Here's a link to my recent project - a capacitance measurer made using the Arduino. It worked very well surprisingly.
I thought I'd put it up here to get feedback and whatnot, and possibly find a better way of doing it.
Hope you like it!
Thanks for looking,
That's way cool! I was hoping someone would tackle one of these.
Don't worry about a timer. There are articles for at least 2 in the "playground" area and others here will probably have suggestions. What kind of resolution do you need?
Do you have any thoughts on measuring tiny capacitance - i.e. 22pF and the like?
Yeah, I only really wanted the timer so that I could do real calculations (t=RC , etc...), not all that proportionality stuff!
As for the 22pF capacitor, with the 12Mohm resistor (it's 4/5 series resistors) i've used, the time the arduino has to record is 0.000264 seconds or 264us. It should be able to cope just fine. If not, just increase the resistance. It just means it takes longer to charge up the capacitor, hence, more time for the arduio to record.
Hope that helps.
You probably want to use high precision resistors for this as well, seeing as how the standard resistor has an uncertainty of perhaps ±5%.
Yeah, that or measure them. Though I suppose it would be corrected by the graph.
When I get a bit more time, i'll try and imporve it A LOT.
Thanks for your input,