Lecture 13: April 17, 2013
Assignment: Make a board with an output or output device. Program it to "do something".
Lecture Notes:
I made two boards; the single-sided Charlieplexing LED array (hello.array) and the Unipolar Steppermotor Controller (hello.stepper)
Programming the boards were done from the commandline in Win 8 using avr-gcc and the FabISP (here identified as "usbtiny").
Command prompt: Programming the hello.array
Here is a video (H.264 avi format) of the working hello.array Charlieplexing LED board..
"hello.stepper" doing full steps
Despite considerable effort to keep the red and the green LEDs seperate during stuffing and soldering the hello.array-board, I ended up having two rows mixed up (each one single "line" of LEDs of the same color instead of the intended alternating pattern of red and green. So I had to shuffle those around. I did this very quickly by turning on both our soldering irons - and "grabbing" the LEDs while the solder flowed and lifting them off board with the soldering iron tips - one in each hand. A nice dexterity test. AND I saved several millimeters of desoldering braid...
I also had a nonworking hello.stepper board the first time. The problem was apparently that the wires from the battery were a bit to thick to let the IDC connector close properly.
I am now looking for a power supply to drive a larger unipolar stepper that I bought (cheap as chips) at the fleamarket at Waterlooplein in Amsterdam. Since the hello.stepper can drive up to 1.7A at 30V - I have to hook up the stepper to a PSU in the Fablab at see and which voltage I am close to but below 1.7A.