Opto Pot

[Colin Wonfor]

Here is a project I have been toying with for a while I am hoping to make available as a PCB/KIT soon. The best bit no nasty LDR' with the poison Cadmium, and you can set the range you want.

https://scontent-lhr8-1.xx.fbcdn.net/v/t1.0-9/91569300_2563577433960322_212022018344747008_o.jpg ?_nc_cat=110&_nc_sid=8024bb&_nc_oc=AQm3gPyp7aq8YxpEAUyrps-XIfDqj6RzCKdI9xgptfHEF3epgxk0GtTs0Pu2eWmxEy8&_nc_ht=scontent-lhr8-1.xx&oh=7c46d068a767c0dfc7e3f717ffb529bf&oe=5EAD21D1

[CageyH]

Interesting. How big is the PCB likely to be?

[Audio Al]

Did someone say-------- POT :smoking:

[Colin Wonfor]

This non SMD version is 87mm x 66mm 1.6mm thick.
I thought non SMD for first time DIYers is best. 0102 resistors a wee bit small.

[CageyH]

A good idea in my opinion.

[Puffin]

Hi Colin, I am interested in this. Any idea on price for the boards and the parts?

[Colin Wonfor]

Not yet sorry

[CageyH]

Please update this thread when you do have that information. :thumbsup:

[Light Dependant Resistor]

Here is a project I have been toying with for a while I am hoping to make available as a PCB/KIT soon. The best bit no nasty LDR' with the poison Cadmium, and you can set the range you want.

https://scontent-lhr8-1.xx.fbcdn.net/v/t1.0-9/91569300_2563577433960322_212022018344747008_o.jpg ?_nc_cat=110&_nc_sid=8024bb&_nc_oc=AQm3gPyp7aq8YxpEAUyrps-XIfDqj6RzCKdI9xgptfHEF3epgxk0GtTs0Pu2eWmxEy8&_nc_ht=scontent-lhr8-1.xx&oh=7c46d068a767c0dfc7e3f717ffb529bf&oe=5EAD21D1

You are confusing non encapsulated LDR's with entirely safe encapsulated audio types, do you understand and appreciate the difference of each type ?

[CageyH]

Cadmium is still nasty stuff though.

[Light Dependant Resistor]

Cadmium is still nasty stuff though.

I appreciate this is Colin's trade thread, and wish him success with using opto couplers in a attenuator circuit.

At the same time though it needs pointing out taking a cheap shot at LDR's " The best bit no nasty LDR' with the poison Cadmium "
would have been best left out of his first post, as encapsulated audio purpose LDR's are excellent for audio purposes, and represent no
public safety risk, which Colin very likely knows already.

[CageyH]

Agreed there is no public safety risk, as many people will have an LDR in their TV, but I still stand by my comment.

[Light Dependant Resistor]

Agreed there is no public safety risk, as many people will have an LDR in their TV, but I still stand by my comment.

Actually no TV's rarely have LDR's rather they use infra red communication , and points that an image of each type of LDR is needed to clarify.
I won't invade Colin's thread, but will attend to this with a proper explanation of each, in a separate thread. On a side note even the European Commission
was misled by Macron representing the wrong type, and the EU became aware of their error subsequently supported Silonex to give encapsulated types exemption.
I covered this many years ago in a thread. But here is the wording from the European Commission

"Dear Mr Daly,

Thank you for your message.

The Commission Directive 2012/51/EU has enabled the use of cadmium in photoresistors for analogue optocouplers as an exemption from the ROHS directive. Therefore, indeed, the use of cadmium in photoresistors for analogue optocouplers is currently allowed as there are no other substitutes. We draw your attention in this context to the recitals of the Directive:
http://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1403091086794&uri=CELEX:32012L0051

This new delegated Directive is based on the Recast of the RoHS Directive which entered into force in January 2013. The information relating to the recast of this Directive with the comments submitted during the public consultation is available on the following website of the Directorate-General for the Environment:
http://ec.europa.eu/environment/waste/rohs_eee/index_en.htm

If you wish to voice your opinion on waste management issues and changes to the EU legislation, we invite you to consult the public consultations webpage on DG Environment:
http://ec.europa.eu/environment/consultations_en.htm

We hope you find this information useful. Please contact us again if you have other questions.

With kind regards,
EUROPE DIRECT Contact Centre
http://europa.eu - your shortcut to the EU!

[Colin Wonfor]

And in a fire what happens to the plastic coating and the Cadmium Vapour ? Not for me, no thanks I have seen this shit stuff poison folk not good at all,It is still band in consumer products for me.

I suspect this has changed as Crydom's SSR's failed the EMC and RFI regs but because they are a massive company paid to have the rules changed, money talks. The last I heard was Cd can only be used on MIL spec kit, but not for me sorry.

[Colin Wonfor]

I appreciate this is Colin's trade thread, and wish him success with using opto couplers in a attenuator circuit.

At the same time though it needs pointing out taking a cheap shot at LDR's " The best bit no nasty LDR' with the poison Cadmium "
would have been best left out of his first post, as encapsulated audio purpose LDR's are excellent for audio purposes, and represent no
public safety risk, which Colin very likely knows already.


I am sorry that my comment and view upset you, but I will never use them in a product that can be tampered with burn smashed and ruin people health. Next we will use Uranium in Shells oh we do . so no thanks.

[Light Dependant Resistor]

I am sorry that my comment and view upset you, but I will never use them in a product that can be tampered with burn smashed and ruin people health. Next we will use Uranium in Shells oh we do . so no thanks.

You sadly have got off on the wrong foot creating, and I see from your comments above, continuing sadly fanciful misinformation, about products that you appear to know very little about.
I suggest it might be better, to take your time, and learn to appreciate every product that has benefit for audio reproduction. They all have some unique applications, that
can assist the reproduction of audio we enjoy.

So change of shoe, please. Have you a working model of your circuit, have you connected it to a audio system ?

[Colin Wonfor]

Be safe.
Yes works fine on third attempt. I hate vero board.

https://en.wikipedia.org/wiki/Cadmium_poisoning

[Light Dependant Resistor]

What attenuation range, are you achieving - resistance Min to maximum ? , and do you have good audio reproduction already, or are there refinements needed.

[CageyH]

Actually no TV's rarely have LDR's rather they use infra red communication , and points that an image of each type of LDR is needed to clarify.
I won't invade Colin's thread, but will attend to this with a proper explanation of each, in a separate thread. On a side note even the European Commission
was misled by Macron representing the wrong type, and the EU became aware of their error subsequently supported Silonex to give encapsulated types exemption.
I covered this many years ago in a thread. But here is the wording from the European Commission

"Dear Mr Daly,

Thank you for your message.

The Commission Directive 2012/51/EU has enabled the use of cadmium in photoresistors for analogue optocouplers as an exemption from the ROHS directive. Therefore, indeed, the use of cadmium in photoresistors for analogue optocouplers is currently allowed as there are no other substitutes. We draw your attention in this context to the recitals of the Directive:
http://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1403091086794&uri=CELEX:32012L0051

This new delegated Directive is based on the Recast of the RoHS Directive which entered into force in January 2013. The information relating to the recast of this Directive with the comments submitted during the public consultation is available on the following website of the Directorate-General for the Environment:
http://ec.europa.eu/environment/waste/rohs_eee/index_en.htm

If you wish to voice your opinion on waste management issues and changes to the EU legislation, we invite you to consult the public consultations webpage on DG Environment:
http://ec.europa.eu/environment/consultations_en.htm

We hope you find this information useful. Please contact us again if you have other questions.

With kind regards,
EUROPE DIRECT Contact Centre
http://europa.eu - your shortcut to the EU!

A lot of TVs have an LDR for auto-calibration of the image brightness.

Here is a document from 2013 on Cadmium.
https://echa.europa.eu/documents/10162/23665416/support_document_cadmium_20130612_11565_en.pdf/cfbe4f43-8764-29f9-103b-8cf544dd4c02

My personal choice is to avoid cadmium containing devices where there is a practical alternative, but everybody is free to make their own choices.

[Colin Wonfor]

What attenuation range, are you achieving - resistance Min to maximum ? , and do you have good audio reproduction already, or are there refinements needed.

1R - 100MR refinement to come once I get proto type pcb the BW is also good over 10MHz but I think it could be better, and I may use it is mixer I am making.

[Light Dependant Resistor]

A lot of TVs have an LDR for auto-calibration of the image brightness.

Here is a document from 2013 on Cadmium.
https://echa.europa.eu/documents/10162/23665416/support_document_cadmium_20130612_11565_en.pdf/cfbe4f43-8764-29f9-103b-8cf544dd4c02

My personal choice is to avoid cadmium containing devices where there is a practical alternative, but everybody is free to make their own choices.

But where entirely safe to use, https://lunainc.com/product/optocouplers/
as is the case with encapsulated types why deny yourself a better audio experience ? I think we are going round in circles.
I would like to know what Colin has achieved,

[CageyH]

It won’t be a better audio experience. My pre amp has my phonomstage built in.
Vinyl will sound pretty poor with out a suitable device in the chain.

[croak]

Following with interest.


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