Trigger with separate current

So here's my setup, basically I have an arduino with its own power source. The battery is rechargeable and I have a wireless charger receiver hooked up to it (Like the one on some phones.). My question is, is there a way I could trigger an event whenever the charging pad is placed on a charger dock and current starts to flow through the pad.

The current code I have is set up so that pressing a button will trigger the event using INPUT_PULLUP. Would I be able to just solder some leads from the receiver pad onto some of the arduino pins with some resistors or something and change the code to something else?

Quite possibly. You would have to condition the signal from the coil so that it can be sampled by the Arduino without destroying its input pins. There are various ways to do that, and it will matter how the coil is connected to the charging circuit too. Do you have specs on the charging pad? Have you opened it and photographed it?

The charger module is a Micro USB 5V 1A 18650 TP4056 (https://www.amazon.com/gp/product/B06XQRQR3Q/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1)

The pad YX&SH Qi Receiver Mobile Phone Wirless Charging Reciever (https://www.amazon.com/gp/product/B07VK11961/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1)

The charger module actually has two front pins that can take power from the charging pad that is connected to it and doesnt draw from the battery if those two pins are used. The pad puts out 5V/800mah. I have the arduino hooked up to the back two pins on the charging module for out- and out+, not B- and B+ which are for the battery only. The arduino works just fine on those two pins, since the module re-corrects the voltage into 5V DC.