Re: gEDA-user: SMD soldering challenge status
> > By showing phase instead of actual clocking, we avoid the need to > > have <60Hz frequencies. The LEDs would show the beat between them > > due to component tolerances, not the actual clocks. > >Now THAT is a fun idea! Ok, I prototyped this (yay radio shack electronics labs :) with two 0.01u/100k oscillators, each buffered, using up the hex inverter. The outputs went to D and C of the D flip flop, resulting in the oscillators changing too fast for the eye to see but the FF changing about 2-3 times a second. The prototype didn't use the extra inverters or transistors (i.e. all the SOT-* parts), but I can just chain those through the output to drive the 0603 LEDs. If we have a SOT-323-5 inverter, do we need a SOT-323 transistor? I don't think it would add anything to the challenge, and it's eight cents more to play with. If we can fit this on a single sided Olimex board, we're at $1.99 per board. If we need double sided, we can drop the SOT-23 (the biggest transistor) to stay in budget. I haven't tried to lay out the circuit in the 16x10mm space. Of course, the prototype was with 4000 series CMOS, not the schmidt triggered 74LVC inverters. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: SMD soldering challenge status
DJ Delorie wrote: Hmmm... make two free-running oscillators with the same parts, and hook two LEDS up between the outputs (one red, one green, in opposite directions) so the LEDs indicate phase. Or have one clock the D-FF, and the other provide the D input, use the Q and ~Q outputs to indicate phase. By showing phase instead of actual clocking, we avoid the need to have <60Hz frequencies. The LEDs would show the beat between them due to component tolerances, not the actual clocks. Now THAT is a fun idea! -Dave -- Dave McGuire Cape Coral, FL ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
gEDA-user: Cryogenic / Ceramic Substrate PCB Material?
Has anyone here ever done any work with cryogenic circuits? The application is some ultra low noise amplifiers. Does anyone know of which houses can make PCB's based on Ceramic Substrate Material? Would there be something better material to use in Liquid Nitrogen than Ceramic? http://www.interfet.com/ makes low noise parts for this kind of work, anyone know of other obscure companies? ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
gEDA-user: SO-28 follow up
Yesterday I posted a message regarding a failure in gsch2pcb when the footprint
contained the string "SO-28". It seems that any footprint beginning with "SO-"
will fail.
Attached are my test schematic and project files. I would appreciate feedback.
George
schematics so28.sch
output-name so28
v 20060123 1
C 1500 83600 1 0 0 pic18F242-1.sym
{
T 5300 89700 5 10 1 1 0 0 1
refdes=U1
T 6100 89600 5 10 1 1 0 0 1
footprint=SO-28
}
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Re: gEDA-user: analog switch idea
gene glick wrote: >> Sometimes it adds linearly. Sometimes it cancels. Good designs >> will use this cancellation to advantage. >> > How does that work? Take an opamp that is wired to amplify the difference of two signals. If both signals are affected by the same noise source, the noise will be absent in the output of the opamp. ---<(kaimartin)>--- -- Kai-Martin Knaak [EMAIL PROTECTED] http://lilalaser.de/blog ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: analog switch idea
al davis wrote: On Saturday 05 August 2006 09:46, gene glick wrote: Hey, I am curious, noise adds as the root of the sum of the squares, right? ..because it is uncorrelated. Yep, that's how I remember it :-) How does distortion accumulate? Seems to me that it just adds linearly. Sometimes it adds linearly. Sometimes it cancels. Good designs will use this cancellation to advantage. How does that work? I'd have to know, pretty well, the transfer function of whatever is causing the distortion. I can see using that to my benefit, but how else could this work? ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: SMD soldering challenge status
> Panasonic NP061A500A dual PNP with built in bias resistors is in a > package with a 0.35 mm pin pitch. $0.51 in 100's at Digikey. Is 350 > µm fine enough? ;-) I have down to 0.40mm pitch so far (the tvsop). The problem becomes finding cheap FABs at that pitch - 0.40mm is 7.89 mils, so we might have to go to a more expensive fab. 0.35mm is 6.88 mil, which might push us even further. If Olimex can do the 0.40mm pitch with their 8 mil rules, that's about $35 for the PCB. For 7 mil, we're up to $65 for the PCB, and at 6 mil it's about $70 (pcbbool) to $110 (4pcb) depending on how much sq in we need. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: gSchem Output
On 8/5/06, COMINT <[EMAIL PROTECTED]> wrote: Is it possible to output a schematic in pdf in colour?This will get you a .ps in color:http://www.geda.seul.org/wiki/geda:faq-gschem#how_can_i_get_color_postscript_png_output Then you can use gs to convert and merge multiple .ps files into one .pdf like this:gs -dBATCH -dNOPAUSE -q -sDEVICE=pdfwrite -sOutputFile=output.pdf *.ps- Taylor ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: analog switch idea
On Thu, 03 Aug 2006 22:38:25 + gene glick <[EMAIL PROTECTED]> wrote: > Any ideas? You might take a look on AD8110. I used them, and found very good. However it goues up till 200MHz, and it was designed for video. Levente -- http://web.interware.hu/lekovacs pgpYAlH9YOuNX.pgp Description: PGP signature ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
gEDA-user: gSchem Output
Is it possible to output a schematic in pdf in colour? Cheers ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: SMD soldering challenge status
> Does a Schmidt input inverter cost too much? www.digikey.com ;-) The tvsop is a hex buffer; if we swap that with a hex inverter it will be much more useful, and we'd have six gates to play with. The D flip flop can be set up as a divide by two. Hmmm... make two free-running oscillators with the same parts, and hook two LEDS up between the outputs (one red, one green, in opposite directions) so the LEDs indicate phase. Or have one clock the D-FF, and the other provide the D input, use the Q and ~Q outputs to indicate phase. By showing phase instead of actual clocking, we avoid the need to have <60Hz frequencies. The LEDs would show the beat between them due to component tolerances, not the actual clocks. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: SMD soldering challenge status
On Aug 5, 2006, at 12:56 PM, DJ Delorie wrote: If we did multiple transistors, they'd have to be different sizes (not a big deal) and you don't get the fine-pitch challenge with them, like you do with the mini-gates (SOT-323-5 and TVSOP). Panasonic NP061A500A dual PNP with built in bias resistors is in a package with a 0.35 mm pin pitch. $0.51 in 100's at Digikey. Is 350 µm fine enough? ;-) John Doty Noqsi Aerospace, Ltd. [EMAIL PROTECTED] ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: SMD soldering challenge status
Hi, On Sat, 2006-08-05 at 14:56 -0400, DJ Delorie wrote: > > The success of this circuit depends on what `low' valued means here. To > > get visual frequencies, for a couple of Hertz we might need between 0.1 > > and 1 microfarad or so. We would have to breadboard the circuit to find > > out appropriate values for the cross coupling capacitors. (Although > > probably not with those 01005 components... ;-) > > The least expensive ones are in the pF range. We can afford one or > two bigger ones, but we can't afford to make them all bigger. Plus, > you'll need a resistor or two, those are more also. > > If we did multiple transistors, they'd have to be different sizes (not > a big deal) and you don't get the fine-pitch challenge with them, like > you do with the mini-gates (SOT-323-5 and TVSOP). We could make an RC oscillator with the inverter, the kind that charges and discharges a capacitor from Vil to Vih and back again. We would need at least one inverter with hysteresis. The output of the first inverter would be driving an LED. Then another inverter could drive another led. Then the resistors could have larger values and the capacitors smaller values if the inverters are CMOS. Does a Schmidt input inverter cost too much? -- -- Mike Jarabek FPGA/ASIC Designer http://www.istop.com/~mjarabek -- ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
gEDA-user: Footprint Additions
I have made the following additions and changes to my footprint library which is at http://www.luciani.org/geda/pcb/pcb-footprint-list.html * Added Johnson Component shielded test jacks (129-0701-20x and 129-0701-30x) * Added Tyco Micro-Match Connectors (series 215079) * Added footprints for C&K Switches 7101SDAxx,7201SDAxx, 7101SDCxx, 7201SDCxx * Added footprints for Sumida CR75 Series Inductors * Added footprints for Bourns SDR0805 Series Inductors. N.B. The silkscreen on this part consists of two lines rather than a circle. The body diameter of this part is 7.8mm and the recommended pads consume an 8mm square. Rather than making a large circle (d>11.5mm) or short arcs I made two lines. * Added footprints for Coilcraft DC1012 Series Inductors. * Added footprints for Bourns Inductors SRU5028, SRU8028 and SRU8043 * Added footprint for On-Semiconductor SOT363 * Fixed the DIP footprints 1. Rounded pads are now on solder and component side 2. Increased the silkscreen to copper separation from five mils to ten mils * Changed all of the mounting holes to pins in IND__Toko_10EZ-Series Not all pin positions are populated for all varieties of the 10EZ Series. Also corrected the refdes position. (* jcl *) -- http://www.luciani.org ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: SMD soldering challenge status
> Yes - and think about being able instantly identify if the soldering was > successful or not by seeing the LED blink. 'Built-in diagnostics'... > That's at least worth another $.02? Definitely worth $0.02. Not worth $2.00. The trick isn't the circuit, it's the budget. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: SMD soldering challenge status
> The success of this circuit depends on what `low' valued means here. To > get visual frequencies, for a couple of Hertz we might need between 0.1 > and 1 microfarad or so. We would have to breadboard the circuit to find > out appropriate values for the cross coupling capacitors. (Although > probably not with those 01005 components... ;-) The least expensive ones are in the pF range. We can afford one or two bigger ones, but we can't afford to make them all bigger. Plus, you'll need a resistor or two, those are more also. If we did multiple transistors, they'd have to be different sizes (not a big deal) and you don't get the fine-pitch challenge with them, like you do with the mini-gates (SOT-323-5 and TVSOP). ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: SMD soldering challenge status
On Sat, 5 Aug 2006 09:34:20 -0400 DJ Delorie <[EMAIL PROTECTED]> wrote: > >Even just a little 555-based LED blinker or something would count > > as "functional" in this case, I think. > > 0603 cap = 1 cent > 0603 led = 7 cents > > Even the venerable 555 is too expensive in the small sizes appropriate > to this project (about $0.60). > > Now, if you can think of a circuit that uses a flip flop and some > inverters, plus low-valued caps (even resistors cost 3x what caps > cost), that might be feasible. Yes - and think about being able instantly identify if the soldering was successful or not by seeing the LED blink. 'Built-in diagnostics'... That's at least worth another $.02? John ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: SMD soldering challenge status
Hi, Perhaps a bit more low-tech, how about an astable multivibrator? This circuit needs 2 transistors, 6 (or 7) resistors, and two caps. Add two LED's and you have a blinker. We used to build these out of leaded components on a 1.5 x 1.5 inch piece of perfboard. We had students who were in grade 5 assemble these from loose components, and they all got the circuit to work. The circuit can be built in one layer if you allow a single trace underneath one of the components. On Sat, 2006-08-05 at 09:34 -0400, DJ Delorie wrote: > >Even just a little 555-based LED blinker or something would count as > > "functional" in this case, I think. > > 0603 cap = 1 cent > 0603 led = 7 cents > > Even the venerable 555 is too expensive in the small sizes appropriate > to this project (about $0.60). SOT-23 transistors come in at $0.10CDN at DigiKey in single unit quantities. > > Now, if you can think of a circuit that uses a flip flop and some > inverters, plus low-valued caps (even resistors cost 3x what caps > cost), that might be feasible. The success of this circuit depends on what `low' valued means here. To get visual frequencies, for a couple of Hertz we might need between 0.1 and 1 microfarad or so. We would have to breadboard the circuit to find out appropriate values for the cross coupling capacitors. (Although probably not with those 01005 components... ;-) > > (ok, so it's more than just a *soldering* challenge ;) -- -- Mike Jarabek FPGA/ASIC Designer http://www.istop.com/~mjarabek -- ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: analog switch idea
On Saturday 05 August 2006 09:46, gene glick wrote: > Hey, I am curious, noise adds as the root of the sum of the > squares, right? ..because it is uncorrelated. > How does distortion accumulate? Seems to me > that it just adds linearly. Sometimes it adds linearly. Sometimes it cancels. Good designs will use this cancellation to advantage. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: SMD soldering challenge status
>Even just a little 555-based LED blinker or something would count as > "functional" in this case, I think. 0603 cap = 1 cent 0603 led = 7 cents Even the venerable 555 is too expensive in the small sizes appropriate to this project (about $0.60). Now, if you can think of a circuit that uses a flip flop and some inverters, plus low-valued caps (even resistors cost 3x what caps cost), that might be feasible. (ok, so it's more than just a *soldering* challenge ;) ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: analog switch idea
Noise and distortion are my main concerns. The more stuff that gets in the way, the more it gets worse. Having said that, maybe the ADC distortion and noise is the worst - maybe not, have to look into that. I think I need to come up with a good noise budget and work from that. But it is hard to argue that the simpler the analog chain, the better - in terms of noise and distortion. Hey, I am curious, noise adds as the root of the sum of the squares, right? How does distortion accumulate? Seems to me that it just adds linearly. gene Many years ago I did some of that .. As I recall, the "analog switch IC's" are really mosfets, series or shunt. The distortion spec was made under certain operating conditions. Since you didn't say what you are using, or the circuit, I can't judge how to make it better. This type of switch works best at a virtual ground, so the voltage is zero or constant. Since it is used as a series element, the distortion can be minimized by using a larger series resistor. This makes the nonlinear part of the resistance a smaller part of the total. This may increase noise, which may or may not be an issue. You need a pair of switches, or a single-pole-double-throw, for each signal. You need to consider what happens during switching. Make sure that you never short the op-amp input to ground (which effectively removes negative feedback) and you never let the voltage get big. Either of these problems will result in a pop or click during switching. You also need to consider that distortion numbers usually increase as the signal gets larger. Running at a lower signal level will usually result in lower distortion. For the devices I used, the distortion was almost all second order, which is the least audible type. Considering all that, by the time all optimization was done, the performance impact of the switch IC was essentially zero. Its distortion and noise were masked by other distortion and noise in the system, and that was so low that the distortion was difficult or impossible to measure, and noise was essentially what has predicted by theory and dominated by other stages. I don't remember what brand or device we used. I do remember that it was mainstream and cheap. ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
gEDA-user: SO-28 Footprint
I created a footprint called SO-28. I then ran g2ch2pcb on a small test.sch file and it goes into an finite loop generating pads with the following error messages: stdin:5: /usr/bin/m4: Bad _expression_ in eval: (1028* - /2)/100 stdin:5: /usr/bin/m4: Bad _expression_ in eval: (1028* - /2)/100 stdin:5: /usr/bin/m4: Bad _expression_ in eval: (1029* - /2)/100 stdin:5: /usr/bin/m4: Bad _expression_ in eval: (1029* - /2)/100 stdin:5: /usr/bin/m4: Bad _expression_ in eval: (1030* - /2)/100 I renamed my symbol to xSO-23 and changed the test.sch file and all if happy in pcb land. George ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: SMD soldering challenge status
Dan McMahill wrote: I think we should pester Dave to fire up his SEM for some super close up photos! You know...My fiance' and I are hunting for a new house...one of the biggest requirements is enough space for not only my big iron, but for the SEM. It hasn't even had its vacuum system pumped down in something like five years. Actually just some decent optics with a camera mount would be fun. Hmm that would indeed be fun. -Dave -- Dave McGuire Cape Coral, FL ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: SMD soldering challenge status
DJ Delorie wrote: I think there ought to be a functional test... so how about a simple surface mount amplifier and input/output jacks. Again, if you can come up with a working circuit that (1) uses all the different footprints, (2) costs less than $2, and (3) fits in about half a square inch, I'm all for it. Mostly it's 1 and 2 I'm concerned about, 3 really just affects 2. Otherwise, you could buy any electronic kit. Now, a 555 and an amp, some caps and resistors, maybe we have something. Even just a little 555-based LED blinker or something would count as "functional" in this case, I think. -Dave -- Dave McGuire Cape Coral, FL ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
Re: gEDA-user: SMD soldering challenge status
DJ Delorie wrote: > Again, if you can come up with a working circuit that (1) uses all the > different footprints, (2) costs less than $2, and (3) fits in about > half a square inch, I'm all for it. My former employer did a little pcb as a christmas gift for well known customers. It is dual use: 1) Replace the coin you have to deposit in shopping trolleys. 2) A reasonably fast amplified photo sensor. The combined cost of OP27 plus BP34 is way above your budget though ;-) http://tem-messtechnik.de/OneEuroSchaltplanBestueckungsplan.htm (german only, sorry) ---<(kaimartin)>--- -- Kai-Martin Knaak [EMAIL PROTECTED] http://lilalaser.de/blog ___ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
