What techniques are useful when layout a circuit on a breadboard? Specifically, making it as least cluttered and readable as possible. My circuits always come out looking horrible and really messy.
Is there a technique on where to start? Or some rules on what to connect first?
Look at the breadboard view of Fritzing.
I have never bothered with a complicated circuit on a solderless breadboard. It's usually less trouble to just start soldering things together on a 0.1" protoboard.
Breadboards are best for quick, small "will this work" circuits. And who cares if those look a bit messy.
Plan it on paper first or by using a CAD program
Decide on the optimum position for your ICs, keeping signal lines short. Use the centre, empty track to your advantage. See that power and ground is necessary wherever needed.
Connect power and grounds first, then signals.
Modularise your circuit: build the pre-amp, then the oscillator, the the microcontroller (or whatever your circuit uses) in distinct sections: even better on separate boards.
General cleanliness:
Clip wires to short lengths keeping insulation on them right up to the sockets. Ideally, use a dedicated wire stripper tool, as that gives cleaner results.
Clip component lengths short.
Use the bus lines for carrying power or commonly used signals
Use DIP sockets for DIP packages.
Find a size wire (usually 22 or 24 guage, but insulation thickness matters too) that fits the breadboard nicely. Ideally you will have multiple colors. Old multipair telecom/network cable can sometimes be a source.
Place all chips the same side up
Don't wire over chips. Space them a few rows apart so you have a wiring channel between them. Make horizontal runs between the power busses of one breadboard unit and the next below (if you have double busses)
Route and bend wires deliberately. Solid core wire will stay where you put it if you shape it firmly (don't use the stranded wire with end pins except maybe for jumpers you will move in operation)
Tack wire bundles down. I've used short jumpers between two holes of the same power bus, and in one case even hot glue to the carrier board.
If you have 4 or 8 colors available, wire data busses in a spectral order. If two wires pop out you don't have to trace them, you already "know" which goes where.
If you have a resistor or a cap spanning any distance, use scraps of wire insulation on its leads
Get some white label stock and stick it on your chips, then using a fine mechanical pencil notate pin numbers or important pins, like > for the clocks, etc. Or you could probably laser print the whole pinout, like they used to sell...
You should have the pinout of 74xx series logic and buffers memorized anyway ;-)
When debugging, always check the power to each chip. They can confusingly "almost work" with a missing power lead but exhibit odd behavior. Also remember that many logic families will usually see an open input as a high - though your finger or a probe may change that!
