How do you design these days?

Soldering with an oven is a black art. What sometimes works is to send a bare PCB throught the machine at the beginning of a batch. This helps to level the temperatures. It should be possible to solder any board, but it takes a lot of finetuning.

--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
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PC

Yup. It is very hard to model backing materials, acoustic matching layers, crosstalk and all that. This either needs to be characterized via some other software or measured.

One attempt in doing it mathematically ended with a first generation Pentium processor going tchk ... *PHUT*.

[...]

--
Regards, Joerg

http://www.analogconsultants.com/

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Roll yourself a Van Nelle Halfzwaar, light up, and all the smell is muffled :-)

What's that ugly big silvery thing on the right?

Looks like the cat peed over the speaker :-)

Main thing is, it works.

--
Regards, Joerg

http://www.analogconsultants.com/

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burn.

Very useful. The remaining flat cable makes a good handle. See the other wires in the above link.

Happy new year, Falk consult42.com/tmp/fireworks2010-0.5MB.mpg consult42.com/tmp/fireworks2010-11MB.mpg

...

Half... Pah!

...

Looks like McGuyver^WDuck-Tape

Falk

Oh, a real connoisseur :-)

Gauloises self-rolled is pretty good. But that was a long time ago.

The top, yes, but there is some serious oozing underneath.

--
Regards, Joerg

http://www.analogconsultants.com/

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On a sunny day (Thu, 31 Dec 2009 16:22:20 -0800) it happened Joerg wrote in :

It is 'bison kit', or translated 'Bison Glue'. Lots of it to keep that speaker fixed, had to re-glue it a couple of times. Maybe Bison Kit is made of Bison pee, I really do not know what is in it, but it is a very good glue for general purpose application.

On a sunny day (Thu, 31 Dec 2009 16:35:47 -0800) it happened Joerg wrote in :

The idea a an acoustic short, As the speaker front side is against the PCB, and the PCB has holes, the holes most be closed to prevent an acoustic short. the speaher radiates from it's back, which is on top. I guess I could have soldered the holes closed.

On a sunny day (Fri, 01 Jan 2010 01:29:35 +0100) it happened Falk Willberg wrote in :

burn.

The same. Nice. I had 2 cameras running for the fireworks,

1 320x240 @60 fps, and 1 640x480 @50fps About 90 minutes material altogether, need to look at it and edit out the useful parts.

It's too long ago but AFAIR we used something like Araldit in the Netherlands back in my days. The spelling could be wrong but it held on very well. It didn't leave such nasty residue unless you let it ooze all over the place. Ok, it wasn't exactly the Netherlands but the province of Zuid Limburg which you guys considered a foreign country.

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Regards, Joerg

http://www.analogconsultants.com/

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theftp://panteltje.com/pub/z80/graphics_card_top.jpg second OLED

ACK! We were going out for beer and burgers, but you just killed my appetite.

This is more like it. The bottom board is my one-off signal conditioner/relay driver. And I built a spare.

ftp://jjlarkin.lmi.net/Auto_plate.jpg

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Audio: It is doubly troublesome when you are designing for things that need to work over a range of pressures. The mechanical characteristics of materials change with stress. Resonant frequencies tend to move about and some things make noise for unexpected reasons.

Electromagnetic: The electrical properties of soil are all over the map. Check out Bruce Candy's patent on how to reject magnetic soils in a metal detector some time. It actually works (mostly kind of)

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Vector board is insanely priced. I buy it up at flea markets when I find good deals and nibble out small pieces for circuits to conserve it. I think if I had to pay real prices for vectorboard, I'd use the on-line PCB manufacturers. I dead bug too.

Funny nobody mentioned using a board grinder.

Live bug is easier to visualize. And if you work on copperclad, you can bend ungrounded pins out horizontally and solder the groudable pins directly to the plane.

Kapton tape is great, too, when working on copperclad.

John

Keep firing people who have that attitude and it eventually will be!

Best regards, Spehro Pefhany

--
"it's the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

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The backwards pinout is an issue. I sharpie the pin numbers after I mount the dead bug.

For those interested in dead-bug prototyping, see my video blog:

Dave.

--
---------------------------------------------
Check out my Electronics Engineering Video Blog & Podcast:
http://www.eevblog.com

On a sunny day (Thu, 31 Dec 2009 17:22:14 -0800) it happened Joerg wrote in :

Araldit is a 2 component glue. It sets faster when heated too. Bison kit is a one component, apply to both sides, wait 3 minutes, push together glue from a tube. Bison kit stays a bit soft or flexible, while Araldit becomes stone hard.

On a sunny day (Thu, 31 Dec 2009 18:13:00 -0800) it happened John Larkin wrote in :

It looks very nice, but those screw terminals... I have had some molten ones, probably because I used those at 10 A. Am I imagining it, or are there awfully small traces going to those terminals?

*Fusible* traces? ;-) Would not a few real connectors be easier? My LM135 temp sensors ends in a stereo phono plug, as do all other sensors.. ground, +5 fed via a resistor, and signal. The same way I drive LEDs. So I just plug the sensors in like a headphone, and can easily swap each.

The digital inputs / output are driven by a PCF8574 (bidirectional i2c I/O expander), and the inputs by a PCF8591, a 4 channel i2c 8 bit AD + DA converter. The i2c hands on 3 pins of the PC par port. In the original design there was a local LCD driven by 2 PCF8574 remotely too. No RS232 then. This has been working since the eighties without problems, but I accidently killed the LCD (main wire dropped on a data line), and took it out. The original soft was also in BASIC, MCS BASIC on a 8052 ! Anybody remember MCS BASIC? Then rewrote it in C, and ported to CP/M. That C ported to DR DOS. That DOS C ported to Linux. And it still works today:-) Recently I added a temp PIC temp sensor via an USB to RS232 adaptor,

if that sensor fails (is not connected) the software detects it, and switches back to the LM135. Interesting to write the soft that detects all the possible USB errors, finally had to have it check the data format the temp_pic sends, to make sure USB enumeration had not caused some other sensor to be read.... i2c was and is, a lot simpler, not sensitive to random delays due to multi-tasking OS either. temp_pic sensor is cool, had it in the fridge to -18, and in boiling water to

100 C.