Current sensor - simpler option?


I would like to detect the state of my computer monitor(standby or on) by measuring the current draw of the monitors power supply.

The supply is rated at 1.7A@19v when the screen is on, and 0.3W when in standby.

Initially I wanted to utilise a ACS712/ACS711 based idea. But then, given that I will be working with a 3.3v pro mini and the rather limited availability of the ACS711, I was started looking into other alternatives, such as TI's INA250.

But, am I missing a simpler option? As I only need to detect LOW or HIGH current. Is there a more efficient way? I also explored using the HDMI interface to try and determine the monitor state, but that seems a bit more complicated.

you could measure the amount of light it produces with an LDR? if it is low and constant => standby?

I considered that, but the ambient light keeps changing plus I don't want something in front of the screen.

Use a reed switch make a coil with 2A rated wire around switch, and voila - on/off sensor is ready.