74 Nicolas Collins
Rule # 18: Always leave your original breadboard design intact and functional
until you can prove that the soldered-up version works.
This makes it much easier to debug any mistakes, by comparing the working
version on the breadboard with the miscreant on the circuit board.
Be careful not to make unintentional “solder bridges” between traces when
soldering. (After transferring your first design to a circuit board you will see
how important it is to have a good soldering iron with a very fine tip.) Compare
your connections against the breadboard one more time before connecting the
battery and turning on the circuit. If the battery or chip get hot when the circuit
is on, shut it off immediately and check again for mistakes.
If the circuit makes sound, but is quieter than the breadboarded version or just
acts weirder than it should, check to make sure you remembered to hook up the
battery’s + and - connections to pins 14 and 7 of the chip -- sometimes the circuit
almost works without a direct power hookup, by sucking voltage through other
connections you have made (spooky!). Another tip for keeping this (and all
other) circuits running cleanly is to solder a 0.1uf capacitor between the + pin
(14) and the - pin (7), keeping it as close to the pins as possible (not at the other
end of the board and linked by wires.)
A circuit board that mirrors your breadboard exactly makes the transfer process
much easier. If you can’t obtain such a board you must make adaptations
carefully, checking you connections as you go. Once you have transferred a few
designs, and get comfortable with the “topology of circuitry,” you can choose
various sizes and patterns of circuit board that give you the freedom to re-
arrange your design between prototype and final version. Larger boards can be
cut into smaller sections for simple one-chip circuits like our first oscillator.
When your circuits start to get complicated you may find that regular hookup
wire gets thick and messy on the board. If you want to lighten up, and move
from spaghetti to capellini, buy yourself a roll of what is called “wire wrapping
wire.” At 30 awg gauge, it’s real thin, stays in place when snaked around the
board, and comes in nice bright colors.
Once you’ve confirmed that everything works you can move on to finding a box
and drilling a mess of holes (see Chapter 17.) Have fun!