How do you turn a VCR

The sloppy way is to simulate punching the record/play and stop buttons on the VCR remote control. See:

Scroll down to "Surveillance camera recorder".

The right way(tm) is to use a VCR or DVR that's designed specifically for the purpose, which always has a way to initiate and stop recording. The also may have motion sensing features, which will probably be your next question. Search Google for "security camera DVR". There are also DVR kits for building a multi-camera system, where you supply your own hard disk.

Use 2 relays. One for play, one for stop and connect these parallel to the button switches. My 'anonymous caller killer' works the same way using a CD player.

could you do it with a PC and web cam ?

this would probably be easier, you can get all sorts of motion detection software etc, in fact I would be surprised if you couldnt get something that already does exactly what your trying todo.

plus if someone stole the VCR it would take away the evidence, with a PC you could at least stream it to a website ...

Colin =^.^=

Brendan Gillatt hath wroth:

Once you have a PC, all manner of things are possible. No need to use a webcam as there are 4 port PCI video cards available for about $16 on eBay.

I've used these and they work quite well.

There's a reason why commercial security DVR's use NTSC video and not USB. The problem with USB webcams is the 16ft maximum length of the USB cable. NTSC video will go much further (depending on cable quality). I have one run that's 75 meters long. You can purchase USB amplified extension cables, but my experience with two of these were unimpressive. I also had to supply my own +5VDC power at the camera end. It's also rather difficult to buy a wireless camera with a USB interface, while NTSC video wireless cameras are common.

There's also the problem of truly crappy video from commodity USB cameras. If you wanna actually identify someone on video, you would need a much better camera and optics than commonly found on USB web cameras. Common security camera features, such as auto-focus and auto-iris and usually lacking (or marginal) in USB web cameras. There are some exceptional good quality USB cameras available, but these are mostly the same security (or inspection) cameras with a USB, firewire, or Sony Camera Link interface, instead of NTSC video.

The other problem with a computah is power drain. Most hard disk based DVR's are very simple devices that don't such much power. Most PC's are not. With PC based video, you can't just shut down the PC to save power, as there's no hardware method of waking it up again when something interesting appears. You could use an PIR motion detector, but now things are getting rather complexicated.

It's also possible to build a security camera recorder around a video server. I've been using Aviosys IP Video 9100a boxes with marginal success. About $80 for 4 ports.

Cheap, but with really awful firmware inside the box such as Active-X control for streaming video. However, the idea is good if all you want to do is monitor a mess of remote cameras (without a PC at the camera end). I have one running with just the cameras, video server, motion detection, and NAS (network attached storage) box to collect images (via ftp).