Make your own camera head
All you need is light-tight box with a hole cut out of one side for your eyes and a pin hole above. Inside the box, opposite the pinhole is a sheet of white paper. As long as your viewing hole has some kind of fabric around it for light-tight seal, you're good to go. As for the lens hole, you can start with a standard hole punch, which will give you a bright picture, albeit blurry. From there, you can get more advanced and poke a push pin through a small piece of aluminum cut from a can. Be sure to sand down the rough edge of the pinhole if you use aluminum. That's it! See a great book "Reframing Photography: Theory and Practice" By Rebekah Modrak and Bill Anthes for more details.