Making more boards, and writing a little code....
This week, I had the usual assortments of things
taking longer than I thought they would.
Accomplishments:
- Late night panic, and developed a general purpose ATTINY44 board
that is based off of the FABISP.
- Developed a plugin light/switch paddle board for the above.
- Wrote/burned a little code to make the LED's do something.
- Got my GPIB plotter working, making PCB's and etching.
- Drew up a revised fabuino board with a ATMEGA169 (that has a
short)
- Tried more casting with the shaft coupler, gears, and pen holder
of last week in urathane.
ATTINY44 General Purpose PCB
I wanted a board that I knew would work, so I modified the
fabisp board to break out all of the pins on a header, put on the PCB
usb connector, and a programming connector.
![eagle_layout](../../Assign5_AVR/handin/eagle_board.png)
And assembled....
![Gen purpose ATTiny44 board](allworking.jpg)
Attached to that board is a LED breakout board with a
button. This could be swapped with other boards with other
types of functionality. It is shown with a little code to
blink some LED's.
![light_board](lightboard.jpg)
Fabuino Mega168 Board Attempt
Assembled, but there is a short on the reset line.
Will need to debug. Time to spend more quality time
with the microscope!
![fabuino](fabuino.jpg)
Making PCB's
Much of my time was spent trying to remember how I
used to make circuit boards on an old pen plotter, and experimenting to
see if I could make boards of comparible pitch and quality to those
produced on the modella. This would have two advantages--
the process can be faster, especially for larger boards, and I wouldn't
have to spend late nights at the lab making boards.
Unfortunately, the PC I had that would talk
GPIB to the plotter, decided to finally die. After some
fighting I upgraded it form a 386sx to a k62-233 (I needed an ISA
bus)! Woohoo...
The process is as follows:
1. Scrub board with brillo.... ![brillo rocks!](brillo.jpg)
2. Plot board...![plot_board](plot.jpg)
3. Mask areas, and touch up artwork...
![mask board](light_before_etch.jpg)
4. Play with fun chemicals... (FeCl) The board is in a
ziplock freezer bag, and I swish it under hot water in the sink for
about 3-5 minutes.
![Doin Acid....](fecl_bath.jpg)
5. Scrub the resist off with brillo, and populate! (See
above)
Results:
I was getting pitting on the
etches. I think it may be due to using a blue pen
instead of a black pen--places I touched up with the black pen eld up
much better.
Casting with Urathane
I tried casting parts with Alumalite (white) hoping that I could
machine, drill and tap them. Turns out I should have
mixed the bottles better. The first parts came out a
little soft, the latest batch came out foamy because I shook the bottle
before mixing. The finished surfaces on the foamy
parts came out ok, but they foamed up on the back side of the
part. Try, try, again!
![cast_parts](alumalite.jpg)
Notes on Embedded Programming Assignment
In the FABISP
makefile, there is a change required to use the FABISP instead of the
Atmel one.
Under the microscope, I could see a sketchy connection
(and maybe I forgot to install a jumper) so both programmer boards now
function!