hello,
I want to create extension cable that detects and logs when device connected to it is turned on.
Although I have no problem in creating circuit that logs events I do not know how (in easy way) detect if device (that is connected all the time to extension cable) was turned on or off (co I can log this event)?
Can anyone help me with it ?
Do you want detection when the device is switched on at the device (current flow), or, turned on at the wall (voltage)?
Weedpharma
If you want to measure the current, drawn by the device, there exist various solutions. One would be a small resistor (depending on the current drawn), a diode and an optocoupler. Or simply a small lamp and a phototransistor?