What you'll need for each light:
1 - 1/4 inch white hinged screw cover. About 70 cents for 2 at any Hdwe store.
1 - Little Dot SMD LED Accent Light ($1.99) with built-in resistor for 12 Volt DC operation (9~14.8 range)
Purchase from http://www.superbrightleds.com
After rebuilding my deck, I needed some step lights for accent. The ones I found on the net cost more than I thought they were worth. ($80 to $140 for ten. See photo example) The manufactured kits also required large special size holes (some up to an inch), and being able to get an exact replacement to fit the existing hole when one of them died concerned me. Since I like to DIY it, I decided to build my own.
Searching thru the specialty hardware drawers at my local Lowe's, I decided a round, hinged screw cover would be what I could use to enclose a small LED. I found an LED at Superbrightleds.com. The small, flat Little Dot SMD LED was just what I needed. The screw cover needed just a slight modification to allow centering the little LED. Although the Little Dot had a sticky back, I added some hot glue just to make sure it stayed in place.
Installing them to my deck steps required just a small hole to stick the wire thru and more glue to hold the screw cover in place.
A small screw could also be used. I didn't do any current/voltage calculations, I just connected them to the existing old 12VDC
low voltage transformer that I had used for the incandescent post lights on my old deck. You can buy 12VDC power packs at Superbrightleds.com My lights (25 total) have been working now for about 5 months without any problems.
Each light cost me about $2.35 instead of $8- $14, and buying a few extra LED's to took care of future replacement concerns.