After having to wait for restock notification before ordering I was finally able to get a couple of items from ADAfruit that looked especially interesting to me. They arrived yesterday and both products get a lefty's thumbs up report.
First is an assembled (minus soldering on stacking headers) SD/RTC shield board for just $20. This thing is sweet, worked right off the bat and has good library support for both the SD and RTC. Everything functioned using the example sketches, although you do have to edit some SD sketches to utilize pin 10 for SS function as several are set up for a ethernet board that uses pin 4 for the SS. They include the back up battery for the RTC. The board has a two uncommited led/resistor networks for one's use and the board has it's own 3.3 vdc regulator to power the SD, it duplicates the pin13 led on board. It has a system reset switch, but does not have dedicated ICSP 2x3 pin headers. They use a real voltage translation chip rather then voltage dividers for the SD logic to arduino voltage conversion. Anyway great price, great quality, good library support, what more could one want for the basics for logging applications?
Second item is a $10 4 channel (or 2 channel differnial) 12 bit I2C ADC chip/module based on the TI ADS1015 chip. This cool chip has built in internal voltage reference, 6 different gain settings, voltage comparator with output pin, and many other features and functions. It's a great little chip that does a lot. Adafruit has a library that supports the chip and I had no trouble getting it to function. Maybe not really needed with the arduino having built in 10 bit ADC pins, but I just felt that the SD/RTC data logging shield was just begging for the extra precision and features this little ADC module would bring to the party. They also carry the same module equipped with the 16 bit ADC version of the chip called the TI ADS1115, for $15. So I just soldered a 10 pin male header onto the SD/RTC board and soldered a 10 pin stacking header on the ADC module so the module can live on the SD/RTC shield or be easily unplugged and used elsewhere if needed.
Well that's the report of the latest. Adafruit is great at Arduino support and makes and documents well a lot of very cool and useful stuff, check them out if you haven't already.
Lefty