Spying on another circuit's speaker or LED

I have a basic laser gun set. These laser guns make different sounds and blink LEDs when you hit each other. I would like to inject a small arduino to keep track of some stats - how many times hit, etc. I have some basic electronics knowledge and have built some arduino projects in past.

Question: Is there a way to "monitor" the speaker or LED hard lines using arduino so when a certain action happens on these lines, I can do something in my arduino? Besides arduino, I would like to use the least additional hardware as possible. If possible, to make it robust, I would like to hook into the hardwires and not use a mic that can listen to sounds or another hardware that can detect the light of the LED as on. Also, hooking into the existing IC of the laser gun would be beyond my skillset (I opened it up and the IC has no written markings on it).

Please help me to get this fun project started.

matrixIII: I have a basic laser gun set. These laser guns make different sounds and blink LEDs when you hit each other. I would like to inject a small arduino to keep track of some stats - how many times hit, etc. I have some basic electronics knowledge and have built some arduino projects in past.

Question: Is there a way to "monitor" the speaker or LED hard lines using arduino so when a certain action happens on these lines, I can do something in my arduino? Besides arduino, I would like to use the least additional hardware as possible. If possible, to make it robust, I would like to hook into the hardwires and not use a mic that can listen to sounds or another hardware that can detect the light of the LED as on. Also, hooking into the existing IC of the laser gun would be beyond my skillset (I opened it up and the IC has no written markings on it).

Please help me to get this fun project started.

The LED will obviously light up when it gets power applied to it.... eg. from a voltage source. So if you are able to tap into the source that feeds power to the LED, and if it can be done conveniently, then that could open the door for the arduino to get involved.

Southpark:
The LED will obviously light up when it gets power applied to it… eg. from a voltage source. So if you are able to tap into the source that feeds power to the LED, and if it can be done conveniently, then that could open the door for the arduino to get involved.

Yeah, so there is positive and negative going to LED. splice the positive and put a connection in parallel going to one of the digital input pings of Arduino as a input?

matrixIII: Yeah, so there is positive and negative going to LED. splice the positive and put a connection in parallel going to one of the digital input pings of Arduino as a input?

Yeah... maybe. The idea is to be able to measure and detect a change.... like a change in voltage or current whenever there is activity.... so need to monitor a state of the led.... or monitor a state of the device that drives the led.