Need help with project Prepaid Water Meter

[purplefairie]

hi. i have a project about "Prepaid water meter" where when there is credit in the smart card, water will continue to flow to the house until there is no more credit which will automatically close the valve.

I was wondering how to connect the water sensor and the counter together with the microcontroller. Is it possible to be done? Can I use RFID for the prepaid part?

Thanks.

 

[nandhu015]

I was wondering how to connect the water sensor and the counter together with the microcontroller. Is it possible to be done? Can I use RFID for the prepaid part?
Thanks.

Yes, you can do connect flow meter(sense the quantity of liquid) and RFID to microcontroller.

Even a simple microcontroller can handle this project.

Good luck

 

[horace1]

you could use a flow meter, e.g.
Browse for Products | CPC

typically such devices operate a switch or give a pulse for a given flow rate. You can feed this into a digital IO pin of a microprocessor and sense changes either by polling the pin or using interrupts, e.g. input change notification of a PIC24 see section 11.5 of
PIC24HJ64GP502

using a timer one can count the pulses/second getting litres/sec.

 

[purplefairie]

Thank you to the both of you about the flow meter.

Now I want to ask about the prepaid part of the project. I'm having confusion about that part. What do I need to do? Can the RFID card read any prepaid credit in some contactless RFID card? Or is there any other way instead of using RFID for prepaid?

Thanks.

 

[horace1]

what you need is some simple and cheap way of doing. The only stand alone prepaid system I implemented used prepaid cards with magnetic strips. A magnetic card reader read the amount and then wiped the strip. However, the card reader was very expensive (approx. £500).
Is your meter connected to the internet, e.g. for transmission of water usage? If so your users could logon to a server and pay using their cried card. The meter, when the exsiting funds were running out, could contact the server using TCP to check for new funds.

 

[purplefairie]

My meter is not connected to the internet. It's like a normal water meter just with the prepaid part added to it. I'm not having any idea on how to implement that.

 

[horace1]

what you need is some simple low cost system. there are some examples in
Electricity meter - Wikipedia, the free encyclopedia

Try doing a web seach on "low cost pre payment" and see what it turns up