General Design Process Advice

So, after the successful completion of my last large project, which coincidently was my first proper design - which turned out very nicely in terms of functionality, PCB design etc - of which there were many a contribution in different sections of this forum - I am about to begin a much more complicated and larger design.

So, with this new project - I'm in the phase of putting together plans etc, and would like a bit of general advice / guidelines on the entire process, as the last project was a little 'amateur' in its' execution.

  • In terms of schematic capture, this time round - for each and every IC on the board, I'm building a checklist, outlining each pin and it's requirements to ensure they are all done correctly per pin
  • Regarding PCB design, component placement I feel needs more attention, there were more than a few sub-optimum traces on my last design, place, replace and replace
  • Documentation as a whole this time will be a large focus, ensuring each and every design step, test / verification is properly logged and documented
  • Budgeting much more thoroughly maintained
  • Proper time planning, monitoring and recording
  • Software flow charts
  • Schematic, software & PCB revision history, both in terms of files and a written revision history, etc.

I hope you get my train of thought, but in general am looking to complete this project in a much more professional manner - and I know there's more than a little bit of experience with some members on these forums...

All of my last projects were completed for personal means, or as part of my degree - whilst I also worked throughout my time at uni, I'm now embarking on a project at work for which I've secured support - and clearly, the entire process will be very different to the hugely unrealistic setting of academia...

Please, educate away!

Many, many thanks in advance!

You've got a pretty good list going there. Don't forget parts lists, material pricing, assembly pricing.
Create a schedule and put in dates for when everything is to happen, if there's an dependencies note those too. MS Project is good for that.
Any long lead items? Not too much takes more than 2-3 weeks to obtain anymore.

PCB design/placement - that just takes practice, your layouts will get better with time. Sometimes the choice of package makes a big difference too.

Start with a narrative of what the design is to do in both hardware and software, the board size goal, the enclosure, off board IO requirements, power connections, etc. Get some peer review on that before going too far. If someone comes along later and says "but it doesn't do this!" you have a requirements document to point to and say "hey, we all reviewed/signed off, you should have piped up before!". Don't let requirements creep screw your schedule, you'll have enough unplanned things to take care of already.

Any long lead items? Not too much takes more than 2-3 weeks to obtain anymore.

Not particularly - the only long'ish' leadtime items will be the bespoke enclosure designed as both exactly that, and the heat sink.

Regarding package choice - I know what you mean, I changed a few package choices in the last design to make routing much easier, SOIC --> QFP etc.

Get some peer review on that before going too far. If someone comes along later and says "but it doesn't do this!" you have a requirements document to point to and say "hey, we all reviewed/signed off, you should have piped up before!". Don't let requirements creep screw your schedule, you'll have enough unplanned things to take care of already.

This is a big one I feel, a lot of planning so far has been geared around matching our specs with competitors, exceeding in some places to target certain market sectors, perhaps not matching competitors in some areas where we don't intent on marketing too so much etc. Discussing with some of my contacts, what their customers' have enquired about / wanted in a product in the past certainly is helping...

Many thanks, your input has always been helpful in my threads!

Simulation software is useful. I use LT Spice
Free!
Linear Technology Corporation's LTspice IV

Yes, I use LT Spice IV too - I use EAGLE for design work, which exports straight to LT Spice now which is a nice addition!