NeoVibe

[carrejans]

Ok, so I have to restart this thread; the previous one diappeared, because Aron is working on the forum.

So, I'm going to build the NeoVibe in a while. I purchased all the parts, but have a few questions about them. I searched the forum, and found a lot of threads about the neovibe, but couldn't find an answer to my questions. I also read "The technology of the UniVibe" of RG Keen; very great article. Thanks a lot RG for all the effort you put in this diy community; I hope they will repay you with buying your book.

Lamp: my local shop (that's only for local people  ) didn't have the 12V/25mA bulb. So I bought a 12V/50mA lamp (screw version, no solderwires, but that's not big of a problem I think). Is this lamp useable for the NeoVibe circuit? Will it have effect on the sound? Do I have to make adjustments to the circuit? Or is it enough to just use the trimpot?

LDR: I bought 4 LDR05's. I can't find any datasheet of them. Can I use them? (they were expensive, 3,32 euro/pp) Maybe somenone has a datasheet of them? What should the specs be of the LDR's in the Neovibe?

Thanks...

[RaceDriver205]

Those parts sound fine, I used the same type of bulb and 4 'standard' LDRs and it sounded swell.

[jpm83]

I found this kind of specsheet. http://www.datasheets.org.uk/specsheet.php?part=LDR05

Janne

[carrejans]

I found this kind of specsheet. http://www.datasheets.org.uk/specsheet.php?part=LDR05

Janne

I found that one too. But the strange thing is; I found a few on the net, mostly in webshops, and they all have different values. 

[carrejans]

Anyone who could help me on this? 

[RaceDriver205]

What do you need help with? Just use those parts!

[carrejans]

What do you need help with? Just use those parts!

I wanted to know the specifications for the LDR's of the Uni/NeoVibe. I can't believe that it doesn't matter wich one you use.
But I think I will just try them then.
Thanks.

[RaceDriver205]

Well the design document doesn't state the type of LDRs because they tend to be roughly the same. You can tweak the brightness of the bulb afterwards with the trimmer resistor. You can of course put pin-sockets in place of the LDRs and then plug the LDRs into them, so you can swap them for others later if for some reason they don't work very well.
Good luck with the build, you won't be disappointed with the sound!

[R.G.]

Getting good LDRs is the hardest part of the Neovibe.

What you want is LDRs with an off resistance of 2M to 10M, an on resistance of about 2K, and high speed (for an LDR). As you might guess, given Murhpy's agreement with Mother Nature, the tricks you need to do to get high speed are in opposition to the tricks you'd play to get wide range and high off resistance, so it's tricky.

My best advice is the same as for other "magic" parts: use parts that you can actually get that are close, and remember over time to keep looking for the perfect ones. Put the perfect ones in later when you find them.

[carrejans]

Thanks for your replies guys.
So, this is the info I got for the LDR05:
- V(O) Max.(V) Output Voltage = 150
- Rlight Typ.(ohms) Light Rest. = 300
- @Ev (lx) (Test Condition) = 1.0k
- R(off) (ohms) Dark Resistance = 10M

So if I understand you right RG; the off resistance of these LDR's are good; but the on resistance is too low with its 300 ohms.
I don't know how you can know the speed of the LDR. I just have to try these, I guess.

RG, what about the lamp? Would the 50mA in stead of 25mA affect the sound? If so, in which way?

Thank you very much...

[R.G.]

No, 300 ohms light is just fine. It's unusual to find one that wide is all.

You're right - try it and see if it's fast enough. I could tell you how to test it, but you might as well test it in the unit.

The 50ma rating on the lamp just means that the lamp pulls more current at full voltage. In the vibe circuit, you don't really need full brightness. The only issue is that bigger currents cause more strain on the driver transistor and the power supply.

Again, the right thing to do is try it with what you can get, and if that works, great, you're done. If it kinda works or isn't very good, keep looking for the perfect thing. But you'll get all of your debugging done now and only have to replace the few parts that you find better examples of.

[carrejans]

No, 300 ohms light is just fine. It's unusual to find one that wide is all.

Well, they were quiet expensive too. 
About $4,5 each.

[R.G.]

Oouch! That hurts.

[dr]

......the ones I used for mine were the ones that come in those nightlights-bought a couple of two-packs at Big Lots, they work great!...