From: Mike Monett
*snip* HeHe - the AD7791 takes 16.67 samples per second. If you allow 4 bytes for the 24-bit data, and do a 10 hr run, that's 16.67*3600*10*4 = 2,400,480 bytes of data. Add a 4-byte time stamp, and you have a lot of data. A bit too much for a simple MCU to store and crunch, I'm afraid. Most of the stuff I do these days ends up with 10 or 20 megabytes of data. Fortunately, I found a way to access all the Extended memory in one contiguous block from Pascal so I don't have to go through HiMem, which is painfully slow. Displaying the data is another problem. Most Windows programs choke on million-vector data files. So I now have my own routines in Pascal and assembly that just zip through the data and can do pretty much anything I want. ************* Of course an MCU can't do all of that but it could use a serial port for downloading, programming and dataloging to a PC. You can write a GUI or do it with DOS. For stand alone opperation the display could be a simple seven segment LCD and a cheap numeric keypad. Use voltage pumps for the electrodes and run the whole thing from one small battery. > I guess that's overkill when a battery and a resistor (or a "grain > of wheat" lamp) will do the job just fine. Sure - it's great when you finally figure everything out and just want to make cs. I'm still trying to figure out what kind of electrode configuration, operating current, and quality of dw gives the highest ppm. Godzilla is the best so far, but it's not the final answer. ************* Good luck on your quest for the holy grail. > Best wishes, > Andy (^_^) Best Regards, Mike Monett Best wishes again, Andy (^_^)
