Episode 70 - DIY Electroluminescence: Great Light Without The Shocks

[gattis93]

Hey, I don't know if its just firefox 3 or what but the 2 links in the show description are busted, they go to revision3.com/systm/kiki/"(the site it should go to)", great show though. Just thought i'd let you know

[mikec]

gattis, I have the same issue as you described.

[cybersuchus]

Originally Posted by aaronbond

anyone else notice the high-pitched frequency when the EL was powered? it was abit annoying. is that always the case?

Yeah, I caught that too. It reminded me of the whine I hear from the old CRT televisions when they are turned on, only a tad louder.

[haku]

Another great episode guys! a shame EL sheeting is so expensive (especially UK suppliers) and I was hoping for a little more creativity in the ideas but it was still good to see, well not very well - for those episodes where you need to film short pieces in the dark wouldn't a basic DV camcorder with night vision capabilities see the stuff the studio cameras can't?

Originally Posted by aaronbond

anyone else notice the high-pitched frequency when the EL was powered? it was abit annoying. is that always the case?

I believe so, the DC to AC inverters I've used/seen all make a high pitch whining sound but not all are that loud.

The EL backlighting of my (really good) Metrix MTX3282 multimeter & Philips ProntoNeo remote both make a notable noise when lit.

But you can cut down the noise by housing the inverter in another box like I did with the one for the EL wire in a custom mp3 dock:


I wonder if potting the inverter board+components would eliminate or amplify the sound?

[davmoo]

Originally Posted by aaronbond

anyone else notice the high-pitched frequency when the EL was powered?

Thankyou. I was wondering if I was the only one who heard that.

And yes, most EL inverters do that, but also most people can't hear it.

[rogerchang]

".... was still good to see, well not very well - for those episodes where you need to film short pieces in the dark wouldn't a basic DV camcorder with night vision capabilities see the stuff the studio cameras can't? "

Yeah sorry about the the low light issues. Video cameras by their nature require a significant amount of light to produce acceptable contrast and detail in a picture More so than say a film based motion picture camera. After looking at the capture probably should've yanked out my still camera and took stills for a better reflection of what we saw in the studio.

Night vision capabilities could work but anything bring would end up various shades of green. Not sure if that would've brought the idea across either. But will make a note of it for future reference... and when we get a camera with that functionality in.

[cptpatriot]

I was fascinated by the EL sheeting but any idea what the life of the sheets are? Are there different light levels available in these sheets?

[haku]

Originally Posted by rogerchang

Night vision capabilities could work but anything bring would end up various shades of green. Not sure if that would've brought the idea across either. But will make a note of it for future reference... and when we get a camera with that functionality in.

I've found it's always tricky trying to take pictures/video in low light, a farily neat feature of some DV camcorders is the ability to have longer shutter times, not so useful for motion but for taking a still of a low lighting project with a tripod it works pretty well, I did a test with my DV camcorder in night vision mode (mainly it slides the IR filter away from the CCD):



I think the camera is only capable of about 1 LUX whereas I've seen some high quality bullet cameras that can see colour in much lower light, the last picture had gamma+contrast applied to it which helps represent what you can see with your own eyes.

[haku]

Originally Posted by cptpatriot

I was fascinated by the EL sheeting but any idea what the life of the sheets are? Are there different light levels available in these sheets?

EL wire/sheeting brightness & lifetime are linked, like the famous Bladerunner quote "The light that burns twice as bright burns for half as long". Also, as was pointed out in the episode, the smaller the EL sheet (or shorter the EL wire) the brighter it will be.

It won't suddenly switch off but gradually fade over time, this page & this page have some info on how long EL lasts.

An easy way of dimming EL is to reduce the voltage going into the inverter, over-volting an inverter will most likely burn out it's components though, like my friend found out by plugging a 12v DC input rated inverter into a car battery charger instead of a car battery which worked for a short time and then died.

Try these at your own risk, I know nothing about electronics.

http://electronicdesign.com/Files/29/6308/Figure_02.gif
joshua.raleigh.nc.us/LM555-inverter/LM555-inverter.pdf
http://www.geocities.com/talkingelec...roject-P2.html
http://electronicdesign.com/Files/29/6400/Figure_01.gif
http://www.talkingelectronics.com/pr...itELine05.html
http://www.datasheetcatalog.org/data.../MC33441-D.PDF