Hii, I have read your requirements... Fully understand what are you looking for... I can assure you that me and my team can deliver you exactly what you want.. we have worked with optical beam technology smoke detectors for large area installation... so we know what are the challenges we have to face in this kind of project... We can give you Circuit diagram, PCB layout, Project Report, BOM etc... if you want I can give you a prototype also... And I'm from india too so there will be no communication gap between us... we can easily understand our talks.. I can suggest your pasrt wich are available in indian market for ease purchase... It will be a very interesting project... Looking forward to work with you... thanks...