. As long as there is no switching device near the bottles I don't see problems.

@jremington. I don't know how strong the sensors are, but this can be a problem.

You need to look at the regulations for gas storage on campers before YOU can decide. People are reluctant to offer advice on this sort of topic because it is seen as potentially hazardous .

For instance ... the link below mentions competency for many items - so your heater maybe ok as it was so designed, but people here are maybe not competent in these areas, and therefore reluctant to get involved ( wisely IMO) except to point out possible pitfalls/obstacles . This is a hobby site .

http://www.hse.gov.uk/foi/internalops/ocs/400-499/440_34.htm

@Hammy, I only asked if I can switch the weight sensors on and off with the weight on it. Where and how I want to use this information is my responsibility.
FYI i'm fully qualified to work on, and design gassystem.

The basic assumption in safety rules will be that gas systems will leak and thus must be externally ventilated and kept clear of any possible ignition source.

Electronic devices can be designed and made and certified safe for use in an explosive atmosphere, but that's an expensive process to go through. That's what you need to do to convince insurance companies you were not negligent, and to let you sleep soundly in the knowledge you've not created a time-bomb.

Since you told us the application, we cannot avoid warning you not to attempt this.

So, given the warning above we can proceed...

Yes you can use a HX711 for this. But strain gauges perform very poorly in this kind of application. They stretch over time and have to be re-zeroed regularly.

Think of any kind of digital scale you have ever used. You always zero it when switching on. Not because of the switch but because that is usually a convenient time when there is no weight on the scale.

Maybe you can zero every few months when the bottle is empty or maybe you can do it at the start of every camping trip.

Personally, I would research other methods first.

@MorganS, thx for your comment.
I will look if there is a way to only put the load on the sensors when the system is switched on.
If I cannot bulld this I will look for an other method

You don't have to unload the sensors when unpowered. You just need a way of unloading them and hitting the "zero" button for a moment.

When I have to unload the sensors when I start the system I have to install something to unload them remote.
To protect the sensors during driving its then easy to install something that is unloading the system when it is switched off.