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Equipment Discussions >> Electronically Assisted Astronomy

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ccs_hello
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LNtech 300 shrink down & wired remote control
      #5424442 - 09/16/12 09:35 PM Attachment (129 downloads)

Hi,

Just got the LNtech LN300R 960H NTSC video cam. This toy is using Exview HAD II type-1/3" ICX672AKA CCD.

Here is the inside on the main board.

There are 3 cords connect to the back board.
4 PIN cable: it's for lens control. For practical purpose it's not useful in our field. It will be removed.

3 PIN cable: 12V Power (RED), Ground (BLACK), and RS170A Video out (YELLOW).

2 PIN cable: to handle top-down-left-right-center buttons, using resistor matrix. <-- Black-White cord

Some interesting circuit observations:
1) 2-wire control (I'll show a DIY, posts #4-#11). No need to bother RS485 type of control.
2) RJ-11 DSP/CPU is used
3) AD9943 10-bit A/D AFE
4) JRC's NJM2274 (Y + C combiner) to form composite video output. In another word, this camera can send out S-video, if a slight change is made.
5) probably 74AC07 (JRC again) to drive lens-drive signals
6) IR-cut output (to drive a solenoid to mechanically move-in/move-out IR-cut filter) is unpopulated and is optional.

In post #12, I'll describe my general observations on its image accumulation part of design and software-based image summing.

Clear Skies!

ccs_hello


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ccs_hello
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Re: LNtech 300 shrink down new [Re: ccs_hello]
      #5424450 - 09/16/12 09:39 PM Attachment (82 downloads)

Here is the cable you can find for board camera. I happend to have one. Black jack is for 12V power. Yellow is the coax video out.

Clear Skies!

ccs_hello


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ccs_hello
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Re: LNtech 300 shrink down new [Re: ccs_hello]
      #5424451 - 09/16/12 09:40 PM Attachment (80 downloads)

Does this cam look smaller?
(Still have to handle the 5 buttons...)


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ccs_hello
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Re: LNtech 300 shrink down new [Re: ccs_hello]
      #5424460 - 09/16/12 09:44 PM Attachment (79 downloads)

Remote control handbox

- project box
- 5 push button switches
- 4 resistors

15KOhm (Top)
27KOhm (Right)
56KOhm (Bottom)
6.8KOhm (Center) i.e., 6k8
0 Ohm for (Left) i.e., no resistor required


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ccs_hello
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Re: LNtech 300 shrink down new [Re: ccs_hello]
      #5424463 - 09/16/12 09:46 PM Attachment (57 downloads)

Push-button switches mounted

Left is "Top" switch.


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ccs_hello
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Re: LNtech 300 shrink down new [Re: ccs_hello]
      #5424469 - 09/16/12 09:48 PM Attachment (50 downloads)

5 switches share the common contact. This is one of the 2 leads used for that (Black-White cable).

Left side is "Bottom" push button.
Bottom side is "Left" push button.


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ccs_hello
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Re: LNtech 300 shrink down new [Re: ccs_hello]
      #5424471 - 09/16/12 09:50 PM Attachment (61 downloads)

Now with 4 resistors and one "jumper wire" soldered in into one single junction.
They (4 resistors and one direct-wire) form the other lead for the two-wire control cable.

The mounting method is "fly wiring", a vacuum tube era technique .


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ccs_hello
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Re: LNtech 300 shrink down new [Re: ccs_hello]
      #5424475 - 09/16/12 09:52 PM Attachment (49 downloads)

The control wires (2 of them) are soldered and coming out from the bottom side of the box.

The control box is done.

Clear Skies!

ccs_hello


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ccs_hello
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Re: LNtech 300 shrink down new [Re: ccs_hello]
      #5424480 - 09/16/12 09:55 PM Attachment (77 downloads)

End result
(3 pictures)

The coupling is a 2" with a focal reducer built-in.
(My previous project, described here in CN.)

Clear Skies!

ccs_hello


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ccs_hello
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Re: LNtech 300 shrink down new [Re: ccs_hello]
      #5424482 - 09/16/12 09:56 PM Attachment (47 downloads)

The BLACK-WHITE cord connects to the 2-wires comming out of the control box.

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ccs_hello
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Re: LNtech 300 shrink down new [Re: ccs_hello]
      #5424484 - 09/16/12 09:57 PM Attachment (52 downloads)

Side view.

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ccs_hello
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Re: LNtech 300 shrink down new [Re: ccs_hello]
      #5424578 - 09/16/12 11:04 PM

Now on the camera's behavior:

As expected, this cam is tuned mostly for automated operation without human intervention. In another word, have to try hard to defeat camera's CPU making decision and override your input.

Another thing is that this camera takes time to initialize, also the picture update cam be long, after the image is acquired. I.e., Do not expect immediate display when an image acquisition period ends.

If need to have a predictable result, do not use any setting starts with "A", e.g., AGC. (Automatic Gain Control.)
Actually SENSE-UP is too smart (cam does thing other than your input on that field's setting).

AGC is rather crazy, in addition to signal gain, on as needed basis, it will also do software image summing.

The SENSE-UP in this camera's design is also software image summing.

The only one that does image accumulation (true long exposure) is the ELECTRIC-LENS setting (up to 1024x).
But in this setting, do not turn on AGC. It will once again messing up the long exposure.

Clear Skies!

ccs_hello


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Whichwayisnorth
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Re: LNtech 300 shrink down new [Re: ccs_hello]
      #5425464 - 09/17/12 01:36 PM

I have the same camera and I just wanted to say thank you so much for this thread. I need to duplicate your control box.

Please keep us updated on what you discover. I only had the camera out one night and it seemed to work well.


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Teabagger
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Reged: 08/18/12

Re: LNtech 300 shrink down new [Re: Whichwayisnorth]
      #5425733 - 09/17/12 03:54 PM

disregard


Edited by Teabagger (09/17/12 03:56 PM)


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James Cunningham
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Re: LNtech 300 shrink down new [Re: Whichwayisnorth]
      #5426800 - 09/18/12 07:09 AM Attachment (64 downloads)

I just got an e-mail from Jock who sells these cameras. He sent me 2 photos of a remote control cable. Here they are:

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James Cunningham
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Re: LNtech 300 shrink down new [Re: James Cunningham]
      #5426802 - 09/18/12 07:10 AM Attachment (42 downloads)

Here is the other one:

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ccs_hello
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Re: LNtech 300 shrink down new [Re: James Cunningham]
      #5426899 - 09/18/12 08:40 AM

Jimmy

The cable set is cables only.
The board you've shown is not LN300.

The cable would work but IMHO is overkill for LN300R.

Clear Skies!

ccs_hello


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barbarosa
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Reged: 04/11/10

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Re: LNtech 300 shrink down & wired remote control new [Re: ccs_hello]
      #5427617 - 09/18/12 03:14 PM

Quote:

Hi,

4) JRC's NJM2274 (Y + C combiner) to form composite video output. In another word, this camera can send out S-video, if a slight change is made.

ccs_hello





The S-video out possibility is really interesting. You can bet that I will follow this thread closely.


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ccs_hello
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Re: LNtech 300 shrink down new [Re: ccs_hello]
      #5427942 - 09/18/12 05:59 PM

Example of this cable (post #2) can be found in fleabay linkie or search there keyword "BNC DC Power Jack to 3 Pin Connector Cable".
$2 shipped to US. Good price!

Note: I have not seen the actual cable so I am just guessing. The polarity (cable colors) must be correct or big trouble.
P.S. adding a 100mA in-line fuse on the power side (RED wire) is highly recommended.

Clear Skies!

ccs_hello


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James Cunningham
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Re: LNtech 300 shrink down new [Re: ccs_hello]
      #5428830 - 09/19/12 08:07 AM

It looks like all this cable does is extend the video connection and the power connection. Nothing for remote control.

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