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Webcam Mod wiring

malc-c

By malc-c
in DIY Astronomer

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mrmoo

mrmoo

Posted
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You just want to keep the ccd as cool as you can to reduce noise. A fan at least stops the case temperature rising. Easy to check the function of the circuit, when switching from standard mode to LX make sure 5vdc is appearing on the RTS/DTR diodes. After that check the zener goes low from 15.4vdc to around 11vdc and the 8/13 transistor base goes from 3.3vdc to zero.

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leenewtoastro

leenewtoastro

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errmmm no tbe. i found no faults with the mod!

i tried it with the case open and the mod board/components remained stone cold however the lower board and to some degree the top biggish square chip had some "warmth"

when all refitted after 10mins the case would be "luke"

will have to try without holding it stop any heat transfer from hand holding it being a factor.

short of returning it to std op to gauge std heat will be a blow.

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leenewtoastro

leenewtoastro

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just to double check i disconnected the mod and put the connections back. same heat. so thats normal. but. i noticed if i put the camera upto a bright light like out of a window i get these streaks. if i adjust gain or exposure they will reduce but then the image is too bright too dull! normal?

streaks.jpg

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malc-c

malc-c

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Try using SharpCap - I don't have the link to hand - but there is a video done by Astronomy shed on youtube showing the settings - I found it was less jumpy than using the wxastro - and the picture quality was a lot better !

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leenewtoastro

leenewtoastro

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malc, when you said don't connect 5v did you mean from the serial? or from the cam board or both? don't think i have this working.

are you testing LE with the std lens so you can view something?

and what should happen in preview? still frame for the exposure time set?

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malc-c

malc-c

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Hi,

Yes... your sketch showed the red wire of the serial cable connected to the +5v from the USB. The serial cable just needs the RTS, DTR and GND lines. The transistor board does need the 5v supply from the camera PCB - seems you now have that sussed

Yes - last night I used the camera in a room illuminated with nothing more than the street light glow coming in from the frosted window in the front porch - looked like the sun was streaming in, and that was only with around 1s exposure !

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malc-c

malc-c

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Came home rather miffed... sky was clearing and I had to go out :p

However by 7:45pm I managed to get everything done and return home and by around 8pm had the scope set up which was a bit of a record as it normally takes me 5 trips up and down the stairs !

By this time seeing was poor. The sky was light and light pollution didn't help. However I did manage to try out the modded web cam on the Orion Nebular.

1st problem... focusing. The depth of field was so narrow and with such a poor atmosphere (plus Orion was over the house which given how warm it was today and this evening which didn't help) the focus was hard to achieve. 2nd, I had no idea what I really was doing or how capturing long exposures worked... but here are two images. One is a single frame which I've simply tweaked the curves. The other is a result of stacking all 8 frames of the capture and then the result also tweaked in PS. They are not brilliant by a long shot... but at least it proves the modification worked :D

post-23388-133877551298_thumb.png

post-23388-133877551321_thumb.png

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malc-c

malc-c

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i think they are brill. can't wait to dabble myself :D

post the settings notepad malc if you wouldn't mind

Thanks,

I think these are the settings for the images


[Philips SPC 900NC PC Camera (LX Mode)]
Brightness=64
Contrast=32
Saturation=0
Gamma=21
ColorEnable=255
BacklightCompensation=25
Gain=3
LXExposure=20.0Resolution=640x480
Frame Rate (fps)=10.00
Colour Space / Compression=YUY2
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malc-c

malc-c

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Received another SPC880 yesterday as I'm not really happy with the original. It's too big and bulky and as I super-glued the 1st camera thought I would get a spare just in case it broke when I tried to remove it.

Anyway, whilst I've been involved in electronics for ages and have built some elaborate projects, my eyesight over the past year or so means I can't do small close work to make a board small enough to fit inside the casing like Lee has. I'm therefore considering using a 7 core screened cable to take the wires from the connector, supply and regulator in the camera to a box containing the PCB, and then back to the camera... This would give me a longer cable from the scope to the netbook, and only a single cable coming out of the camera, which would be in it's original housing. Something like the attached - comments please

post-23388-133877552373_thumb.jpg

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leenewtoastro

leenewtoastro

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i had (honestly) concidered very similar.

i was going to still house my pcb in the cam as i have, but change the cable to accommdate the number of wires needed in one then split the cable at the plug end for usb and serial .

not sure if any sreening would have been needed and that may add to the overall diameter of cable/weight.

but yes should be nice Malc.

my only other slight regret for perfection is i should have made the cables side entry so it would look neater in the focuser without a "loop" of cable :D

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malc-c

malc-c

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I'll pop into Maplin in the morning and see if they have some suitable multi-core cable. I did look at using a 3M cat5 cable, but it's very stiff and not really ideal. As packet data is being sent along some of the wires I think I'll opt for screened cable if I can find some.

Hey you've done an excellent job. I wish I could reduce the board down to fit inside the stock camera.... My "concern" is that with the current length of cables, there is a weight that hangs down on the scope which I want to reduce, and with the goto it isn't long enough to go through its slewing motion without pulling the netbook off it's table.

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nightvision

nightvision

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Thanks for the links :D, some neat work going here, inspired me to get mine finished.

I recently picked up an original 900NC, came across an old box covered in dust at a Maplin store.

I will be doing the mods but using it as a guide-cam. I have some old telephoto lenses which I am experimenting with, trying focal reduction to increase brightness of guide star.

Also experimenting with an offset 114mm F9 mirror and reducer as a guide scope.

Tony.

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malc-c

malc-c

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I've just spent an hour or so re-boxing my converted web cam - it was a tight fit and due to the central screw pillar being just a gnats **** in the wrong place had to super-glue the case together after shoehorning my board in... but it's a vast improvement on the 1st attempt. - Might even spray the box with some Matt paint later.

I've also picked up 4M of 8 core alarm cable, a small box and a chassis mount serial connector to test out my idea of a single cable from the camera, but at the moment it will have to wait as I need to sort out a few things for SGL6 next week.

post-23388-133877552725_thumb.jpg

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