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ElectronicDesign (2006-09-26 13:35:16)

developer notes on tools we use or thinking about

Eagle project management:

We have found that each eagle project needs it's own library files, otherwise we get problems now and then as the library files are updated. As an example it's hard to remember that a certain pad was shrunk on a specific design a year later when you need a slightly bigger pad on an other design. The problem would not come at once but maybe when you update the library because of some other change to the first project!

In the project file (epf) eagle stores which libraries are used for a specific project. Those libraries are the ones that show up in the 'Add component' dialog. It is important that these libraries are copies of the main library files in the Eagle program directory.

The copies are made from the eagle sch and board files with the use of a script. Kieth usually handles this now and then, only he has understood how Eagle has to be used in a multi project enviroment before.

Eagle_project2.png

Eagle_project3.png

Remember to close the project when you stop working with it.

As the 'Add component' Dialog only has the components already used when we work this way we have to add all new components form the Eagle control panel:

Eagle_project4.png

If there are more then one possible footprint this dialog will then be popped up for you to choose from.

Eagle_project3.png

It's a bit backwards to do it this way but it has to be done this way to avoid problems in the future.

Recommended sizes

Note that normal PCB send-in daily deadline for our main PCB manufacturer changed to 08:30 CEST (from earlier 10h).

We have an alternative PCB manufacturer, http://www.satronik.hu that makes PCB in 1 week (but max 2 layers, min via drill=16mil and last time they only liked traditional gerber format vs. gerber_rs274x), but we like the better solderprotect strength of the main manufacturer. On the other hand, starting-batch costs of this manufacturer is incredibly small. Therefore, if you want to manufacture with small total PCB area, because of small size like 150 pieces * 30mm x 40mm or because of small series, and no other design (of same layer-count) to merge with (they merge the gerbers), it's a good choice. MembersPage/MarcellGal can help you with

Recommended parts

During sch + layout design there are often compromises. Sometimes designer hesitates to add some board optimization that would increase BOM linecount, such as using both BAV99 and BAW56 instead of just BAV99. BOM linecount and partcount has related manufacturing costs, naturally, but usually fairly small. In general I recommend to make optimizations, a few added BOM items are no problem.

Some notes: think about parts below and use them with cheers:

Spice and clones (eg. acs) for simulation

PCB SW:

Eagle schematic and PCB editor (and it's license terms!) from http://www.cadsoft.de/

I use the Eagle 4.11 professional license, but eagle with any license can view sch or pcb, and any can edit the one-page (therefore a bit clumsy looking) schematic. Eagle is a relatively shitty program. The lack of some very simple functions make your life hard.

Eagle wishlist:

eagle working list:

GEDA GNU electronic design automation.

These software are good for simple design. VEMS team mostly uses Eagle. Autorouter functionality is poor, but 2 layer boards must be routed manually for sane result anyway :-)

[eagle help]

do you know how to share info between PADs and Eagle schematics and layouts? Have links? A friend insists on PADs (which he paid serious money for) and would make smaller boards (eg. stepper-driver for a special app, special form-factor).

HW:

PC-scopes

Sly, you recently collected info about PC-scope, where can your research be found ?

Signal generators - PC soundcard is enough for most of our tasks

Virtual trigger signal generator by Ray Hall, handles the most common stock trigger arrangements:

http://www.autronic.com/software/SignalGen.zip

Interesting links, practices, examples:

ManuFacturing links, eg.: ManuFacturingInHungary

See also MechanicalDesign, BuildProcedures

4.11 Eagle Lite Sources

[German]

[English]

AVR simulation (should have it's own page?)

See also