I have a couple of Philips PM2525 bench DMMs both of which work but one had it's battery run out and so is now showing as "CAL" but it still reads accurately and both have LCD displays which are beginning to fail. Now Philips use I2C inside their bench DMMs so that the processor can "speak" to the display driver. I have seen examples of people reading the display information and using a micro controller to decode this information and display it on a new LCD.
I have the circuit diagram and can locate the I2C stream but if I try and hook an arduino to it then the controller and display driver get confused with this interloper being on the bus when it shouldn't.
So.....
Any ideas how I can read the data off the bus without the display driver IC or micro controller getting upset? I've had a few ideas such as using an op-amp an a unity gain amplifier and passing this to the arduino but the libraries I've been looking at want to communicate rather than just read.
I got the idea from a similar project where the person doing it uses a different PIC - ADI公司 | 混合信号和数字信号处理IC | 亚德诺半导体
I think the biggest issue may be arduino's libraries wanting to link with the device rather than just decode it.