0verence 8 years ago Sorry about my poor English, but what does "whc i opend" mean? So you have a comp mouse (I assume that means a 'computer mouse' - as I said, English is not my first language). Plug it into the computer and it will take the supply power from the computer (5V DC btw.) If you don't have a computer, what do you need the mouse for? So, let me make a wild guess and rephrase your question: 'I have this computer mouse with this cool light effect. Now I want to have this light effect without the mouse being connected to a PC. Is that possible?' If, just in case, that is close to your question, then yes - and no. Yes. If you supply the mouse with 5V DC the LED should light up. If you just have a 9V battery, you will need some kind of 5V regulator (7805). No. Most modern mice just turn their bright light on, when they detect that they are moved. So, without moving the mouse, you'll just get a short flash.