LDRs for Harbinger2

[pt67]

I'm about to embark on the Harbinger 2 project, but I'm having trouble locating the recommended LDRs. I have acquired some GL5549s at a very reasonable price and I'm looking for some insight as to whether I can make them work or not. They have a resistance of 100k - 200k light and 10M dark. Would I need to alter any other resistor value or other components to create the desired Univibe effect? Thanks for your help.

[mauman]

Welcome to the forum!

The difference between the recommended LDRs and the ones you have on hand are the minimum resistance when the light is the brightest.  The NSL-7532 should have a minimum between 500 ohms and 10k ohms, and the 9302 should be between 5k and 20k ohms.  Your GL-5549 have a minimum between 100k and 200k, which is about 10 times the others.  These will work, but will have less of an audible "notch" when the lamp is brightest. 

One way to mitigate the difference is to leave the legs on the LDRs long enough to stand them up, even with the lamp filament.  Bend the LDR faces 90 degrees to point directly at the lamp.  Then bend them inward to almost touch the lamp.  Here are two examples of that, on two different boards similar to the Harbinger. 

[pt67]

Thank you so much. I'll post my results!!

[pt67]

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[jessenator]

BTW, if you know anywhere these are sold, I could a clue.

Small Bear had some of the NSL-7532, but sadly they're out of stock. I struggled to find some for my Harbinger 1.5, and up until Small Bear came back to selling parts I couldn't find those anywhere else, on any continent  : /

[pt67]

I found these... see attachment

[mauman]

You could socket the ones you have, and if you don't like them, replace them with these.

[jessenator]

I found these... see attachment

Nice! Glad to see they're out there.