I'm working on a very time limited project (8 weeks). Basically I need to perform measurements and save to memory. 2 identical boxes, 4 hours and no wireless or wired connection. Each box is measuring on accelerometers.
Due to the limitation in time I need a platform with minimal soldering, PSU design and so forth.
The Arduino is an obvious choice but the crystal is simply to unstable. I need precision of +/- 30 ppb of clock frequency.
I've found OCXO that meet spec but not at 16Mhz..(or 8).. Changing the clock speed to 12 MHz would help me a lot - but then the libraries becomes an issue.
My idea so far is to use arduino, write a program that sets a digital pin high, then waits x microseconds and then sets digital pin low. This way I can calibrate the x using a oscilloscope to land the right frequency of sampling.. hmm