Im guessing clear leds with the standard light output, I have some red ones like that
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This is surprisingly low for dark resistance, were they completely isolated from any light source.
The only reason I ask is that I have been charting the results or various led-ldr combinations for vactrol use.
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Diffuse just means the housing is frosted/translucent to spread the light over a larger solid angle. With a transparent housing the light is mostly emitted in a small solid angle forward. Like frosted vs. clear incandescent bulbs (except clear bulbs also spread light in all directions, frosted bulbs just spread the light from the filament around to make a less concentrated source), for those decrepit enough to remember those.
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I found some here with a warm white color that matches your description.
I totally agree with you.
After reading your comment I decided to recheck the LDRs here.
What I did earlier was measure them by just cutting the light with my hands. I tested again using a black tube wrapped in black electrical tape and the results were very different.
The 5mm ones purchased from digikey measured around 38K earlier and now measure around 192K, which I still think is too low. (The label on the packaging where they are stored shows NTE 02-LDR2 - But I’m not sure, I bought many types and they could be mixed…)
I found the datasheet and I see that it makes sense with what I found:
NTE LDR Series
I measured others in a 10mm TO-8 metallic package (Advanced Photonix NSL-6910 and NSL-5910) and these measured around 52K (6910) and 88K (5910), incredibly very low.
All the other 5mm ones stored here measure infinite resistance in the dark, these are the most generic type.
Edit:
Please disregard the measurements mentioned in this post. I noticed that my multimeter is damaged. It’s a smart touch digital model and it’s giving me different readings (sometimes random) every time I turn it on. When I get a more suitable DMM I will retake these measurements.
Apologies for the inconvenience.
Great comparison. Thank you.
Or decrepit enough like me.
I need incandescent bulbs to illuminate the spaces where I stay for a long time.
If I’m exposed to LED lighting for a long time, in addition to the visual disturbances, I get a terrible migraine. I have some between 60W and 100W still in stock, as they are becoming difficult to find.
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Yes, as I said it was “a very crude measuring of resistance”. The actual figures in a sealed enclosure are likely much higher, although I do not think that one can manage such an enclosure unless one goes at considerable length (e.g. making a 3D printed enclosure, enclosing the LED/LDR in baked clay, etc). So my measuring was crude, and I though that this was enough thinking that I will not manage to keep all light out anyway… In other words, the crude numbers are likely closer to what you should expect in the actual build compared to the ideal numbers you find in the LDR datasheet.
The general message is that this build does not require any critical parts. You can probably make it work with any LDR as long as you play with the resistance around the op amp and find the right LED (and its neither expensive or difficult to find different kinds of LEDs to try them out).
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Me! Me! That’s me! I remember them!
I’ll get my coat!
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Same here, too much LED and i get a kaleidoscopic migraine. I use a daylight bulb in my work lamp and use beige reflectors with LEDs
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In addition to the various options for LDR and LED it’s also worth looking at the vactarol design.
Adding a first wrap layer of white paper or shiny foil before the shrink wrap or electrical tape adds to the distribution/diffusion. Sanding the LED, yes or add a single layer of translucent book tape to the LDR to assist in saturation. Adding a gap of a few mm also works well.
Experiment!
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And the nausea? Very bad…
I tried warm white color LED lights. They are more comfortable, but I still have visual disturbances, maybe it’s something about the frequency flicker/fluctuation in the LEDs.
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Very good tips. Yes, experimentation.
Correct me if I’m talking bullshit, but I realize there is no absolute vactrol type for all applications. Whether an industrial or DIY vactrol, each project will require different characteristics from it.
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No such thing as a DAQ* in this forum. Ever!
Vactrols do vary and experimentation is always a good call. I made a swanee whistle controller by sliding a dim led on a stick up and down a brass tube with an ldr at the other end.
Why brass? Because I know paper, black plastic and steel straws didn’t work or give me the results i needed.
Why dim? Experimenting with “brightness” illustrated what led and level worked best.
*DAQ = Dumb A$$ Questions
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At the risk of straying too much off topic, Ive gotten good results* with a fairly simple setup puting LED and LDR on a small breadboard an covering it with one of those little black ABS project boxes, with tiny holes for the wires coming and going from the breadboard and withhe LDR facing the LED as close up as possible.
Project box:
Like the top right one.
- I was able to get over 1000:1 change in resistance.
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Good idea for a “dark room” vactrol tester.
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Or a darkroom for an array of either ldr or LED and a disco mirror ball.
Used to use 35mm film cases; a rare scrap find these days. Thank goodness for blood test strip packs i get free in Scotland having been awarded what my youngest calls Diddi-biddis!
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Nooo, don’t tell me that…
My wife is worried that I might have a hoarding disorder…
Perfect! Now you need to build a module named Diddi-biddis!
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Challenge!
Plus 20 characters
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Here’s my layout for the Kassutronics KS-20 VCF
The BOM and all other info can be found here: https://sandelinos.me/diy/ks-20-filter/
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Here’s my dual VCA based on the circuit from Electric Druid’s “Design a Eurorack Vintage VCA with the LM13700” article.
The BOM and all other info can be found here: https://sandelinos.me/diy/LM13700-dual-VCA/
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