This effect started off as a plain plastic silhouette type Xmas light, with a string of traditional tungsten lamps on it. I made a small inline capacitive dropper as used in many small LED mains powered lamps. It consists of a 100nF 400V capacitor with a 1 Megohm discharge resistor across it, and a 1K half watt resistor in series with a bridge rectifier made up of four 1N4007 diodes. I slid a bit of heatshrink sleeve over the hard wired PSU circuit, hot melt glued one end, and then potted it all in two part resin for safety. The output of the PSU is rectified and current limited mains voltage which lets me run all of the LEDs in series on the UK 240V mains supply. I then removed all the original push-in lamps in the effect and took the glass lamp out of it's base, replacing the lamp with a bi-colour flashing LED. You can't use the RGB flashing/fading LEDs in this arrangement because the pulse width dimming means they frequently go open circuit in normal use and with this circuit the open circuit voltage would be high. The LEDs I used flick alternatively between blue and green chips and since one LED is always on they are OK in this application.
I bent and cropped the leads of the LEDs and also used a pair of snips to crack the lens end of the LED off to give it a wider viewing angle. The irregular fissures of cracking the end off is a good visual effect. I then put the LEDs into the series string of sockets, noting the polarity. You MUST get the polarity right or the LEDs will be damaged with the high reverse voltage.
The end result is an effect where every point of light alternates between green and blue at its own speed, giving the effect of swirls and waves of colour on the effect.
The fact the PSU puts out unsmoothed DC meant that these LEDs flickered randomly when exposed to bright light. This is because the chip in the LED is exposed to external light and it affects the stability with rough DC. I tried a 100nF cap across the DC output and it fixed it immediately. However, I kinda liked the wild flickering so didn't use the cap in the end. The effect works fine in the dark.
You may notice a duff LED on the left which is missing a colour. These were cheap ebay LEDs and you inevitably get a duffer or two. It's easy to change them out though.
I put this up in my window for Xmas. It only draws about a watt of power which is very "eco".
I bent and cropped the leads of the LEDs and also used a pair of snips to crack the lens end of the LED off to give it a wider viewing angle. The irregular fissures of cracking the end off is a good visual effect. I then put the LEDs into the series string of sockets, noting the polarity. You MUST get the polarity right or the LEDs will be damaged with the high reverse voltage.
The end result is an effect where every point of light alternates between green and blue at its own speed, giving the effect of swirls and waves of colour on the effect.
The fact the PSU puts out unsmoothed DC meant that these LEDs flickered randomly when exposed to bright light. This is because the chip in the LED is exposed to external light and it affects the stability with rough DC. I tried a 100nF cap across the DC output and it fixed it immediately. However, I kinda liked the wild flickering so didn't use the cap in the end. The effect works fine in the dark.
You may notice a duff LED on the left which is missing a colour. These were cheap ebay LEDs and you inevitably get a duffer or two. It's easy to change them out though.
I put this up in my window for Xmas. It only draws about a watt of power which is very "eco".
Where can you get those Leds? I can't seem to find them
I kinda prefer the shimmering ones that look like someone's shorted them out (usually encased in plastic but in snowflake form , with 2 shimmer bulbs per snowflake. Basically look like someone has um plugged themselves into the wall look :O
the left light is broken? only blinking blue and not green:P