Prepaid energy meter with smart card

Projects General Guidance
1

I'm trying to help a homeowner who rents her house to tourists for the summer. She lives quite far from where I live and she doesn't have a clue about electronics, electrical installations or anything like that. I can't go to her place and help with the installation, but only talk to her on the phone. She'll have to hire somebody locally to do the installation for her. By the way, local electricians were of no help finding a solution: it's a problem that, apparently, they never faced before.

This is the problem: the fee for the house is fixed, all included. Unfortunately, some guests tend to abuse this and are very careless with their energy consumption. Raising the fee for everybody would be a marketing blunder and scare away the more parsimonious (and often, returning) guests, who might feel the raise is unjustified.

This is what I have in mind. Upon arrival, the guests are given, at no extra cost, a smart card or some kind of token that allows a reasonable amount of energy to be consumed. To turn on the electricity, they put the card into some device. If they stay within that amount during their stay, nothing special happens. If they consume more than what's on the card, however, they'll have to pay for an extra card with more energy on it to continue using the electricity.

The device should allow the guests to monitor their consumption and the credit that's left on the token. The importance of the token should be made evident: if it is removed (or drained), lights off. If the token is put back (or a new one is used in its place), lights on. This is why a physical token of some kind is preferred. The tokens should also be cheap, in case a guest carelessly throws away a drained one when it stops working.

The system should be reasonably tamper-proof or at least tamper-evident. The house does have an alarm system that could be connected to it.

The first thing I searched for was a commercial device, but I found nothing within a reasonable budget and tailored to private homeowners. I only found big stuff for hotels or campsites.

I my mind, a possible solution would be based around a controllino, maybe a contactor, a token reader (magnetic card, smart card) and a display.

Any ideas?

2

It would be easier to have a prepayment meter installed, preferably one that takes coins

3

Consider taking a deposit for energy and note the meter reading. When they leave the energy usage can be calculated and the excess deposit can be refunded. You can do a lot with smart meters. This will all critical stuff to run without changing the wiring.

4

Depends on in which country you are.

Clearly UKHeliBob is from the UK where this particular practice has forever been endemic. Perhaps you should seek the equipment from the UK. :grin:

Let us warn you - you will not be able to better the price on what is commercially available, even if you could build it yourself.

5

Also it needs to be accurate with defined tarrif that is provable , as said go buy one they are cheap .

6

I think a quite important question is: what country are we talking about?

In the end we probably get the solution of gilshultz, maybe extended to a remote read out (take a look at smartpi).

7

Probably Italy

8

Now over 24 hours, this may be a dead thread. :roll_eyes:

9

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