40 replies to this topic

[ccs_hello]

This is the revised instruction (July 5th.)

Note although my July 4th design (now removed in this thread) worked in an experimental setup, I need to make some changes and add protection circuits to make it stable.

*****
This is a re-edit of my PC-control design for "remote controlling the push buttons".

One expert had noticed me my earlier design (July 4th design) assumption made an error. I reviewed my design and decided to redo the circuitry.

The design is no longer RS485 based but a simple LvTTL (some simplified it and called it TTL) RS232 based design.
I have built the design and tested it out using a 132 ft long cable and it works fine. The new circuit also has the protection circuits on both the camera end and the USB-Serial dongle end.

=== Main Text starts here ===

If you don't want to use a physical handbox with 5 buttons to remote control that little LN300 videocam (see my previous project here in CN.)

Using a PC-based control under "TTL-level RS232"** signaling, with a remote PC and a long twisted-pair cord, you can accomplish the same task.

** Note: do not use a real RS232 port or full-blown RS232 dongle. Use a simpler and cheaper (e.g., $1.02 shipped) TTL-level dongle as specified in my later post.

This is a very low cost project on a Lntech LN-300 videocam (don't call it security cam, it is really a capable multi-purpose videocam!)

It is also very easy, so long as you have a good soldering skill, thin (pencil like) soldering iron, and fine diameter solder.
Since the soldering is on two fine-pitched solder pads (1.0 mm pitch), you have to be extra careful.

You need to have two short pieces of wires (I used 30-gauge wire-wrap wires) and one 3.3K ohm 1/8 W or 1/16 W resistor.

You need them on the camera side.

On PC side, you need to go to that famous auction site to buy a USB-RS232_TTL-level dongle. The price varies from as low as $1.02 shipped (plus the long wait.)
Then you also need to add one more 3.3K ohm 1/8 W or 1/16 W resistor on this end.

The cable used in between is a pair of twisted cable.

I'll show the completed project first.
The picture shown is the resulted DIY.

P.S. note my LN300's rear pilot light is RED colored.

Clear Skies!

ccs_hello

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[ccs_hello]

This is the front of LN300's CCD board. Note the holes: T and G. We will solder both holes. Also note the pitch (center to center) is just 1mm so you'll have to have a good soldering skill.

Clear Skies!

ccs_hello

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[ccs_hello]

The other side: note the RJ-11 DSP.

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[ccs_hello]

Solder a 3.3K ohm resistor to hole "T". Note: soldering from the front side (CCD side.) In this picture, you can see the resistor "standing" vertically.

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[ccs_hello]

Solder one "black" wire (I used the thin 30-gauge wires) from the front side on the "G" hole.

Solder the other wire ("Blue" wire) from the back side onto the other end (open end) of the resistor.

Note I used 2 different colors to distinguish T and G.


These two wires are the LvTTL-level RS232 wires and it is ready to be connected to the outside world as the interface.

You now need to make a decisions:
What type of connector you want to use to link the camera with your USB dongle?

1. You can re-purpose LN300's DC-IRIS 4-pin connector, since it's not used in astro-applications anyways (this is the approach commercial AVS and MC use on RS485, here we use RS232-TTL.) Con is you have to find or buy a mating male-side DC-Iris connector somewhere.

2. You can drill a hole to mount a 3.5mm stereo socket as the connector.

or

3. I opt for a non-permanent solution for now, by just direct-wiring the cable to the USB dongle (see first post.)

Clear Skies!

ccs_hello

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[ccs_hello]

Now use the regular push button on the back of videocam to configure the camera SETting.

For illustration purpose, let's use MC Micro's designation:

"COMM. ID" set to 1

"BAUDRATE" set to 9600.

See attached picture.

By the way,
AVS DSO-1 setting is different:
"COMM. ID" set to ???

"BAUDRATE" set to 38400.

Select either one, in PC software side, you just need to pick the matching model.

Camera side of the setting is complete.

Footnote: notice the right-hand side "issue" on my LN300...
I think one vendor solved it.

Clear Skies!

ccs_hello

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[ccs_hello]

Re: USB-RS232 "TTL level" dongle

Popular dongles are either FTDI (FT232) based or Prolific (PL2303) based.

You can find it in that famous auction site, e.g., item 121233021072 (total cost: $1.02 shipped!) If you know where to get the "proper" driver, Win8 is supported. FTDI based typically costs $10 or less, also shipped. This FTDI dongle costs $4 shipped.

.....


Now that the USB dongle you purchased just arrived .


The one I have purchased has 5 connectors, you can clip them off (see 4th pic.) We will direct solder one wire and one resistor on the PCB.

Clear Skies!

ccs_hello

[ccs_hello]

On the back side of that dongle's PCB near 5 connector PINs, identify two holes: GND and TXD.
Solder the other 3.3K resistor on the TXD hole.
Solder the "Black" wire to the GND hole.
Solder the "Blue" wire to the other end (open end) of the 3.3K resistor.

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[ccs_hello]

Basically, it is Black wire connects to Black wire and
Blue wire connects to Blue wire. (See the first picture.)

If you need a longer cable, the easiest source will be from a long Ethernet cable. Such cable has 4 twisted pairs. Just use one pair for this application.

====

Plug the USB dongle to your PC, it will be detected and driver installed. From "Control Panel" > "Device manager", it will be shown as a COM Port (Under "Ports".) Note that port number, we'll need that information later.

Clear Skies!

ccs_hello

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[ccs_hello]

There are couple of videocam control software that can be used to control the now modified LN300.
AtroLive is one of them and the other one can be found in Mallincam's download site.
There may be others.
(Edit to add:
CamControl by Steve Uckerman,
AstroVideoControlPanel, etc.)

You just need to select the correct videocam model, set the COM port number, and you are good to go!

This concludes the project.

Clear Skies!

ccs_hello

[A. Viegas]

CCS- Very informative tutorial and description - thank you...

I think if you are an expert engineer or DIY'er like CCS then this project is a great way to save $30 over the cost of a new Mallincam Micro or the AVS DSO camera. I started to think maybe I could buy one of these LN300 on ebay and do the modification for fun. So not being much of a DIY'er, I have to buy the soldering iron, kit, wires, USB dongle, wires. On Amazon and on Ebay I calculate it will cost me about $45 for the cheapo soldering iron and other assorted items. Of course now, this project no longer seems so exciting, it WILL COST ME $20 to do it myself, or I can just pay $99 for what Mallincam or AVS already does...

Al

[David B in NM]

Al,

I agree with you for the "first time" startup cost for persons such as yourself. However, there are also people out there like me who have most everything to do this project on-hand already. The only thing I lack is dongle.

I've already used his (CCS's) plan for the wired remote box (fly wired). It works quite well.

DIY electronics projects like this are actually a nice way to relax.

I believe you'll agree, the initial startup cost of anything applies to all hobbies. A $45 investment is far cheaper than the initial cost one has to fund when you get in to astronomy. Right? Many items are just a one-time expense and can be used for future projects.

To me, both are relaxing hobbies. Maybe someday you'll give it a shot.

David B in NM

[ccs_hello]

Al,

I agree with your assessment (commercially supported and very inexpensive solution.)
Kudos to these vendors!

Over years, I have accumulated too many gadgets and toys, including the LN300 when it was first discussed in CN .
Sometimes I find having tools readily available help a lot for a completely different reason: e.g., fix a broken wire in a radio, etc. just when you need it to work urgently.
Another reason: use tools as garage decorations.

Clear Skies!

ccs_hello

[ccs_hello]

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[ccs_hello]

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[barbarosa]

I (and I hope others) appreciate that you are looking at this cam (and it its close relatives) without marketing hype. Your DIY instructions may not save much money, but they help us to understand what is in the camera and how it works.

[ccs_hello]

This July 5th update is based on RS232 LvTTL signal level.
It has been tested on a 142 ft cable.

I do apologize on the full RS485 based solution.
For that I have to get an extra "RS485 receiver" circuit ($2 or less) added. For short distance, I think the current solution is good enough and won't break a bank.

Clear Skies!

ccs_hello

[RandyC]

Clear Skies!
ccs_hello

LOL

[A. Viegas]

Al,

I agree with you for the "first time" startup cost for persons such as yourself. However, there are also people out there like me who have most everything to do this project on-hand already. The only thing I lack is dongle.

I've already used his (CCS's) plan for the wired remote box (fly wired). It works quite well.

DIY electronics projects like this are actually a nice way to relax.

I believe you'll agree, the initial startup cost of anything applies to all hobbies. A $45 investment is far cheaper than the initial cost one has to fund when you get in to astronomy. Right? Many items are just a one-time expense and can be used for future projects.

To me, both are relaxing hobbies. Maybe someday you'll give it a shot.

David B in NM

I hope one day to give projects like this a try... but the last time i used a soldering iron was in middle school shop class!

Kudos to you for not only having the equipment, but also the skill to do it... i suspect you are right that it can be fun to do it yourself and even if it costs a little more you have the satisfaction of having done it yourself!

Al

[Live_Steam_Mad]

For those who would like to do this lv-TTL PC control modification (as shown, solder 2 wires onto PCB, and 2 wires onto the 1 USD dongle), and want to come out of the camera via the connector on the back of the camera, I found this Auto Iris 4 pin connector plug with male pins at Maplin ;-

 

http://www.maplin.co...ctor-plug-l18ah

 

...for 2 GBP (beats paying a lot more on Ebay once postage is added from the only seller I saw in USA). I have a local Maplin store 2 miles away so I'll try and get in there and get one soon. My camera has been ordered and was dispatched 2 days ago so it'll take a while. I already ordered the dongle. I'll do the mod. ASAP.

 

Best Regards,

 

Alistair G.

Edited by Live_Steam_Mad, 19 September 2015 - 07:01 PM.

[Live_Steam_Mad]

I ordered the exact Ebay item number that you gave and my USB to TTL dongle arrived and it has a different order pinout on the end ;-

 

 

 

Do I still solder the resistor to the TX on the dongle, and the other wire to the GND on the dongle?

 

BTW I just tried it in my Windows XP SP3 PC and it auto installed, showing "Prolific USB-to-Serial Comm Port (COM5)" under Ports (COM & LPT) in Device Manager. I get a red light when it's plugged in, and a flashing blue light every time some data is sent after "connecting" (i.e. when I press any of the OSD buttons in the software on the PC screen).

 

Regards,

 

Alistair G.

Edited by Live_Steam_Mad, 02 October 2015 - 07:45 PM.

[ccs_hello]

Alistair G.

 

yes, Tx and Gnd pins.

 

Clear Skies!

 

ccs_hello

[tjay]

Be warned, I've got the same USB to TTL level serial dongle, and with Win 10, I had to use the following instructions to get it recognized properly:

http://www.airdevila...nstallation.pdf

[ccs_hello]

Oh yeah.  Only use vendor provided driver CD or download site given by the seller.

The climate has changed.

Edited by ccs_hello, 02 October 2015 - 09:56 PM.

[tjay]

Does the watt rating of the resistor matter? I can get a 0.5 watt 3.3k ohm resistor nearby, but I may need to hunt a bit more for a 1/8 or 1/16 watt one