Bigger project design - Page 1
Forum section: electronics / beginners

author: jsi
author_rank: Regular Contributor
timestamp: August 01, 2016, 09:52:12 pm
content: I've got this idea - famous last words for sure. Right now it fills 2 breadboards and a third and a fourth may be needed before it's done. Then I'm going to want to make a PCB and maybe even sell a few. Some of the chips are only available as surface mount and the jumpers and resistors and diodes and inductors and, and, and, are bringing new meaning to word spaghetti.I can't help thinking there's got to be a better way. I don't for a second think the professionals build their projects on breadboards, so what do they do? Is there a hobbyist friendly software that lets one design circuits on the computer?

author: ataradov
author_rank: Super Contributor
timestamp: August 01, 2016, 10:00:14 pm
content: Depends on how you define "professional".At some point, when you have parts of your circuit established, it makes sense to make a partial PCB. Make it pluggable into a breadboard if you still need to do some prototyping.It is very rare that you actually need to prototype everything. Usually "professionals" can get a decent first pass at digital stuff straight in the CAD, especially for stuff that works on a breadboard. Sometimes you need to prototype analog things, but even then, you can make a PCB with prototyping area.

author: rs20
author_rank: Super Contributor
timestamp: August 01, 2016, 10:14:52 pm
content: +1 -- I'm no professional, but building an entire system on breadboard hasn't crossed my mind for a long time now. As I see it, there's still a finite chance of making errors on first pass of the PCB (no matter how polished your breadboard design is), so it's a fool's errand to go to massive effort prototyping on breadboard. But of course, that depends on your level of confidence (/arrogance?), and the nature of what you're working on. Side note: the most interesting parts these days are SMD-only, so you don't even really get a choice.If I ever did do breadboard work, it'd be to verify assumptions in certain blocks of the circuit -- hence I'd only be building that one part of the circuit. Unless you're building some strange circuit with a giant feedback path looping around the entire circuit, there's no point in building it up all at once.I also +1 the suggestion of building subparts of your circuit as smaller PCBs, if you still want to build the whole thing with breadboard parts.

author: spacedementia87
author_rank: Contributor
timestamp: August 01, 2016, 10:27:32 pm
content: You can use Eagle PCB to draw schematics and PCB designs.It is free and quite powerful. SparkFun have some very good tutorials on how to use it.Producing the PCB is harder though most fabrication labs are expensive (£40 each) for small batches. If you want to test out a design though you can use thicker traces and you can use a toner transfer method to print in the board.If you are selling the same fab houses prices come down very steeply as you order larger batches. They might be £40 for one but £200 for 100.There are also some Chinese places on Ali Express that seem to offer £13 per board for a double sided PCB drilled. Seems pretty cheap but I have not used one ever so don't know what they are like.Sent from my ONE A2003 using Tapatalk

author: ataradov
author_rank: Super Contributor
timestamp: August 01, 2016, 10:30:27 pm
content: Use OshPark for prototypes, don't pay £40 per board.

author: tautech
author_rank: Super Contributor
timestamp: August 01, 2016, 10:41:13 pm
content: Quote from: jsi on August 01, 2016, 09:52:12 pmNot that I'm familiar with it but you will see Spice circuit simulation mentioned a lot in the forum.A search for Spice finds 21 pages of results.That there's no sticky threads on circuit simulation is disturbing or have I missed it.

author: dmills
author_rank: Super Contributor
timestamp: August 02, 2016, 01:32:43 am
content: My general experience is that usually most of a circuit will clearly work as designed, no need to breadboard or sim when it is jellybean stuff.Sims are useful when you have complex loop dynamics or filters you want to quickly verify, and Manhattan style is good for prototyping small signal analogue and medium speed RF sections.You will fairly quickly learn which things a sim can be trusted for, and when be suspicious.Other then that, straight to a pcb, and often straight to a short run at the assembly house, the better to catch paste mask errors and incorrect solder mask expansion (Design and schematic reviews are a good thing before going here).Now I do this professionally and a week spent building up a prototype has direct costs of my time about the same as sending the thing out and getting a few made on a pick and place line, and opportunity costs higher then that if the sales crew are doing their jobs.

author: tautech
author_rank: Super Contributor
timestamp: August 02, 2016, 02:51:27 am
content: Spurred by this thread I started another:https://www.eevblog.com/forum/beginners/circuit-simulation-(sticky)/