From breadboard to perfboard

Hi,

I need to build a set of 8 pushbuttons with built-in LEDs. After messing around with breadboards I'd like to make something more permanent. After laying out the base components on a perfboard and drawing some lines in Photoshop, I got a bit overwhelmed by the potential mess of wires (cf. photo).

Admittedly very simple, this is my first "serious" circuit. But the number of wires dangling from the back promises to be quite large... I'd appreciate some advice from those who've already built some: how to avoid a total mess behind the perfboard, how to optimize layout etc. Maybe there are some "helper" components I should know about?

Thanks a lot.

Think about running the horizontal and vertical parts of the paths on two different sides of the board.

Things can get to looking messy but still be OK from an electrical standpoint. Here are a couple recent threads along similar lines. BTW, interesting buttons, where did you get them?

http://arduino.cc/forum/index.php/topic,110347.0.html
http://arduino.cc/forum/index.php/topic,110462.0.html

It's funny, I showed a button like that to a guy in an electronics shop, and he said, "Great looking buttons, where did you get them?"...

Actually they were 20 for two euros at an electronics shop counter in Paris (France). While looking for specs I did a Google Image search for "LED pushbutton" and found a site with something similar here. The ones I have look a lot like the one on the bottom right, except the LED is red and not orange.

Small issue: they're not really perfboard or breadboard friendly — as the LED contacts are off-center you have to twist them slightly to make them fit (cf. photo). I really don't know who's responsible for this...

Can't be more specific I'm afraid.

Sparfun has some that looks the same

20 for €2? That's insanely cheap! You have no idea how lucky you were to find them at that price; the only similar thing I can find is €1.54 each!

I know, I wanted somewhat bigger LED-buttons but they starting at 4€ apiece... so I settled with those, which are really small BTW (i.e. not really ideal for prolonged use with adult fingers).

I got one of these the other day. That's bigger ...

Cheap parts of all kinds can be found at Electrodragon, I was Blown away at some of the prices.... locking PB switches for $0.05 -$0.10 Ea... I just spent about $50.00 there, went nuts. Check This out
http://www.electrodragon.com/?product=3-2-tft-lcd-arduino-adapter-shield

Doc

Getting back to the original thread topic... Neat Switches BTW and a Nice looking place to shop, especially if one was thinking about opening up a little shop... The real issue with your layout is that it 'looks?' like you literally wired it pictorially instead of pictorially wiring it literally. The "literal" method is to place the parts as close together as use and wiring limitations apply. Obviously one wouldn't wire pushbuttons any closer than a keyboard or IC's and other parts any closer than wiring complexity and size limitations dictate but there is in your layout, as neat as it is... a great deal of 'air', wires that longer than strictly needed and the IC a lot farther away than easy wiring would permit. I do admire the switches but think that I would have wired it a little tighter together as it does complicate replication. IMO

Doc

@Doc: thank you for the suggestions. Like I said, first "serious" circuit, and it will be even more complex when I'm done with it (another HC165 in cascade with 8 more switches in a 2x4 arrangement). There is "air" between the switches because, like I wrote above, they are quite small and to keep the entire thing useable I need to account for real fingers.

I'm still confused about one aspect of the actual soldering process. In the Make: Perfboard Prototyping video, on the bottom side of the perfboard connections are made using solder only. Wires, on the other hand, are used on the top side. I was thinking of running wires at the bottom side because I have 3 16-leg ICs and I can't possibly smear my entire perfboard with solder and make it out alive.

So, any "best practices" out there (apart from the layout itself, which I'll optimize further of course)?

I use the top for the wires and the bottom just for the tracks. Try and make the top wires horizontal or vertical. That way you can use tinned copper wire with no insulation and it looks neat. Use the copper tracks on the underside to bring the connections to a point where these links can be made. You won't be able to do all the connections like this but it should minimise the "mess".

This perfboard doesn't have copper tracks on the underside, I only have copper circles around each hole. Are you suggesting that I create "tracks" with solder?

Since I'm somewhat overwhelmed by this, I've drafted a quick preview in OmniGraffle (cf. attached screencap) which makes it easy to rearrange stuff. In no way can I imagine a solution suggested by @marco_c, i.e. separating the vertical and horizontal paths. Whatever I do, from a topological point of view the wires will always be crossing, and I haven't even started to draw the wiring of the second half (on the right) — which is arranged differently but still a disaster waiting to happen.

Should I keep the wires "floating" on the backside, like a small jungle?

I have wondered many times how in the hell people can design complicated layouts. I am a Linux user, and have used the gEda package before. Anyone have any tips on using the layout tool in gEda? Will it actually help you decide the best layout, or is it just a glorified autocad for circuits? I have never even tried it since I have only taken one project from the breadboard to pcb and I just jumpered all the connections because I could not wait to have a working unit. Next time I'd like to do it right.

Eagle lets you do some pretty complicated stuff. Just keep throwing stuff on the board until it breaks!
This all fit in a 10cm x 10cm board with components on 1 side.

It all comes down to careful parts placement to cut down on vias & traces that have to cross each other.
And good use of the ground planes.

Within limits the connectivity determines the layout. A working design will go to a pcb virtually without change with the exception of the power supply Frequently the overlooked Item Power traces should be as wide as routing the board will accept. By pass capacitors should be used. a .1uF cap/ic works well and if an onboard regulator distribute 100 300 uf in smaller capacitors. The last suggestion would be to do a "Copper Pour" and tie it's net to Ground and re-pour the net to include the ground points present in the netlist for the board. Finally whether hand or machine routed the same rules apply.
The 'rules' I mentioned are only common sense and it is also common sense to route inputs to devices away from outputs and to route inputs away from power supply wiring. In the work I did which which was mostly mixed signal analog and digital circuitry split power supplies were necessary including switchers and those were placed at one end as far away from the inputs as physically possible and rc filtering was frequent done with 2 - 22 ohm resistors and 1 - 10uF bypassing before and after the filter resistor. This is done to "split " the Vcc supply line up so as to present a good low impedance Vcc source to all IC's. If your design only has 1 IC then follow the scheme used on the UNO board.
Experience is the finest teacher. When I began my designs lacked those things, were simple and worked mostly.. I was fortunate to begin with small boards with 2 - 3 - 4 IC's as the things I mentioned above came to me slowly. Frequently a circuit is designed from the function and data sheet pinout of the device and works great and little attention is ever spent in reading the design notes. This is where one learns the virtues of the simple things I mentioned above.
This is where the real engineering begins. Where one learns that design notes are an engineers best friend. Where cation and conservative thought will make the difference in how and with what a design will work with.
Batteries are a designers worst enemy. As they become depleted their internal resistance increases and this is one example of the mention of attention to power management is so important to a working design.
And Finally a successful design will work under all conditions. Develop your own power supplies and only share ground and I/O with the Processor. You will loose a major part of any noise or analog voltage dependent measurement in accuracies. If an analog or any other circuit requires any supply voltage you supply it don't depend on loading the processor with your stuff/ Finally unless otherwise possible If you have an input going off board, terminate it, pull it up or dowm and let the next board do the pull ups and downs Never send a floating input or output off board, one cannot assume that the "other Guy" did his home work too.
A good design works all of the time under any circumstances and with any equipment connected to it. It will be stable in a known state and be ready to connect and use or just use when connected, unconditionally. That is when I signed my name to a design... Only.

Doc