Are Circuit Pen's as useful as they sound? I'd like to create my own
circuit boards. Since I'm just learning and only doing one-offs, I'd
prefer to keep the total cost down. Are they "good enough" to do full
circuit boards, or are they mostly for repairs?
Are there brands that are a better value than others? How well does
soldering on them work?
Are they typically fine enough for SMD work, such as ATMega328 (0.8mm
lead pitch)?
They *may* be useful for repairs (read some of the reviews over at
Amazon for an example of the class) but they would be hell trying to use
to make an original layout for anything with a fine pitch.
<
http://www.amazon.com/CircuitWriterTM-Precision-Pen-silver-based-grams/dp/B0002BBVQO>
You'd be better off getting something like
<
http://microcontrollershop.com/product_info.php?products_id=4753>
that takes care of the housekeeping (power supply, I/O drivers, etc.)
and offers a prototyping area as well as I/O headers or the simpler
<
http://microcontrollershop.com/product_info.php?cPath=110_159_339&products_id=4429>
that's just a "header board." With either, you can access the processor
pins for digital I/O, ADC, PWM, or whatever from relatively robust
headers out to your own circuitry.
If you want to roll yer own, do it properly by starting with a schematic
capture program that produces a "net list" to be used by a PCB layout
program. That then makes the "Gerber" files and the drill file that a
board house can use to make the real thing.
Kicad is a free (libre and as in beer) integrated package for Windows
and Linux that includes schematic capture and PCB layout.
<
http://www.kicad-pcb.org/display/KICAD/KiCad+EDA+Software+Suite>
If you're on Linux, also look at gEDA <
http://www.geda-project.org/>
There are also "free" tools offered by various board houses but some
(most? all?) of those generate a proprietary output, not standard
Gerbers, so you're stuck with one vendor.
While many people do still make boards in the kitchen, using techniques
like Press'n'Peel Blue or photo-resist, the cost of manufactured boards
has come way down. Especially when doing fine pitch and surface mount,
you will appreciate having a proper finish on the pads and having a
solder mask. Sparkfun and Seeed Studio (among others, these are the ones
I'm familiar with) have very low cost batch proto board services. There
are also traditional houses (e.g., Sunstone) that do inexpensive
prototypes at a faster turn but there is some added cost associated with
the speed, of course.
<
https://www.batchpcb.com/> associated with Sparkfun
<
http://www.seeedstudio.com/depot/fusion-pcb-service-p-835.html?cPath=185>
will do ten 2" x 2" boards for $10. A buck a board!
<
http://www.sunstone.com/> a more traditional board house that offers
turns measured in days instead of weeks but also with more traditional
pricing
