question to the designers.

[matrigs]

well - i wanted to ask you a question:

you see i had a big problem with my last project.

for maximum comfort, i counted  3 cm between every row of knobs.

now with the knobs, i didn't have any problems. but the buttons made me think. they are stuffed from the bottom on vector plates like this:

now when i tried to stuff them through the holes in the frontplate i realised that something is very wrong and that it won't match no matter what.

i measured again and and realised that this problem was because of the conversion of mills to mm on the board, and that there is no way of stuffing the buttons in the holes so that there will be exactly 3 cm between them.

so now i have to make a decision - either i'll make my own custom pcb projects for those buttons OR i'll change the project of the frontplate so that it will be in mills and not mm.

the thing i'm asking you, the builders is how do you do your stuff - do you make a frontplate and then project the pcb's or the other way round??

(on most of the projects i have seen in the gallery there are parts stuffed on "normal" pcb's so i guess you project the frontplate in mills then?)

((or maybe there are some special pcb's in mm? but then i guess the parts wouldn't fit...))

thanks in advance

[MTE]

Hi

oh I know this kind of problem when I was in the starting holes for layouting :)

For mounting breadboard-PCBs on the plate I made a breadboard-template (Holes 1mm Diameter, 2,54mm between the hole-middlepoints  !) in my layout, so I can see how the holes fit onto it.

Then I print the part of the layout with the breadboard to compare it with the stuffed, not soldered PCB

Maybe this picture can explain what i want to say, sorry for my english :)

Regards

[Jidis]

Hi Matrigs,

I've found it helps if you can export the exact image of the board/component layout into the app you do your panel layout in, just for temporary reference. I've taken board layouts from Eagle, with only the "Place" layers visible, and exported a bitmap image or something before. I can pull this file into my CAD app (Canvas), zoom in, and land circles, squares and rectangles directly over the individual part outlines from the layout. That way, I know they land where they go, even if the layout used a funky spacing. After I get all the hole areas outlined with the shapes I need, I usually lock them in place and delete the reference bitmap from underneath. If you're doing breadboard, you can still probably make a "dummy layout" using similar parts with the grid set to the desired spacing, and export those, or just draw out a grid in the CAD app (you've probably already done something like that).

<edit> And obviously, run a paper print out after you get the layout done, then go around it with a measurement caliper or a good ruler to make sure nothing needs to be "nudged". :o

(I guess the EXACT same thing MTE just recommended ;D)

Good Luck,

George

PS- I'll admit, I still end up with an occasional hole that's off by a hair from the drilling or something. If it's not that bad, sometimes you can save the soldering til last, and maybe elongate your PCB holes enough to wiggle the off part to where you need it, while it's mounted behind the panel, then lock it in place with the solder. 

[Sasha]

As English is not my native language, I dont understand quite what mills are, so I opened Corel to search the units and when I couldn`t find it I figured out you think of stripboard holes/pins spacing. Well you cannot convert it. The spacing on stripboard is standard 2.54mm or 0.1 inch. Will you give priority to panel layout or stripboard spacing is up to you. Both is OK. I always give priority to panel layout, as the 2.54 spacing don`t let to align some elements properly. Especially for projects like MBSEQ where I want to have encoder right belove the corresponding section of LCD. Maybe I am sick perfectionist, but having encoder out of the right section of LCD totally unacceptable for me, but most of the people wouldn`t mind and they would mount how stripboard force you, and that is in 2.54mm steps. I don`t actually use any PCB design software so I draw my buttons/LEDs... PCB`s using Corel Draw. Any vector program will do the job. Before I begin any designing, I draw footprints of all components I am going to use. After I am satisfied with panel layout, I delete everything except parts that needs to be on PCB, and draw connections to the place where connector should be placed. Of course, you can make just pads around the button/LED pins and solder wires directly to it. It is most simple solution without compromising panel layout.

Another way that I rarely practice is to make snapping grid with spacing 2.54 in Corel Draw and move the elements so their pins are snapped to the grid. In this case front-panel designing needs to be done after you finish button placement.

When you already made that nice panel, I advice you to put some more effort and make custom PCBs.

As you can see on the picture on attachment, PCB for my sequencer is very simple, but it is aligned to the LCD perfectly (as it should be)  ;)

PS. in the time I have finished this post you already had two replies, so I hope I`m not repeating much.

[matrigs]

thanks for those few replies!

i was just thinking about one thing:

the company that makes those plexy-frontplates for me claims they are using lasers that have an accuracy of 0,2 mm - that's not very good. on the other hand machines for making pcb's are much more accurate than that.

i'm just a bit afraid that the laser of the frontplate company won't handle measures like 2,54 mm exactly.

[Sasha]

i'm just a bit afraid that the laser of the frontplate company won't handle measures like 2,54 mm exactly.

You can always place butons and PCB on acrylic panel and when they are in place, solder it to the PCB. All cutting errors will be compensated as you can move the button that 0.2mm around so it sits nicely into right position. This is also only proper way of soldering LEDs To the right distance and X/Y position.

[Jidis]

This is also only proper way of soldering LEDs To the right distance and X/Y position.

Yeah, I did a board a few months back with a buttload of 3mm's on it. >:( After I saw how far off they were looking, I went back and etched this thing to hold them while I soldered. I had to desolder a couple rows and start over with the guide.

BTW- It started off as a row of 3mm circles with a center hole the size of a small drill bit. After etching, the center hole acts as a drill guide to get the holes in the right spot, then I enlarged them with a 3mm bit. My big problem before was in keeping the heights even. The lights are a nice snug fit in the guide holes, so you can line them up and they stay there while you solder.