Oil pressure switch?

My engine has a oil sensor or oil light problem, how do I troubleshoot the problem to fix?

I had a low amount of oil in the car, than the oil light started blinking I stopped the car filled it up with oil and the light stopped blinking but when the engine was running for 20 miles and the light began to blink again do you know what might be wrong?

I have a 1992 Honda Accord EX 2.2L with 305650 miles on it and as of Friday the low oil pressure light flashes on and off. It only comes on after driving the car for a while. Sometimes it flashes dim like there might be something wrong with the wire. Well I went to the auto parts store and bought a new filter and oil pressure sensor and I can't find where the sensor is. I think it is right above where the oil filter is, but I am not sure. I was told that the only 3 things that would make that light turn on were the filter caving in on itself, the sensor or the oil pump. This car was owned by a honda dealership employee up until about 6 months ago when I bought it from them. This person always got all the routine maintenance done. Any input on where the oil pressure sensor is and what you think might be causing the problem would be greatly appreciated. Thank You

Thanks! I got it changed out.