How do you design these days?
in [Design]
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From: Jim Thompson on 31 Dec 2009 18:06 On Thu, 31 Dec 2009 14:54:10 -0800, Joerg <invalid(a)invalid.invalid> wrote: >Jan Panteltje wrote: >> On a sunny day (31 Dec 2009 14:12:03 -0500) it happened DJ Delorie >> <dj(a)delorie.com> wrote in <xnws039cvw.fsf(a)delorie.com>: >> >>> My way is to use a solderless breadboard, but build up sub-circuits on >>> home-brew PCBs. So I've got a USB adapter, MCU adapter, ethernet >>> socket with discretes adapter, power supply boards, etc. Homebrew can >>> whip up a whole panel of breadboard adapters for SOT TSSOP CSP etc in >>> little time and at little cost. The breadboard is for interconnecting >>> the modules, adding pullup/pulldowns, etc. Once the circuits are >>> explored this way, it goes to a PCB fab as a single final board (no >>> production runs for me, just a hobby) and if it doesn't work I hack it >>> until it does. >>> >>> Here's an example of that process (scroll down to the breadboard >>> pics): http://www.delorie.com/electronics/alarmclock/ >>> http://www.delorie.com/electronics/alarmclock/20070723-proto.jpg One >>> project, nine adapter boards (ten when you include theftp://panteltje.com/pub/z80/graphics_card_top.jpg second OLED >>> connector), one breadboard. >> >> Real man use no PeeSeeBee: >> ftp://panteltje.com/pub/z80/graphics_card_top.jpg >> ftp://panteltje.com/pub/z80/graphics_card_bottom.jpg >> :-) >> > ><GASP> > >I think I am going to get sick ... SOS: System on a ..... shingle ?:-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | "You cannot help the poor by destroying the rich. You cannot strengthen the weak by weakening the strong. You cannot bring about prosperity by discouraging thrift. You cannot lift the wage earner up by pulling the wage payer down. You cannot further the brotherhood of man by inciting class hatred. You cannot build character and courage by taking away people's initiative and independence. You cannot help people permanently by doing for them, what they could and should do for themselves." -Abraham Lincoln
From: krw on 31 Dec 2009 18:21 On Thu, 31 Dec 2009 13:13:57 -0800, Joerg <invalid(a)invalid.invalid> wrote: >krw wrote: >> On Thu, 31 Dec 2009 09:10:22 -0700, Don Lancaster <don(a)tinaja.com> >> wrote: >> >>> John Larkin wrote: >>>> On Thu, 31 Dec 2009 14:01:44 -0000, "markp" <map.nospam(a)f2s.com> >>>> wrote: >>>> >>>>> "RogerN" <regor(a)midwest.net> wrote in message >>>>> news:ROudnXLvg9-Tm6HWnZ2dnUVZ_oidnZ2d(a)earthlink.com... >>>>>> When I was in school components fit on solderless breadboards and we made >>>>>> circuits using breadboards, power supplies, meters and oscilloscopes. >>>>>> Many of today's components don't appear to be breadboard friendly, so how >>>>>> is it done today? >>>>>> >>>>>> Is circuit design software and simulation good enough to go straight to a >>>>>> PC board? Or do you use surface mount to breadboard adapters? Do you >>>>>> still use a soldering Iron to solder or paste solder and an oven? >>>>>> >>>>>> I'm wanting to tinker with some circuits but some chips I'm interested in >>>>>> only comes in MSOP or other packages that look intimidating to attempt to >>>>>> solder. >>>>>> >>>>>> Thanks! >>>>>> >>>>>> RogerN >>>>>> >>>>>> >>>>> I tend to design a PCB with CAD software then have prototype PCBs made. >>>>> There are several companies out there who do 'pooling', i.e. they amalgamate >>>>> many designs onto one PCB, that way you end up only paying a small fraction >>>>> of the tooling cost of the PCB. Some companies can handle 6 layer boards >>>>> with this process. Example in the UK is PCB Snap from Spirit Circuits >>>>> (www.spiritcircuits.com). >>>>> >>>>> This can be quite cost effectve for producing protptypes that are as close >>>>> to the final product as practicable. >>>> Why not go for the real thing, first time? If you get it right, you >>>> can sell it. >>>> >>>> John >>>> >>> It is NEVER right the first time. >> >> Some people evidently get close enough. If you don't try to get it >> right on the first time you never will, though. The problem is when >> management expects to get it right on the first try, ... > > >Very common situation when you are a consultant. New client, first >article should have shipped a couple months ago but it still doesn't >work. Everyone shaking in their boots. _Then_ your phone rings, >agreement is signed same day, you call off any and all birthday parties >and whatnot and you've got exactly one shot to get it right. > > >> ...then demands it on the second. About the fifth... > > >They'd have me over the barrel :-) The real problem is when they want it fixed, without changing anything. That's when the real churn starts. Compliance added another to a recent design because nothing could be changed in a previous "fix". Risk avoidance can itself be risky.
From: krw on 31 Dec 2009 18:29 On Thu, 31 Dec 2009 12:18:44 -0800 (PST), "nuny(a)bid.nes" <alien8752(a)gmail.com> wrote: >On Dec 31, 8:10�am, Don Lancaster <d...(a)tinaja.com> wrote: >> John Larkin wrote: >> > On Thu, 31 Dec 2009 14:01:44 -0000, "markp" <map.nos...(a)f2s.com> >> > wrote: >> >> >> "RogerN" <re...(a)midwest.net> wrote in message >> >>news:ROudnXLvg9-Tm6HWnZ2dnUVZ_oidnZ2d(a)earthlink.com... >> >>> When I was in school components fit on solderless breadboards and we made >> >>> circuits using breadboards, power supplies, meters and oscilloscopes. >> >>> Many of today's components don't appear to be breadboard friendly, so how >> >>> is it done today? >> >> >>> Is circuit design software and simulation good enough to go straight to a >> >>> PC board? �Or do you use surface mount to breadboard adapters? �Do you >> >>> still use a soldering Iron to solder or paste solder and an oven? >> >> >>> I'm wanting to tinker with some circuits but some chips I'm interested in >> >>> only comes in MSOP or other packages that look intimidating to attempt to >> >>> solder. >> >> >>> Thanks! >> >> >>> RogerN >> >> >> I tend to design a PCB with CAD software then have prototype PCBs made. >> >> There are several companies out there who do 'pooling', i.e. they amalgamate >> >> many designs onto one PCB, that way you end up only paying a small fraction >> >> of the tooling cost of the PCB. Some companies can handle 6 layer boards >> >> with this process. Example in the UK is PCB Snap from Spirit Circuits >> >> (www.spiritcircuits.com). >> >> >> This can be quite cost effectve for producing protptypes that are as close >> >> to the final product as practicable. >> >> > Why not go for the real thing, first time? If you get it right, you >> > can sell it. >> >> > John >> >> It is NEVER right the first time. > > You're getting a bunch of replies from naysayers who have gotten it >"right" the first time, but AFAICT mostly from people who have done >projects or one-offs. "Projects?" "One-offs?" > In the world of production though, that's the exception rather than >the rule IME. Even if the circuit does exactly what you first >daydreamed it could do without a single glitch, even if whoever etches >the board doesn't wire a pot backwards (I've had that happen), at some Backwards pots are code changes. ;-) (we use shaft encoders for pots). >point in the product development cycle somebody will alter a spec just >enough so that just enough redesign is required that your baby needs Spec changes don't count. That's management's fault. ;-) You do point out one of the main pitfalls, though. A good spec is critical to getting success out of the first board. Changing the rules after the game starts is cheating. >Frankensteining. It might be you didn't include enough LEDs for the >required "ooh, shiney" level, the case design asshat^H^Hartists >decided the air vents are in the wrong places, IME the sheet metal always gets done before the circuits. The sheet metal fixes the number of blinkin' lights and fancy knobs pretty well. >it has to go "boop" >instead of "beep" when junior feeds it a PB&J, or whatever. Code. > SOMEBODY will find a reason it needs "fixing". "Whenever more than one person is involved in a screwup, blame will never be placed." Or "The first to blink, loses." BTDT, it's no fun.
From: Jan Panteltje on 31 Dec 2009 18:37 On a sunny day (Thu, 31 Dec 2009 14:54:10 -0800) it happened Joerg <invalid(a)invalid.invalid> wrote in <7q4ocpFid2U2(a)mid.individual.net>: >> Real man use no PeeSeeBee: >> ftp://panteltje.com/pub/z80/graphics_card_top.jpg >> ftp://panteltje.com/pub/z80/graphics_card_bottom.jpg >> :-) >> > ><GASP> > >I think I am going to get sick ... Have to point out that that worked without a single problem for > 10 years. And it will likely still work if the EPROM has not lost data. But it has been superseded by better tech. You are not afraid of soldering some wires no?
From: John Larkin on 31 Dec 2009 18:37
On Thu, 31 Dec 2009 11:49:37 -0800, Joerg <invalid(a)invalid.invalid> wrote: >John Larkin wrote: >> On Wed, 30 Dec 2009 20:02:02 -0800, D from BC >> <myrealaddress(a)comic.com> wrote: >> >>> On Wed, 30 Dec 2009 20:01:39 -0600, "RogerN" <regor(a)midwest.net> >>> wrote: >>> >>>> When I was in school components fit on solderless breadboards and we made >>>> circuits using breadboards, power supplies, meters and oscilloscopes. Many >>>> of today's components don't appear to be breadboard friendly, so how is it >>>> done today? >>>> >>>> Is circuit design software and simulation good enough to go straight to a PC >>>> board? Or do you use surface mount to breadboard adapters? Do you still >>>> use a soldering Iron to solder or paste solder and an oven? >>>> >>>> I'm wanting to tinker with some circuits but some chips I'm interested in >>>> only comes in MSOP or other packages that look intimidating to attempt to >>>> solder. >>>> >>>> Thanks! >>>> >>>> RogerN >>>> >>> My motto: >>> If it works on a breadboard, it's not worth producing. >>> >>> On my current project, I have to feed the simulator pcb parasitics and >>> component parasistics to get accurate simulations. >>> I've had to bench test to get some parasitics. Once parasitics are >>> included, scope results and simulation results get close. >>> >>> If all looks good on sim, I make a pcb, etch it and bench test it. >> >> One problem is that device models often aren't available for fast >> parts, or all you get are S-params when you need large-signal >> time-domain stuff. So sometimes you can learn a lot by hacking some >> FR4 and testing parts. >> >> I never breadboard entire products, or even complex circuits... just >> enough to characterize parts or simple subcircuits. >> >> This is an EL07 driving a PHEMT... >> >> ftp://jjlarkin.lmi.net/BB_fast.JPG >> >> which made decent 5-volt, 1 GHz square waves. >> > >How do you get those nice clean cuts into the copper? Just x-acto. The magic trick is to then rub it hard with a Scotchbrite pad. That removes the burrs. John |