&gt; <i>Making a small screen consisting of only a single LED and moving it close to the camera doesn&#x27;t change that...so long as the two are hardwired and one or both are programmable, there&#x27;s no certainty.</i><p>This doesn&#x27;t make any sense. Do you not know what &quot;hardwired&quot; means?<p>Rig the light so that it is turned on any time the camera is transmitting to the CPU. This is a physical interface, not a software one. You can hack the camera software any way you like, but anything that receives an image from the camera will activate the light.<p>&gt; <i>Short of removing the camera from the device, physical disconnection is the next best thing. To put it another way, a camera can shoot at 1&#x2F;2000 of a second. That&#x27;s quick enough that a person will miss the blink of an LED even if it&#x27;s activated 10 times as long as the shutter is open.</i><p>So activate it longer than that. Why is this a problem? You can easily wire the light to activate for a minimum of one second (or more, if you like) any time the camera transmits even a single frame.