Gah. Now that I've said it, I have to actually attempt this sort of automation.
It's probably going to be ugly, but I think I can do it with all hardware without any programming. If I was a programmer, it should be relatively straghtforward to send infrared commands with an IR LED to the playback VCR or Hi8/D8 camcorder to tell it to stop playing after a certain settable period of time and then also send a signal to the recorder to stop recording. Computer based capture programs probably wouldn't be too hard to have a countdown timer before a capture is stopped triggered to stop a capture.
Turns out they do make inexpensive LANC controllers which you could use for anything with a LANC port - this includes most Sony Hi8/D8 cameras and the AJA KiPro. Since things are likely going to be left unattended, ideally you'd just have the tape stop either by cutting power to the VCR with a relay on the power plug or sending it a "stop or "eject" command when done.
For the longevity of the player, I'd rather stop the playback than have it finish the playback and rewind. These tapes honestly probably don't need to be rewound and that's going to put more stress on the mechanisms that they don't need if they are going to get through hundreds of tapes each!
So basically I'm thinking you could just tap into an original remote or a programmable remote to emulate switch presses either directly or via a transistor of some sort.
Most basic would be to use a delay timer relay like this:
https://amzn.to/3Aji3wn
...and then wire the the delay timer's relay output to the "Stop" button of this small LANC controller to stop the AJA from recording:
https://amzn.to/40ndv2O
That'll make it easy to set the number of minutes to capture for each tape that is visually easy to set/change with each tape.
As for how to stop the VCR and other equipment (in the interest of longevity and avoiding rewinding):
1. It's probably not technically bad for a VCR/Camcorder and TBC's to just be unplugged from power to turn them off (most TBCs just disconnect power at the mains anyway) and this is essentially what happens whenever a camcorder battery dies, so you could have the TBC and playback device on a power strip that is kept on by a relay, that could be wired to disconnect along with the stopping of the recording device.
2.You could make the VCR power off with a cheap learning remote to learn the original eject or stop button code for whatever VCR we are using something like this and then hard wire it to the same relay that's stopping the other device:
https://amzn.to/3UsZH2H
3.A servo could be used to physically press the power button if you don't want to mess with infrared, but that's got more possible ways to fail.
4.Directly run jumpers to the "stop" button on the VCRs PCB and have the timer relay interface with that via a detachable 2-wire plug that exits the VCR.
Since the recording device may not stop instantly and may not like it if the playback stops first, you could also add a delay relay that will wait something like 5 seconds after the recording device stops using something like this:
https://amzn.to/4eZ53ed
Also, for computer capture programs, they typically do have keyboard shortcuts for stopping a capture - I think it's actually just the escape key in
Virtualdub. For that, you could just get a cheap USB keyboard and figure out where the escape key is on the matrix of the keyboard controller and wire just the controller to the delay relay and it'll tell
virtualdub to stop capturing when the delay relay turns on. I once shoved and entire keyboard controller inside of an NES controller and wired each controller button to the membrane matrix and it all fit and worked fine. One or two buttons for a keyboard shortcut should be muuuuch easier than 8 haha. These days, you could just use a small Arduino to emulate a keyboard combo without doing much in the way of coding as keyboard projects are readily available. I think mouse clicks can also be emulated as well.
WinDV I'm not sure if actually has a shortcut. For those without shortcuts, you could just have the mouse hovering over the stop capture button and wire a cheap USB mouse for that click button to be activated by the relay instead.
