Thread: Ambitious Video Security System

First off, I need to make sure I keep myself flexible enough to stop when I come to a realization. In most cases the mods can't be undone so easily, so planning ahead is important.

I need to come up with a wiring/connector arrangement that will be solid, since I do not want connections coming loose while driving. I have considered using ATX extension cables (computer power supplies) and ISO male and female radio harnesses. These should provide a pretty robust connection. How they will perform for the video connections will remain to be seen.

Anyone following this and planning to do this themselves, here is one of those "duh" tips that will get ya: Make sure each piece works properly and fully BEFORE you start opening and modifying anything. This is for two reasons: You won't be able to return it, and if it doesn't work after your mods, you will at least know that it must be your mod. I know, this sounds obvious and stupid, but it is SO easy to screw this up in your excitement.

I keep bouncing back to wanting a PTZ camera in the system. So, I bid on a Canon VC-C4 PTZ video conferencing camera. It is the smallest vid-conf camera I have found, has 16x OPTICAL zoom, and a fairly good range of motion. It is controlled by RS232C VISCA for which there is an enormous amount of information out there. It is powered by 12V (tolerant to abut 16V) and draws about 2A max. It is silver in color (I will have to dye the plastic to black like my interior.) It also comes in ceiling mountable VC-C4R which flips the image. The one I am bidding on is not the ceiling mount version, but if I decide to do it that way, the quad I have has the ability to flip the image!! This may be overkill, but damn, it would be nice!

That would mean 4 cameras again: Dash, front, rear, and PTZ.

Wish me luck!

good luck.

woh, now you got me excited... the quad does mirror flip! will it do this on an individual basis,each input???... I only seen one unit that ever did that, it was a grand vision I think... more info please!

Yer gonna wanna kick me! I was going from memory. I just powered it back up and went into the camera set up. No flipping, just mirroring. But, yes, settings are per input. As well as individual video adjustments (color, saturation, brightness, hue, contrast, and sharpness), and camera title. It is quite an advanced quad for its size. And it was only $64 shipped. The asia-products link I posted may also carry it for less, since I bought it from an ebay seller.

Hmm, as for flipping the camera, I would be surprised if there wasn't a small jumper on the camera board that does it. Most camera blocks I have worked with professionally have a bank of jumpers to set things like flip, mirror, NTSC/PAL, etc.. and these were the same found in Sony vid-conf cameras (EV-D30.)

I am in the process right now of pinning everything out to re-enable all the features lost. I found that the battery back up for the clock should keep the time for almost 10 years!! Don't think I will need to worry about that.

EDIT: If I could find the datasheet for the techwell quad processor chip this thing is using, I bet it would have the "flip" feature. Seems I did read that somewhere I was looking, which is why I thought the quad did it. I will email techwell and see if I can coerce them out of a datasheet.

I am not sure yet, but it looks like it is using a multiplexing scheme to share the ports on the micro. 8 Switches, 8 LEDs, and IR data on the front panel. I am still looking for what ports might be used for the triggers and relay outputs the higher-end model has.

OK. I emailed techwell for a datasheet, I gave them my work email address to look more legit The brochure for the TW2834 (this chip is TW2824) states horizontal and vertical mirroring. This is probably where I got mistaken. The TW2834 looks like a replacement for the TW2824, so I expect them to have most of the same features. The brochure for the TW2824 doesn't state vertical mirroring, but it also doesn't mention horizontal mirroring and it obviously does that.

EDIT: Found a different brochure for the TW2824 which does list horizontal mirroring. No mention of vertical mirroring...hmm
http://www.techwellinc.com/support/techdocs_download.php?did=79 can someone try that link and see if they can download the TW2824 documents (besides the brochure?) It acts like it is going to, but then just shuts down for me.

The micro in this quad uses flash memory and is pretty well documented and supported. It may be possible to modify the firmware to add this feature (I would like to do it anyway so I can start up in the PIP mode.)

Maybe I will be able to hook up SPI tomorrow and read out the firmware and see what I am dealing with.

Scott McDonnell

After a lot of testing, I was able to identify all but 8 pins on the micro. I will probably be able to identify if these are the alarm triggers and relay outputs only after running it and simulating alarm conditions. If I find a trigger, it should switch to the appropriate camera. The relay outputs should respond to the motion detection that you can set up for each camera. Here's what I have got so far:

The 20 pin header for the front panel:
The pinout is as follows (in logical order, not sequential)

The buttons serve 2 functions. One when pressed, and another when held for about 2 seconds.
Press/ Hold for ~2 seconds
1 AB/ Menu (always brings you back to 4 split screen on press)
3 Freeze/ Auto (Holding this button starts the sequencer)
5 Mode/ Zoom (Pressing switches between modes, including pip - 2 presses)
7 Enter/ VCR (holding switches in the DVR output)
9 Cam1
11 Cam2
13 Cam3
15 Cam4

Shorting any of these pins to ground is equivalent to pressing a button. So, all that is needed it to share a common ground with my micro and bring an output low. To be totally safe, you could (and probably should) isolate these with something (relay, optoisolator, etc..)

2 Corresponding LEDS (all)
4 "
6 "
8 "
10 "
12 "
14 "
16 "

17 GND
19 IR Sensor data
18 Power LED
20 VCC for IR Sensor

There is a second 2 pin header that I did not highlight in any pictures that the power switch connects to.

Probably wondering why I am bothering so much with reverse engineering this stuff. It is because I want to integrate the features built in to these components as much as I can. For example, the zone triggers could be connected directly to the cam buttons on the quad to switch in the camera covering that zone automatically.

This reduces my programming and frees up IO and resources of my micro controller allowing me to use to incorporate more features (like GPS, Cellular SMS, etc...) later on if I want to.

mirror is enough, I don't need flip really, they don't even list mirror in the specs on ebay... I'm going to get the same one you got so I know it's mirror capable...

I've thought about doing this for a long time, but your just making it so easy by doing all the r&d... I think I'm going to order this stuff & follow along awsome job so far...

are you planning a microcontroller to control this?

edit, of course you are, but are you programming it yourself?