Eagle and "off board" components

[notneb]

   Using Eagle for the first time. Got my schematic done and ran into a little snag when I switched to the board layout. The switch and pots that I plan to mount off board and connect with a 5 pin Molex plug look fine in the schematic view but get in the way in the layout view,  and of course they can't be part of the routing because they're off board. Is it easier to just label the contacts on the Molex to correspond to the off board parts and leave them out, or is there a way to include them that I'm missing?

[R.G.]

Put them on a separate layer you can make invisible.

[notneb]

  Aha! Hadn't got into layers yet. Sounds crazy enough to work! Great... more to learn. But hey, thanks for the tip. Sounds like a plan.

[karbomusic]

You can also change the package to pads instead of the entire pot if you have a package that matches what you need.

[R.G.]

I tend to do the mechanical drawings first, then the PCB layout. It saves me a lot of pain and anguish.

One approach is to do the mechanical drawings for the pots and such in the box, then decide from that how to put places on the PCB for the controls to connect. If they're wires, just put pads.
[N.B.: really good layout uses the PCB to make the pads be in the position that makes the external wiring be easy.  ]

If the parts are PCB mounted, that's a different story. It is then CRITICAL to lay out the mechanical positions first, place the pads for the control leads on the board, then route the PCB around the control pads, which can't be changed.

I also use a separate design package for the mechanical versus PCB work. I used to do all 2-d drawings, but I'm using FreeCAD these days to do the entire box and all the parts including all the parts on the PCB and controls as a 3D model. It helps with visualizing.

As a side note, the very first component I ever drew up inside a PCB design program was a wire pad. It is a component - not just the random pads one puts on a board - and as such it's in the schematic and is part of the nets that the program maintains and checks for in testing the net completion.

[karbomusic]

I tend to do the mechanical drawings first, then the PCB layout. It saves me a lot of pain and anguish.

I'd swear I just read that a few days ago in this book "some guy" wrote.   

[R.G.]

Shhhh... it's viral advertising. And the first taste is always free.

[pappasmurfsharem]

They are offboard, but you still need the pads for the molex male headers and those still need to be routed.

If you just move the pots to an invisable layer, you wont have pads to install the molex headers.

What you should do then is instead is create three pads for each lug of the pot on the schematic. then label them P1,P2,P3 for the specified lug on the pot. Then place them in proper spacing do accept your molex header pins (I assume 0.1")

If there are multiple pots I would just label them with the first character in the pot function.

Gain would be G3,G2,G1 lugs
Volume would be V3,V2,V1 respectively.


Something like this.






Alternatively you can do as RG says and move them to an invisible layer, but you will still need to create the pads separately, and also make sure you name them the same as the pads for the POT.


If you aren't creating your own separate PAD part (however it will help you in the long run, so you really should)

You can just use the VIA tool to create the pad and hole size you want. Then label them with the text tool. Then use the name tool to change their name to the corresponding pad on the schematic.

So for instance in my example I clicked the name tool on one of the 3 vias I create. Then named it P3. Then eagle knows that a connection should be made from the C2/R2 junction to P3 (signified by the yellow line between them) otherwise you'll just have a useless pad that connects to nothing.

[notneb]

ok, physically, what I want to happen is this: Posts on pots/switches wired point to point as applicable, then the wires that NEED to go to the board (5 of them) go to the Molex connector, the 90 degree lug of which is mounted on the board. I want to be able to just unplug the pcb and remove it if I need to work on it. So I guess using the invisible layer idea doesn't get 'em routed and will show up as errors when I do the check. I guess what I'm getting, can I have the pots, switches... everything in the schematic and just leave them off the board area when I switch to the pcb view and rout them? The connections still show even before they're moved (but you knew that)... so if I leave them in the black area outside the pcb, will it still ... crap. Maybe I should just try it and see.