A member named Broken Angel PM'd me this message:

Hi.. I m new here,and don't know about any one,hope i would get frank with every body very soon.. Little bit into about myself,I m an electrical engineering student.. Actually my Analog electronics teacher has assigned me a very interesting project "Home security system",I have added the features of flood,fire,intruder and natural gas leak alarm circuits.. I have found almost every circuit except natural gas alarm circuit.. I request you all to send me this circuit as soon as possible,my email address is <Email Removed> .. I Shall be very thankful to you.. send me before 18-April-2011..

Unfortunately I have tasks of my own to complete, and with little time to spare. Perhaps members on the forum can help you, but I would encourage them only to help, not to give complete answers. I have removed the email for discretion purposes.

 

I have no words to express that how much i m thankful to u,any way thanks a bunch,i would be very happy if u would become my best buddy. I need to know about you,so plz introduce urself.. waiting for ur reply..

 

Did you try a Google search for "natural gas leak alarm circuit"?

 

Hello,

I also recieved an email with the same text.
As I will not give answers in emails, I do it over here.

We are not an answering service.
You will have to do your own work.
Show us what you got and tell us where you got stuck.

I have here a PDF on gas sensors:
Gas detection

This is a link from the EDUCYPEDIA page on Miscellaneous sensors

Bertus

 

I've bought this set, built and tested it. And it works.