dumb opto -ish kinda question using xmas lights

[pinkjimiphoton]

guys, if building a phaser or vibe or something where you'd use a vactrol of the old led/ldr combo,
i read over and over that they don't react the same as incandescent lamps.

so i was just thinking this morning, what about them little colored christmas lights that come on strings? they seem to be good for about 3v or so if memory serves, and come in colors... so maybe a yellow one would be  a good match for a photo resistor? and being incandescent, maybe they'd "fade" in and out in a more "organic" way than the usual leds...

just thinking... is this worth trying on the breadboard, or just a waste of time?

[Ice-9]

guys, if building a phaser or vibe or something where you'd use a vactrol of the old led/ldr combo,
i read over and over that they don't react the same as incandescent lamps.

so i was just thinking this morning, what about them little colored christmas lights that come on strings? they seem to be good for about 3v or so if memory serves, and come in colors... so maybe a yellow one would be  a good match for a photo resistor? and being incandescent, maybe they'd "fade" in and out in a more "organic" way than the usual leds...

just thinking... is this worth trying on the breadboard, or just a waste of time?

Sounds a reasonable idea Jimi, but heck you'd need a big box to fit 48 Christmas tree lights in or are you planning on a footswitch at the base of your Christmas tree.

On the 1st phase of Christmas my true love gave to me........

[armdnrdy]

Just like Jimi....
As the whole world is switching over to LED lighting...Jimi wants to revert back to incandescent!  

We should call you Retro Jimi Photon!

Seriously though....unless you have strings of incandescent Christmas lights up in your attic or down in your basement, it might be kind of difficult to find anything other than LED lights.

http://en.wikipedia.org/wiki/Bans_of_incandescent_light_bulbs

Edit:
it looks like you can still find them, but they can't be shipped to certain states:
http://www.homedepot.com/p/Unbranded-Professional-Series-100-Light-Multi-Color-Mini-Light-Set-with-White-Wire-Set-of-2-37-730-20/204629281?N=5yc1vZc3tbZ1z11erb

I never though that I'd see the day when Christmas lights would be considered contraband! 

[GibsonGM]

Don't get me going, LOL.

Check out the local 'dump store', man. I bet I've got 2,000 lights kicking around somewhere in a Rubbermaid! 

This has me curious now!    Last ditch would be to hit Radio Shack and get a small-voltage bulb....but Xmas lights are FREE!

[pinkjimiphoton]

 

i didn't mean a whole string, just one or two... they aren't all that much bigger than a 5mm led.

but if it works, and well, hell, a string of a 100 lights could last for decades i'm thinkin'.

you can still get them at job lot kinda surplus places, even tho they're banned.

i don't care for he neon light bulb things... they tend to bug me. stockpiling real ones.

but.... that said... so , it should work, right? i'm just thinking the rise/fall time may be better for say, a univibish kinda circuit.

[Ice-9]

i didn't mean a whole string, just one or two... they aren't all that much bigger than a 5mm led.

but if it works, and well, hell, a string of a 100 lights could last for decades i'm thinkin'.

you can still get them at job lot kinda surplus places, even tho they're banned.

i don't care for he neon light bulb things... they tend to bug me. stockpiling real ones.

but.... that said... so , it should work, right? i'm just thinking the rise/fall time may be better for say, a univibish kinda circuit.

Yeah Jimi, I know you only meant 1 light, but hell bells man, a 100 stage phaser could be the bollocks, 'Colosus Phaser'  anyone. The enclosure size would be about the same size as the Colosus

On another idea , if you have plenty to use maybe a good use as a bypass/effect indicator bulb but I imagine the current draw may be high compared to an LED.

There is no reason why you can't control an LDR with it, what will make a difference though is weather they dim and light at a good ratio, so some aspect of altering the drive circuit to the bulbs may be needed.

[digi2t]

Off topic alert....

Yo bro, if your Unkie Luddy needs any of those incandescent bulbs that are on the fall board, let me know, I might have some red ones kicking around. And while I'm at it, I have some orange, and green, Plexiglas in stock as well. I used it to cut small squares to replace the missing color lenses on my Ludwig units. these are what give the control panel switches their particular color. I can't remember the original lens size, but although my sheets are thicker, once cut it glues in easily with Crazy Glue.

You may now return to normal Christmas programming.....

[pinkjimiphoton]

i didn't mean a whole string, just one or two... they aren't all that much bigger than a 5mm led.

but if it works, and well, hell, a string of a 100 lights could last for decades i'm thinkin'.

you can still get them at job lot kinda surplus places, even tho they're banned.

i don't care for he neon light bulb things... they tend to bug me. stockpiling real ones.

but.... that said... so , it should work, right? i'm just thinking the rise/fall time may be better for say, a univibish kinda circuit.

Yeah Jimi, I know you only meant 1 light, but hell bells man, a 100 stage phaser could be the bollocks, 'Colosus Phaser'  anyone. The enclosure size would be about the same size as the Colosus

On another idea , if you have plenty to use maybe a good use as a bypass/effect indicator bulb but I imagine the current draw may be high compared to an LED.

There is no reason why you can't control an LDR with it, what will make a difference though is weather they dim and light at a good ratio, so some aspect of altering the drive circuit to the bulbs may be needed.

hell, i'll try playing with one then and see what happens!!

Off topic alert....

Yo bro, if your Unkie Luddy needs any of those incandescent bulbs that are on the fall board, let me know, I might have some red ones kicking around. And while I'm at it, I have some orange, and green, Plexiglas in stock as well. I used it to cut small squares to replace the missing color lenses on my Ludwig units. these are what give the control panel switches their particular color. I can't remember the original lens size, but although my sheets are thicker, once cut it glues in easily with Crazy Glue.

You may now return to normal Christmas programming.....

dino, if YOU need them, i found a local source for the "grain of wheat" lamps for the ludwig, they fit inside the original plastic cases for the lamps in the fall board part.

i think i'm ALMOST ready to send you my board along with a check for constructing it for me... thanks so much bro. there is no way in hell i can see good enough at this point even with my loupe to be able to pull this off... funny, i wrote this backwards, it looked like shit... lol

we just bought a house, so it's gonna be a while still... oy.... lol

[Mark Hammer]

I would think that any "magic"  in the sweep is not specifically in the bulb itself, but rather the way in which the bulb filament's properties, and the LDR's on/off properties, complement each other.  Certainly the cosmetic aspects of havinga tinted bulb glowing on and off are appealing, but there's no guarantee the LDRs you may have selected to use with the bulb will have their best qualities brought out by the bulb.

Myself, I think probably the optimal is to whip up a 2-op-amp LFO that lets you adjust the rise and fall time, and tweak those two parameters until the sweep sounds right.  That, and an LED that responds as fast or slow as you want, will likely get you where you want to go.

[mac]

The filament resistance is a function of temperature.
When there is little current the resistance is higher so the rise time is different than leds.

Just like Jimi....
As the whole world is switching over to LED lighting...Jimi wants to revert back to incandescent!  Grin

... and tube amps 

Jimi, what about the filament of old used tubes?

mac

[Gus]

So control the drive to the LED to mimic an incandescent.
If I was to design something for this I would investigate  a variable during each cycle PWM(high enough frequency to average out for the LDR) drive different for the rise, hold and fall.
LEDs don't dim well with a resistance control often the dimming is an average brightness from pulsed drive
A microcontroller might be the best way to do this

[pinkjimiphoton]

I would think that any "magic"  in the sweep is not specifically in the bulb itself, but rather the way in which the bulb filament's properties, and the LDR's on/off properties, complement each other.  Certainly the cosmetic aspects of havinga tinted bulb glowing on and off are appealing, but there's no guarantee the LDRs you may have selected to use with the bulb will have their best qualities brought out by the bulb.

Myself, I think probably the optimal is to whip up a 2-op-amp LFO that lets you adjust the rise and fall time, and tweak those two parameters until the sweep sounds right.  That, and an LED that responds as fast or slow as you want, will likely get you where you want to go.

diggit bro, i agree... led is the way to go these days... but i was just thinking it may be neat to make a "christmas tree" pedal. (i'm budhist, so no religious affilitation here... tho wiccan can apply too. i was married to a witch for 17 years til she died of lung cancer at 38)

i've read many times people say that led's don't react the same... so i was just thinking, what's something that's relatively ubiquitous here?
and it may be cool.

the reason i suggested yellow is i believe that is the frequency of the light spectrum that ldr's respond to best from what i've tried to glean reading stuff. i figure an incandescent light has to have slightly different rise/fall times as it's lit and dimmed. i doubt it makes enough difference to matter, really, but then some peeps claim they can hear differences in batteries and cords and stuff. not me. my ears aren't that golden.

i was just thinking it may be a neat way to re-purpose a relatively common object for us diy addicts.

The filament resistance is a function of temperature.
When there is little current the resistance is higher so the rise time is different than leds.

Just like Jimi....
As the whole world is switching over to LED lighting...Jimi wants to revert back to incandescent!  Grin

... and tube amps 

Jimi, what about the filament of old used tubes?

mac

that's a cool idea mac!!! i wonder if it would work well... if i recall tho, filaments in the heaters glow for a noticeable period after power is applied or removed. that may actually work perfectly, i'll try it when i get a chance to play with stuff again (if i remember... i have the memory of an elephant.... with a pre-frontal lobotomy... or is that a free bottle in front of me??? lol)

So control the drive to the LED to mimic an incandescent.

so... you'd want a sine wave for that, wouldn't you?  or would a sawtooth be closer? i honestly know nada about how they work at this point, was just an idea bro.

If I was to design something for this I would investigate  a variable during each cycle PWM(high enough frequency to average out for the LDR) drive different for the rise, hold and fall.

if ya get a wild hair across your posterior, gus, i would LOVE to see what you come up with, and be more than willing to try and build a proof-of-concept for you...

i'm getting ready to do YOUR take on the suzy q idea, too, btw...

LEDs don't dim well with a resistance control often the dimming is an average brightness from pulsed drive
A microcontroller might be the best way to do this

yah, but then you have to deal with code and stuff, right? i'd rather mess with analog thru hole stuff still at this point.
i realize digital control is hip, but man, i'm just beginning to get a tiny inkling here, and that's stuff that's all way above my paygrade.

i was just figuring what better way to simulate and incandescent bulb than with an incandescent bulb?

if i can get to mess with stuff tomorrow when gineen is out,  i'll try and breadboard a magnavibe or something to see if it works out.

thanks for the feedback brothers. very appreciated!!

[PRR]

> When there is little current the resistance is higher

Resistance *rises* with temperature.

It is useful to recall that a "120V 60W" lamp, which draws 0.5 Amps when hot, pulls 3X to 5X the current on a cold-start. Which is part of why incandescents typically "blow" at turn-on.

[Brymus]

You just reminded me of something,not to hijack your thread,sorry
But I recently bought a old Baldwin organ for very cheap cause the guy said it used light bulbs not transistors for power.
I thought cool he must mean tubes...Anyway got it home took it apart and look what I found,are these actually light bulbs used as an electric component or are they small tube diodes?
There are quite a lot of them they are all paralleled to resitors from the way it looks.
Boy was I dissapointed even the power amp uses large Ge transistors,there are a ton of top hat Ge trannies(from General Electric LOL)
And a handful of what look like Si trannies,that have gold pins and look like flying saucers on 3 legs,they must have been top shelf items back then.
BTW the organ works fine in spite of some very old Mallory and Sprague electros.It even has a rotating horn style leslie tone cab on one side.

[Brymus]

IF they are light bulbs, AND I scrap the organ for parts I will send you a few Jimi   

[tubegeek]

If I had to guess, the bulbs in that organ are there as part of the oscillator circuits. Incandescent bulbs, with their varying current-dependent resistance, can be used to keep an oscillator circuit from over-gaining itself into distortion. See "The comprehensive phase shift oscillator thread" for some more discussion on this.

http://www.diystompboxes.com/smfforum/index.php?topic=106566.0

Two guys named Hewlett and Packard founded a somewhat successful company in their garage based on this fact!

And:

I have a few strings of Christmas tree lights in my basement because I've wondered just the same thing. I would guess that an incandescent lamp is yellow enough to match well to an LDR even without the colored filter but what do I know?

[GibsonGM]

I just found a string of like 1,000 of the suckers.  We don't need them, so it's PLAY TIME!   I have a schema of a 2-stage LFO someone designed kicking around here somewhere.   This could be cool...you could make an "oven" for the light, and arrange LDR's around the lamp.  Seal the sucker up, you have a little mothership of goodness. 

Tweak time....

[duck_arse]

But I recently bought a old Baldwin organ for very cheap cause the guy said it used light bulbs not transistors for power.
I thought cool he must mean tubes...Anyway got it home took it apart and look what I found,are these actually light bulbs used as an electric component or are they small tube diodes?
There are quite a lot of them they are all paralleled to resitors from the way it looks.

I'd put my money (and I've always lost it when I've said) on those being neon lamps. they strike at about 90V usually, so they get a series resistor for mains work. they glow orange along the internal elements. most often used as "pilot lights", like on mains switchs, but also used in the trem section of valve amps.

I'd like to know what that orange thing is to their right.

[pinkjimiphoton]

nice!!!

yeah, in the organ i've seen those before too, it's usually something to do with the vibrato in it, but i have also seen them used almost like resistors, they vary resistance as paul said by heat but also frequency... i used to gut organs all the time back in my tube days, now i kick myself in the ass for trashing literally THOUSANDS of ge transistors... and often NPN ones with good gain ranges (as i've learned since)

mike... let us know how ya make out!!

i'm gonna take a crack at the experience pedal that came in yesterday (ot) today i think... 2 of the 4 pots are snapped internally, and at least two of the 3904's were squished and shorted.

edit:

the orange thing just to the right is a capacitor array, i still have some in my junk drawer... some are r/c networks in multiples others are multiple caps in one case.  or it could be an inductor, too, i've seen those look like that too. i used to swipe 'em from organ chassis and play with 'em in tube circuit gain stages... can get some cool sounds abusing them.

[GibsonGM]

Wow, ok...we approach some fundamental barriers here, and maybe learn a little bit about WHY effects went to LEDs from bulbs when the technology came available!

Seems incandescent-type bulbs react a lot differently than LEDs. I've never messed with anything but LEDs in this application...so I turn to my "Go-to LFO", a double opamp thing that generates a ramp quite nicely.     The LED tested out, so it works fine. Scope confirms this.

BUT - the Xmas light will not light.   OK, I say - it just needs more juice.  So I bias it with my variable power supply, try a bunch o voltages.  1V, 3V, etc.
No go.....the light will light up ok with some bias, but will not respond to the small voltage swing my LFO provides!   I mean, it puts out very roughly 2v to 3 v and back again.    THE LAMP BUFFERS THIS VARIANCE; you see no change.   

Interesting, and back to the drawing board.    I am betting that old-timey oscillators for bulb use had a lot more swing to them, daddy-o. 

Maybe something could be rigged using a power transistor or FET, I don't know just yet!  Learned a bunch of stuff, tho.

Xmas lights like shown in the Home Depot link above pull~ 130mA at 3V, 166mA at 4.5v, and 200mA at 6v.   High and linear draw.

Now think about that little LED running on less than 20mA, and how much easier it is to toss him around, make him do what we want!

This was worth looking at, maybe if I get time I'll rig up something I can add to the LFO to drive the things....