Samstag, 23. April 2011

Poor Man's LANC for Kodak ZX1?

After more than two years (and countless photos using my Ixus 55 Stereo-Rig) I stumbled over a real bargain for Kodak ZX1 camcorders: A german online-shop sold them for 49,- EUR. I decided to order two of them to check if they can be used for HD stereo videos. Apparently this is by no means a new idea: Several people have successfully used these camcorders for 3D-Stereo especially because this model offers a 1280x720 resolution at 60p, so that the maximal sync-error between frames is not larger than 8ms.

For 3d Stereo-Vids having perfect sync is very important to avoid eye-strain in scenes with a lot of movement. For the more expensive Soncy-camcorders a very good stereo solution based on the LANC-protocol exists. Here a suitable remote control can switch on both camcorders at exactly the same time so that their internal oszillators start in perfect sync. Using LANC it is even possible to measure the deviation between the oszillators so that you can see when the cameras begin to drift apart slowly.

For the low-cost Kodak ZX1 there is no such thing as a LANC-port, but the Kodak has a micro-USB port that might serve a similar purpose. When I plugged the USB-cable into the camera, I noticed that it automatically turned on. Apparently the camera is sensitive to the 5v USB voltage that is provided by the USB-host. I still had various electronics parts lying around from my experiments with Canon CHDK/SDM and decided to construct a remote control that would switch on both cameras in sync.

First of all I had to work on the USB-cables. Unfortunately the Kodak uses a non-standard 8-pin micro usb-plug so I had to use the original cables provided with the camera. Using a sharp knife, I removed all the plastic and ended up with the following small plug:

I then used the most simple electric circuit possible to power the micro usb with a 3,6V lithium battery and a push-button:

Pressing the button provides 3.6V to the corresponding USB-contacts. So I ended up with the following Stereo-Rig:

I still need to work on the second plug, but this should be sufficient for testing purposes. So how does this work:
A short press on the yellow push-button powers on both cameras in sync. Bingo. Even better, when I press it a little longer, the camera switches off again. I have no idea why the camera does that but apparently I created a real on/off switch by accident, nice. ;-)

To start and stop recording you still have to use the buttons on the camcorder, but since you have to edit the video clips afterwards anyway this is only a minor inconvenience. As a workaround I could buy a IR-remote for this purpose but the IR-receiver is located on top of the camera so it is not really more convenient to start recordings this way.

The next step will be to test the sync of the resulting videos and in particular to compare the sync with the standard method of switching on both cameras separately. Stay tuned ... ;-)

1 Kommentar:

Murli hat gesagt…

Check this guys 3d Camera made using a Beagle board!