I need to measure and display on a 2004 LCD the current on a spot welder up to almost 1,500 amps. The output voltage is only approximately 2.5VDC. I have not seen any kind of sensor that would even come close to working. I'm using a UNO R3, ATmega328P-PU to control the spot welder and would like to use it with a display for the current. I'm using #2AWG welding cable for my leads and thinking if I measure the voltage drop across about 18 inches of one lead I should be able to get about 200 millivolts. I will have to do some testing and measuring to get the exact length but it looks like 18 inches is going to be close. My plan is to have it at a point I get exactly 200mV, that way if all else fails, I've found a digital meter I can use and it uses 200mV for full scale reading. My thoughts are, if I filtered that 200mV with a LC filter I might be able to feed it directly to an Analog input. Since this is a spot welder and I will be reading directly off one of the leads, I'm sure there is going to be some major spikes during the weld pulse and will need to be filtered pretty good. One of my concerns is, since the Analog inputs are 0-5VDC, is 200mV enough signal or will I need to look for a way to amplify it. This will lead to another problem, I have pretty much been out of the electronics world for 25 years, since I retired (yea, I'm and old fart) and while I do still remember a lot of the basic stuff, I not the sharpest knife in the drawer on the newer stuff. After all. I was still working on a lot of vacuum tube equipment when I retired. The next major hurtle is I'm familiar with the Arduino UNO R3, I've been using it as a PID to control my coffee bean roaster for a couple of years, I'm not much good on programming.
So, Is there anyone able and willing to help, or is this one of those you wouldn't touch with a 10 foot pole?