Hi All,

I'm observing an increasing number of posts concerned with Eagle problems. First of all the full word for the abbreviation EAGLE. It stands for what it really is, an Easily ApplicableGraphicLayoutEditor.

As any software, Eagle of course has some bugs (mainly the autorouter). Getting used to them working with Eagle is fun, even creating new devices.

If you need a sophisticated package don't hesitate to send me the data sheet or a link. I'll be happy to make it for you.

Today's trick: You intend to put some copy protection on your circuit board. A stamp can be easily removed, but how about a component? That's what we're going to do today.

Step 1: Create your logo either on the solder, component or top layer as a package. Use at least one pin for it. The accepted minimum pin diameter is 0.01mm and the drill size 0.001mm. We're going to use that as a connection to the logo. Select octagon as pad shape. Name it "1".

Step 2: Make a symbol just with one pin and nothing else. Use lenght "point". Name it also "1".

Step 3: Create the device using the symbol and advice package, e.g. "logo-s" (logo on the solder side). Connect the pin.

Step 4: Done - Save

Place the device somewhere within your schematic, best on another component pin. It will automatically connected to that net. (Don't forget where you put it!) Do that after the schematic and the board are finished to find a place adjacent to a trace without problems.

Switch to "board" and the logo is there, outside the dimension layer. Pull it to the place you want. Now you will have an air wire to the next trace with the same net name. Disable the "unrouted" (layer19) layer for a clean print. Try to erase the logo on the board. No way to do that! You must delete it in the schematic, and ONLY YOU know where to find it.

Have fun

Regard to All

Hans

 

I have never tried this, but couldn't one use the information tool, find what the logo or net is called, then use the "show" command in the schematic to highlight it?

John

Edit: Another workaround is to highlight, cut, then paste the board on a fresh screen. That breaks the link to the schematic and allows deletion of components. John

 

Hi,

I am just curious, did you switch to Eagle 5 or still using the old version (4.16). I am not sure if to go to 5.0 as I know I can't go back once I convert the data to 5.0

Petr

 

Hi John,

the first way won't work. How can you highlight a pin on another pin? Placing the pin of the logo on another lets them "melt" together, and highlighting wouldn't do anything. E.g. placing the pin on a GND symbol it will automatically display GND, which is correct.

The second way however is the only one to delete unwanted elements. But one must have the idea to do this. Not being able to delete an element which is not visible in the schematic will lead to the assumption that there is a real protection.

Hans

 

Hi petrv,

I can't see whom you asked. Anyway, I'm using both 3.55 and 4.16. I prefer using 3.55 because I have made hundreds of new devices (mainly electromechanical) using it and so I know where to find them.

Switching to version 5.x is as switching from any lower version to a higher one. The higher versions of Eagle are never downwards compatible.

To try version 5.x I suggest to make copies of your 4.16 version projects in a separate folder and see what changes are made in 5.x.

Hans

 

Hi Hans, I need to actually test your method. Initially, I keyed on the words "device" and "net". They would have names that could be found with the information tool. Of course, the user would need to know to show all.

I suspect the procedure to copy a board may be fairly well known. I use it is when I have a board that doesn't fill the entire space available on the PCB blank. I make multiple copies or add other boards to one "brd" file and then print that out for my photo positive.

As for protecting a board design, doesn't copyright cover that? One might consider inserting the copyright symbol.

John

 

Hi John,

respecting copy right is something for honest people. I've never seen a legal copy of windows xp here in Thailand. Even some semiconductor manufacturers have taken Thailand off the list for free samples. Bad for me since I'm German.

I purchased a rotary saw the other day and after two hours of operation the motor went up in flames. The device had the emblem of "Talon", a famous tool manufacturer in Australia. Very much to my surprise Talon never made rotary saws.

Anyway I will think about a more effective way to protect a circuit design. So far I've made a logo with two pins placed on two pins of the schematic - one at each end of the net. If the logo is removed the trace will be removed too - inivisible to the copier - not leaving an air wire, but a missing trace for an important function (e.g. RS pin of an LC-display) will screw up the entire board. Debugging will be impossible since the backward annotation was disabled by copying.

I'll work out a solution which is difficult to trick, if at all.

Hans

 

Good luck. From a philosophical standpoint, I think protection by design is eventually futile. Just look at the years of development that went into development of security for Windows. John

 

I agree. The OP should consider the fact that someone who wants to steal a design will not be concerned with Eagle tricks (they wont even use it!).. just go into the Gerber files and wipe out any logo or anything else they want. After all, gerbers must be generated for the PCB to be manufactured and that's where the design is most vulnerable. There is software to edit Gerbers directly... why bother with logo tricks!

Send me your design, I'll send it back to you without your logo and with some of my own stuff in it. :-)

 

This may be a little OT, but since the title was hint & tricks, maybe it is not too far off.

One thing I would like to see is a library of packages. There already are many packages available as part of devices that can be copied, but finding the right one can be difficult. I envision a collaborative project with one person (do I hear a volunteer, Hans?) collecting them for submission. I would certainly be willing to send some of my favorites to whomever wants to organize it.

John

 

There is a pretty comprehensive package library, called smd-ipc.lbr. More on smd-special.lbr.

 

"Never mind" (Gilda Radner, circa 1980, SNL) Simply had not bothered to look at those. Thanks. John

 

Hi Optikon,

you might be right, but I must direct you to one important point: the Eagle file goes before the Gerber file, which is created on the basis of information Eagle provides. If an information is missing the result will be a faulty PCB. Of course, knowing that just a "cheap" little logo messes up the design if missing must be known before "correcting" - otherwise a null function board.

Editing the Gerber file will only be successful if the sequence is correct: Copy the original file --> convert to Gerber --> make the necessary changes.

Some years ago I had to make an air data computer for a customer using lots of toluol, a highly explosive thinner for printing colours. The design was a unicate and my copy protection was two different versions of the schematic. Also combining several XOR gates for the function of a simple OR-gate makes it more difficult to grasp that stuff.

Hans


BTW: Nothing is impossible - TOYOTA

 

I am not an expert PCB layout person.
The following works for me.

Create board using the 8 mil defaults and have it pass ERC and *DRC.
Then change the following.

Restring-Pads Bottom to 15 mil
Restring-Pads Top to 10 mil **
Restring-Pads Vias Outer 15 (esp for DIY boards)

Fix the DRC errors.

Increase all 6 box values in "Clearance-Different Signal" by steps of 3 to 5 mil for several passes, run DRC between each pass. Greater spacing makes the board easier to solder. I shoot for between 15 and 20 mils. Some errors will be unfixable such as traces between pads and the distance between the edges of a solder jumper. When you encounter these errors approve them in the DRC Errors dialog.

When finished you will have a board that is easy to solder and modify because it has both large easy to solder pads and generous spacing.

Layout is very much an art. Each time I revisit a layout I find a few things that can be improved. At some point it is good enough but you can take it as far as you like.

Note:
* Turn off tstop and bstop layers when doing DRC.
** Does not matter for SS boards. For DS boards I use 10 mil restring because it makes it easier to run traces between pads. Generaly top pads are are only soldered if you use them instead of a via. In general only diodes and resistors can be soldered on the top layer. If you do this, note each top connection in the assembly section of your project description in Eagle.

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No problem. To be honest it took me 2 years to find them.