Modifying the exposure time of a CCD video camera?

[NightRunner]

Hello all,

I have been reading a lot lately about CCD astrophotography, and
noticed a few mentions of modifying a CCD video camera for longer
exposure times via replacement of a resistor or what have you...

I have two CCD surveillance cameras; a Lorex 2.4GHz wireless BW
camera, and a Remmington 00821-col color bullet style camera. The
Remmington I would rather NOT fool with modifying unless it is simple
and easily manageable. The Lorex, however, has already been through
two lifetimes worth of serious abuse and I have no real qualms about
really making it suffer, hehehe.

So anyways, can anyone point me in the right starting direction to
modify the exposure time for this sort of camera? If neccessary I can
take extreme closeup pictures of both sides of the imaging board and
provide any chip numbers and the model number of the camera itself.

Thanks!

- NR




"The usual approach of science of constructing a mathematical
model cannot answer the questions of why there should be a
universe for the model to describe. Why does the universe go
to all the bother of existing?"

- Stephen Hawking

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[Fred]

Hello all,

I have been reading a lot lately about CCD astrophotography, and
noticed a few mentions of modifying a CCD video camera for longer
exposure times via replacement of a resistor or what have you...

I have two CCD surveillance cameras; a Lorex 2.4GHz wireless BW
camera, and a Remmington 00821-col color bullet style camera. The
Remmington I would rather NOT fool with modifying unless it is simple
and easily manageable. The Lorex, however, has already been through
two lifetimes worth of serious abuse and I have no real qualms about
really making it suffer, hehehe.

So anyways, can anyone point me in the right starting direction to
modify the exposure time for this sort of camera? If neccessary I can
take extreme closeup pictures of both sides of the imaging board and
provide any chip numbers and the model number of the camera itself.

Thanks!

- NR

I may suggest that the crystal frequency driving the camera circuitry is
reduced - assuming 1 crystal. This will of course give you a non-standard
video output. I assume the camera is B/W?

 

[NightRunner]

Yes, the Lorex is BW and has a nice, simple board layout for the video
unit. Looking closely, the crystal is on the front face of the board,
and is marked:

88BT

Hmmm... Anyone know based on that who made this crystal and what
frequency it is?

- NR

I may suggest that the crystal frequency driving the camera circuitry is
reduced - assuming 1 crystal. This will of course give you a non-standard
video output. I assume the camera is B/W?

"The usual approach of science of constructing a mathematical
model cannot answer the questions of why there should be a
universe for the model to describe. Why does the universe go
to all the bother of existing?"

- Stephen Hawking

---------------------------------------
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http://niter417.virtualave.net/

Message Boards Main:
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Electronics Discussion:
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Our Webcam:
http://web.infoave.net/~missy1/cam/webcam.html

 

[Fred]

Yes, the Lorex is BW and has a nice, simple board layout for the video
unit. Looking closely, the crystal is on the front face of the board,
and is marked:

88BT

Hmmm... Anyone know based on that who made this crystal and what
frequency it is?

- NR

Haven't a clue. Have a look at some IC numbers on this board and have a
look at their datasheets.