Author Topic: CdS photocell in a biscuit tin  (Read 2147 times)

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Offline fcbTopic starter

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CdS photocell in a biscuit tin
« on: December 20, 2017, 10:35:46 pm »
Picked up a tin of biscuits from Sainsbury’s supermarket today.

It has a voice record/playback feature - triggered by a CdS photocell built into the lid.

There’s the non-recycling logo and a warning about not eating the button cell, but no RoHS or CE marking.

Am I right in thinking that CdS photocells are incompatible with RoHS/CE/WEEE??
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Offline T3sl4co1l

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Re: CdS photocell in a biscuit tin
« Reply #1 on: December 20, 2017, 11:19:36 pm »
CdS cells did not get an exemption, I suppose on account of alternatives being better anyway (silicon or photodiode detectors).

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Offline rrinker

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Re: CdS photocell in a biscuit tin
« Reply #2 on: December 22, 2017, 03:38:30 am »
 Funny, I just happened to watch Techmoan's NUC video last night and heard the chime when he opened the box. Hadn't seen that before - I ALMOST went with one for my workbench computer because I wanted small to save as much space as possible, but I ended up building a mini-ITX cube because it was significantly less expensive. ANd I can put it under, if I need to, but it's pushed back in the mostly unusable corner anyway.

 

Offline Halcyon

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Re: CdS photocell in a biscuit tin
« Reply #3 on: December 22, 2017, 07:02:32 am »
And for what is worth, Intel NUC boxes (pre-Skylake) also have a music chip that plays Intel chime when the box is opened. It's also light triggered, though I don't know what sensor it used.

Aww ripped off! Mine was just a boring cardboard box! It's about a year old however.
 

Offline Ampera

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Re: CdS photocell in a biscuit tin
« Reply #4 on: December 22, 2017, 07:04:28 am »
are the biscuits any good though?
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Offline jonovid

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Re: CdS photocell in a biscuit tin
« Reply #5 on: December 22, 2017, 07:15:00 am »
aliexpress has this .
just the thing for toys or door bell ....esc
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Offline Zero999

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Re: CdS photocell in a biscuit tin
« Reply #6 on: December 22, 2017, 09:09:26 am »
Picked up a tin of biscuits from Sainsbury’s supermarket today.

It has a voice record/playback feature - triggered by a CdS photocell built into the lid.

There’s the non-recycling logo and a warning about not eating the button cell, but no RoHS or CE marking.

Am I right in thinking that CdS photocells are incompatible with RoHS/CE/WEEE??
Do you have any pictures?

Are you sure it's a CdS cell?

Perhaps it's so small, compared to the mass of box, it passes RoHS?
 

Offline fcbTopic starter

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Re: CdS photocell in a biscuit tin
« Reply #7 on: December 22, 2017, 01:59:45 pm »
Picked up a tin of biscuits from Sainsbury’s supermarket today.

It has a voice record/playback feature - triggered by a CdS photocell built into the lid.

There’s the non-recycling logo and a warning about not eating the button cell, but no RoHS or CE marking.

Am I right in thinking that CdS photocells are incompatible with RoHS/CE/WEEE??
Do you have any pictures?

Are you sure it's a CdS cell?

Perhaps it's so small, compared to the mass of box, it passes RoHS?

https://www.sainsburys.co.uk/shop/gb/groceries/sainsburys-cookie-envelope-christmas-tin--taste-the-difference-400g

I'll take some pix tonight, and strip down the electronics.

It looks very much like a CdS photocell, so I'm fully expecting it to be one.

A number of years ago I wanted to go into production with a musical instrument product that used 8 photocells - couldn't use photo-diodes, they had to be photo-resistors.  I did loads of research into them to try and find a RoHS compliant - I looked at using the Cd weight vs. the overall weight of the product, but that apparently doesn't stand (if my memory serves) - something to do with a CdS cell not being homogeneous material.

There were some exemptions made for a number of years for the audio industry (vactrols, used in level control), but these have stopped I believe:
http://rohs.exemptions.oeko.info/fileadmin/user_upload/RoHS_IV/Cons_1/Excerpt_report_2007_request_1.pdf

Silonex are now: http://lunainc.com, and they still sell vactrols "optocouplers", but no mention of RoHS compliance.
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Offline Zero999

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Re: CdS photocell in a biscuit tin
« Reply #8 on: December 22, 2017, 09:17:55 pm »
If it's a CdS cell, then it's probably not RoSH compliant.

Have you tested the recoding and playback? It's had mixed reviews, according to the Sainsbury's website.

Just out of curiosity, why did you need CdS cells, rather than photodiodes? I didn't find Marshell's argument for CdS cells very convincing. They mention things such as 64-bit DSP, which is boarding on audiophoolery and their comment about weight and power consumption is a joke, when replacing heavy, power hungry valves and massive transformers, with DSP would  reap huge savings in mass and energy. There are plenty of decent, low power, analogue based, automatic gain control ICs available. I think they're resistant to change, like many audio equipment designers.
 


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