PCB

Make vs. Buy

Advantages of PCBs Circuitry built on custom boards is sturdier, more stable, and more compact than the same electronics strung together by hand. And since it takes less time to assemble, PCBs are also better for making multiples. They’re cheap and easy to prototype, and you can find a variety of templates and projects online.

You can order custom PCBs ^{Process Overview
through design houses, but We’ll design our printed circuit on the computer,} as a plain black-and-white image. Black represents
they are expensive — and the where we want the board to have copper connec-
_{per-unit cost is especially high} tions between our circuit’s components, while the _{white background corresponds to areas of plain,}
for small batches. Also, when non-conducting fiberglass. Then we’ll print the
_{you change the design, a shop} design onto special transparency film and iron it _{onto the copper side of a blank PCB (which starts}
will typically take several days out with copper completely covering one side).
to turn it around. Since it’s nor- We peel the film back off, and the printed design
remains on the copper. Next, the magic happens:
mal for a board to go through when we bathe the board in an etching solution,
several revisions, this adds up copper dissolves away in the blank areas of our
design, leaving conductive “traces” behind where

to a significant delay. we had drawn the circuit’s connections. After this,

we prepare the board for soldering, then finally go to town with the components.

MATERIALS: TOOLS:
TECHNIKS PRESS-N-PEEL SCOURING PAD
PCB TRANSFER FILM (do not use steel wool)
(20 sheets for $30),
techniks.com

Broken down step-by-step, the entire process can be summarized as follows:

PHOTOCOPIER OR LASER PRINTER

1. Create the design.
2. Print or photocopy the design.

AMMONIUM PERSULFATE

3. Prepare the PCB.

CR YSTALS (1Kg for $20), ELECTRIC CLOTHES IRON

mgchemicals.com

4. Transfer the design to the copper.
_{HARD WOODEN BOARD} 5. Check and correct the traces.

BLACK CORRECTION PEN 6. Etch the board.

(Lumocolor or LARGE POT AND PLASTIC _{7. Clean and drill the board.} fine-tip Sharpie) TRAY for etching _{8. Solder the components.}

PCB COPPER BOARD HIGH-SPEED DRILL
(9 x 12 x 0.062-inch, 1 AND BITS
oz., single-sided, $12),
techniks.com SOLDERING MATERIALS

CIRCUIT COMPONENTS

PERF BOARD AND WIRE (OPTIONAL) for prototyping

NOTE: Techniks Press-n-Peel transfer film is a reasonable compromise between ease-of-use and cost. You could mask a board for etching with just a permanent marker, but this would take a long time, and it would be extremely difficult to make the lines sharp and accurate enough.

TIP: PCB design houses are well worth the price if you have a finished layout. But if your project is relatively simple, or the design is still evolving, then making your own PCB is the way to go.