Hello, I am working on a project to measure the resistivity of salt water. As you probably know, just putting the leads of a multimeter into the water won't work because when the leads hit, they put a charge into the water. I was thinking that if I used a short DC pulse, something like 10ms, then I wouldn't affect the measurement as much. I'm trying to figure out the cheapest way to do this. The requirements are to:
1. generate a short DC pulse when a button is pressed
2. read, convert, and scale this to a resistance measurement
3. store the measurement for later viewing
4. reset the stored measurement to 0.
The measurement can be read by a multimeter, but I need it to be stored long enough to read it.
Can this be done for under $10 each assuming want to build 50 of these devices? I am not against buying a small microcontroller and programming it before it goes into the field.
1. generate a short DC pulse when a button is pressed
2. read, convert, and scale this to a resistance measurement
3. store the measurement for later viewing
4. reset the stored measurement to 0.
The measurement can be read by a multimeter, but I need it to be stored long enough to read it.
Can this be done for under $10 each assuming want to build 50 of these devices? I am not against buying a small microcontroller and programming it before it goes into the field.