ASDA £2.93 webcam

[Chris]

Starfox - you have to be careful where you copy and paste your information from, as some of the info on the web is out of date and some just completely wrong.

CMOS image senors actually use photodiodes to convert the photons not transistors, modern CMOS sensors also use some sort of gapless microlenses located above each photodiode, to maximise the light gathering capability no matter what angle the light arrives at the sensor from.

Auntystatic- If each photodiode has its own lense which picks up light no matter what angle the light arrives at the sensor how would this form an image that represents reality? I was always taught that only incident photons will form an accurate image, and in my day job we go to great lengths to assure that only incident photons reach the image sensor. I work with high energy photons and above 70kV they evoke Compton scattering when interacting with matter and therefore ping off atoms in all directions, thus we have to use a lead grid which only allows incident photons to pass through in order to form an image. I have tried not using a grid above 70kV and the image is very poor so I've done the practical on this subject not just the theory. Could I have a link to where you got your info from please:)

[SwampStar]

2 ASDAcams arrived last night courtesy of me dear old dad...he's in ASDA a lot more than I am!

Going to have a look back through the thread for the necessary mods...never done this before. Scary stuff!

Some great posts, though.

[c3po]

2 ASDAcams arrived last night courtesy of me dear old dad...he's in ASDA a lot more than I am!

Going to have a look back through the thread for the necessary mods...never done this before. Scary stuff!

Some great posts, though.

According to FLOs website my £10 nose piece adaptor should be here tomorrow, if it fits i'll get photos uploaded and share the knowledge!

Now then, on another subject withe the ASDACam, anyone fancy trying a peltier cooled version?..... where's Cliff or Gina when we need them!?

[Dodge]

Just picked up a couple of these from Basingstoke branch, who had another 6 on the shelf if anyone's interested.

[Dodge]

According to FLOs website my £10 nose piece adaptor should be here tomorrow, if it fits i'll get photos uploaded and share the knowledge!

If it's the SPC900 one then it won't unfortunately.

[c3po]

If it's the SPC900 one then it won't unfortunately.

ahhh, it was this one i ordered.

what's the problem, wrong thread or too small a hole in the case? if the latter, that's easily rectified with a Dremel fitted with a fine sanding bit

[cgarry]

Auntystatic- If each photodiode has its own lense which picks up light no matter what angle the light arrives at the sensor how would this form an image that represents reality? I was always taught that only incident photons will form an accurate image, and in my day job we go to great lengths to assure that only incident photons reach the image sensor. I work with high energy photons and above 70kV they evoke Compton scattering when interacting with matter and therefore ping off atoms in all directions, thus we have to use a lead grid which only allows incident photons to pass through in order to form an image. I have tried not using a grid above 70kV and the image is very poor so I've done the practical on this subject not just the theory. Could I have a link to where you got your info from please:)

Microlenses Explained | Technology guides | Techniques | What Digital Camera

This is pretty standard technology for CMOS sensors these days.

Cheers,

Chris

[Dodge]

ahhh, it was this one i ordered.

what's the problem, wrong thread or too small a hole in the case? if the latter, that's easily rectified with a Dremel fitted with a fine sanding bit

Well, both actually! The threaded lens holder is quite a bit smaller than the SPC900 thread - see the attached pic.

[russellhq]

Maybe you could swap the thread on the camera for the one I posted earlier (might have to glue it on though). It's design will fit the thread on the SPC900 as they are both M12 x 0.5mm

[c3po]

Well, both actually! The threaded lens holder is quite a bit smaller than the SPC900 thread - see the attached pic.

without trying to upset the forum swear filter, what i'm about to say won't even begin to cover what i really want to say; DARN & BLAST!

Oh well, back to the drawing board i guess... i have a Logitech QuickCam that the adaptor should fit, and have an xbox cam on the way too. I don't think i could accurately position the other thread adaptor centrally enough on the sensor to justify attempting it, shame really.

[Dodge]

without trying to upset the forum swear filter, what i'm about to say won't even begin to cover what i really want to say; DARN & BLAST!

Oh well, back to the drawing board i guess... i have a Logitech QuickCam that the adaptor should fit, and have an xbox cam on the way too. I don't think i could accurately position the other thread adaptor centrally enough on the sensor to justify attempting it, shame really.

Yeah, I'm going to wait until someone clever comes up with the correctly threaded adapter. I'm not that person.

[c3po]

Yeah, I'm going to wait until someone clever comes up with the correctly threaded adapter. I'm not that person.

what dimensions are the thread on the ASDAcam? i know of a couple of places to look... closest millimetre should do.

[JamesF]

That's almost wilfully obtuse, using a different mount from almost everyone else. I wonder what the higher-resolution camera uses?

Anyhow, the SPC900 nosepiece does definitely fit the Xbox camera, so you will be able to use it for that.

James

[Dodge]

what dimensions are the thread on the ASDAcam? i know of a couple of places to look... closest millimetre should do.

~7 mm.

[Auntystatic]

Star fox - I didn't reply to your last message as I didn't want this to turn in to a flame.

Try this link it shows in pictures what microlenses are.

I was always taught that only incident photons will form an accurate image

Yep and we are talking about light that comes down a narrow telescope tube of some sort, not from 90deg.

I work with high energy photons and above 70kV they evoke Compton scattering when interacting with matter and therefore ping off atoms in all directions

Lets keep this real we are talking about webcams here!

When I was young I used to play with 100kW transmitters, oh the joy of watching the lightning dance around a 600ft aerial, then the deafening bells from the transmitter going down as it finally struck, I wonder if the hunch in my back is because of those damn bells, I wonder how many kV was in the lightning, my cars ignition coil puts out around 20kV and that hurts when it bites.

And lens doesn't have an "e" on the end unless followed by an "s" sorry pet hate of mine that one

P.s some great images coming on here from a resourceful bunch.

[JimFR]

what dimensions are the thread on the ASDAcam? i know of a couple of places to look... closest millimetre should do.

I had some similar trubbs when I bought for 20 quid (20 quid !!) a Logitech Quickcam E3500 for this purpose (about 3 years ago) which turned out to be cack for what webcams are for anyway - I ordered a nosepiece from Scopes'n'skies, but it seems the 'lens' holder was considerably smaller - my guess is it was an M10, not an M12. still, the adaptor came in handy when I got the boardcam

[russellhq]

What's the distance between the screws on the ASDA cam? Surely it would be cheaper to get a new lens holder for a couple quid than to make a nose piece designed specially to fit??

[JamesF]

It's hard to tell from nytecam's images, but I'm not sure there'd be enough space on the PCB. As I happen to have an Xbox camera open here on my desk I just measured the centres for the screws at about 18mm (best I can do without a pair of calipers at the moment). The base of the lens mount is about 15mm square excluding the lugs for the screws.

If there's 15mm clear space around the sensor, perhaps an S mount with the lugs cut off and glued to the face of the PCB would work?

James

[Chris]

cgary- thanks for the link it was very useful, so basically there are issues with steep angles of light being refracted by the lenses onto the wrong part of the sensor or hitting no part of the sensor at all, but these are accepted issues that do effect the image but they obviously don't effect the image as much as I thought they might.

Cheers,

Chris:)

[Chris]

Auntystatic- thanks for the link, if you get the chance have a look at cgary's link its very good.

- I didn't reply to your last message as I didn't want this to turn in to a flame.

Uhh?

-Lets keep this real we are talking about webcams here!

I used an analogy, I thought it was ok to do this?

-And lens doesn't have an "e" on the end unless followed by an "s" sorry pet hate of mine that one

I do spell things incorrectly sometimes.

[nytecam]

Another batch of images tonight through cloud gaps - it was amazing tweaking scope paddle to zoom across the moon in close-up like an Apollo Craft of old. Capture via excellent SharpCap with much better image control of brightness/gain and exposure etc then quickie pass through Registax - Mars very bright at f/10

Note the dual crater Messier [top right] with lighter splash material across maria like a comet's tail. Getting slightly better with Mars - Cartes du Ciel Mars for date/time comparison

ps: I coupled Asdacam to 1-1/4" scope adapter with a big ring of Blutak eg quick and dirty but works for now as pics demo

[jeremy1]

Good Piccys there from Asda Cam. Just goes to show what can be achieved on a small budget.

[NickK]

Serious competition considering the price to DMK and other manufacturers!

[c3po]

EUREKA!!!!

The ASDAcam + FLO SPC9000 'scope adaptor modification is complete!

Firstly,as reported earlier, the SPC 900 adaptor does not fit out of the box. I can also confirm that the screw-in thread of the ASDAcam is approx. 7mm inner-diameter and it's outer diameter is around 9mm here's a close up of the camera lens fitting.

You can clearly see that the ASDAcam thread is FAR too small for the M12 thread of the webcam adaptor, however, what i did notice was how close the adaptor was to allow a push fitting over the outer section of the threaded section on the webcam.

So, i dragged out my Dremel and a round file bit and for about 10 minutes slowly ground away at the inside of the FLO webcam adaptor (it's a plastic material - Delrin??) just enough to allow a push-fit over the original web cam lens fitting. I would estimate probably less than ~0.75mm was required to be removed, certainly no more. Here's a close up of the SPC adaptor and where to grind...

With the attachment of the adaptor done, i turned my attention to the front cover - the hole is too small by too big a margin (approx 2-3mm) to grind it out with the Dremel. Then i noticed something, the ASDAcam's front cover is actually two pieces laminated together with double-sided tape!

I carefully prised them apart with a thin jewellers flat-head screwdriver, screwed the unit it back together and confirmed it fit by push-fitting the SPC900 adaptor right over the top - worked a treat, and not only can i now use an IR/UV filter on the adaptor, but i still have the thread intact to use on another (M12 compatible) webcam in the future!

and here it is, all together and ready for 1st light!

[Chris]

really nice end result c3po, I really must get a Dremel at some point, good look with first light I'm still waiting for 1st light myself.