First off you PIR sensor should not be shorting 5v to the gpio input pin , the PIR sensor should be outputting 3.3v. Connecting 5v to the gpio will damage you pi.
So having got that out of the way, the simple way to set up a remote trigger is to set another gpio pin to output and connect it the the input used for the PIR using a 1K resistor.
Now any time you want to remotely trigger you PIR/camera all you need do is drive this gpio output high for 1 second or how ever long you want.
Please only ask questions in the forum I will not answer questions sent to me directly via PM
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