Three photos attached
first: Components, LED's, Capacitor's, telephone wire and Plastic tubing (missing diode, could not find one laying around.
The LED's are standard 2mm diameter PC board type. (note one lead is longer than the other-important cuz that designates polarity). Color-I prefer yellow or orange. I tried red, green, yellow and orange. The red and green are interesting but yellow and orange are easier on the eye. IMO.
Diodes are wired in series with the capacitor and the diode. About 25 LED's can be strung across one stair. Each diode drops about 3v it when lit up. Total drop across this string will be about 75v. The capacitor will current limit the string to 2.2ma peak. The LEDS will operate on a 35% Duity cycle (the diode blocks the negative half cycle and the LED's wont turn on until their forward voltage is exceeded).
Power per stair tred will be about 120mw. ( ~0.1watt per stair tred. For 13 step stair thats ~1.3 watts. For one month thats about 1KWHr or 25 cents per month at $0.25/KWHr)
The eye responds to peak light intensity so even though the LED's average very low current and low duity cycle. We percieve it as quite bright.
The capacitor I use is .1 micro farad. That sets the peak current to 2.2ma. That is about one tenth the current necessary to cause muscle clamp on if you should accidently get hold of the wires while its on. You would feel a tingle but nothing remotely close to life threatening. Quite safe for children and dogs.
(NEVER, NEVER, NEVER use electrolytic capacitors. They will blow up when reverse biased like a shot gun.)
I use 2mm LEDs they are small enough to slide inside the plastic tube and large enough for fumble fingers to handle. The also have standard leads greater than 1 inch. I take advantage of that by folding the long lead back over the diode and soldering it to the next diode in the string. That sets the spacing of the diodes and eliminates extra wiring between LED's.
One string consists of 25 diodes and one capacitor at one end. A wire is soldered to each end of the string. The string is inserted into the plastic tube and the ends sealed with silicon glue.
Each tread has the plastic tube mounted below the tread at the top of the riser. The marble stairs had a gap that i was able to shove the tube into with no additional mounting effort.
The wood stairs required a molding from Orchard Hardware to hold the tube and act as a light baffle. The molding is normally used to trim 1/4inch wall paneling. Its perfect, the rounded front section is where I bonded the plastic tube. The molding was glued directly to the bottom of the tread. I even painted the front of the trim baffling to blend with the riser color.
More to come if u want it.