Sunday, 27 May 2012

Questions Remain (Answers Elude)

Answers to these questions may get added later. More questions will definitely get added. Red ones are still unresolved.

What is it about the Data Logging Shield that makes it incompatible with the Arduino MEGA? It would be really useful to have it work on that board with the additional ports. Details are now on Adafruit.

Why is the file creation time stamp on the logger not correct? provides code to get the date right with the distributed SD library. Implemented in RWSloggerV2.

Why do so many of the examples use raw output rather than sprintf() to format? Is it a code size thing for stdio.h? BareMinimum compiles to 466 Bytes with a completely null program. Add an 80 char string and print a line to serial in setup gets it to 1996 bytes. Include stdio.h for no change. sprintf() the same test line jumps it to 2066 bytes. Put a more complicated sprintf() in the loop function and it jumps to 3674 bytes, so it doesn't seem like a big problem.

How do I create libraries of my own to use in sketches? It would make the sketches a lot less cluttered if I could put my own standard setup code in a library. It really is as simple as it looks: create a .h and .cpp file and put them in the libraries file tree.

What should be the DC voltage on the power supply to the Motor Shield? I attached a 20 volt supply from an old acer laptop and ran the hobby motors up to about 6 V PWM without letting any of the smoke out. I think the driver chips are good to 24V, but not 100% sure.

What are the voltage / current ratings on the little hobby motors that come with the starter kits?

How about the steppers labelled PF35T-48L4?

Can I get the serial port window to open automatically on program start after the upload? Maybe not, but the little magnifying glass on the right at the top will open it when you push it.