How to make PCB symmetrical in EasyEDA?

[neiltheseal]

Hi everyone

I have been messing around with EasyEDA and I *think* I have my head around it.

However I wanted to know if anybody had any tips on how to make PCBs symmetrical. So far I have been lining things up by sight measured against a grid size that seems to make sense to me. Is there a better way than this?

Also, is there a way that I can convert this to make my own drill template for an enclosure? I really hate measuring enclosures by hand and would love to use a drill template.

Thanks in advance.

 

[damianvila]

The best way I found to deal with this is by measuring from the center. I’ll explain:

Say you want to design an enclosure. You want to put the pots symmetrical. You want this to correspond with the PCB.

Let’s say you have 3 pots, two on the top row, and one centered on the bottom row. The top pots are separated by, let’s say, 40mm, and the top row is separated from the bottom row by 20mm (all hypothetical).

Now, let’s say the PCB width is 60mm, and the enclosure width is 80mm.

The design part is easy. Top-left corner is 0,0. Let’s say the pots are 20mm from the top. First pot is 20,20, second pot is 60,20, and third pot is 40,40.

Now, you go to EasyEDA, and the coordinates are cartesian (0,0 is at bottom-left). So, let’s say the pcb heights is not a problem, and it’s 40mm (width, as said previously is 60mm). And you want to put the pots in a position corresponding to the design, and centered on the pcb.

So, you take the center of the pcb, at 30,20. First pot will be half the distance of the other pot to the left (-20, since the pots are separated by 40mm), and half the distance from the second row to the top (+10, since rows are separated by 20mm, and going up is positive). So it’ll be at 10,30 (30-20, 20+10). The second pot is +40 to the right of the first, so 50,30. And the third is centered, but 10 to the bottom (-10). So it’ll be at 30,10.

And that will be positioned exactly like in the design, with the pcb centered (you just need to pay attention to dimensions and the pcb not touching any side of the enclosure, so if needed, move everything up or down as needed).

You can use this center point (in our example 30,20) as a reference to place the rest of the components.

I hope I made myself clear. If not, I’ll try to explain it better tomorrow.

 

[neiltheseal]

The best way I found to deal with this is by measuring from the center. I’ll explain:

Say you want to design an enclosure. You want to put the pots symmetrical. You want this to correspond with the PCB.

Let’s say you have 3 pots, two on the top row, and one centered on the bottom row. The top pots are separated by, let’s say, 40mm, and the top row is separated from the bottom row by 20mm (all hypothetical).

Now, let’s say the PCB width is 60mm, and the enclosure width is 80mm.

The design part is easy. Top-left corner is 0,0. Let’s say the pots are 20mm from the top. First pot is 20,20, second pot is 60,20, and third pot is 40,40.

Now, you go to EasyEDA, and the coordinates are cartesian (0,0 is at bottom-left). So, let’s say the pcb heights is not a problem, and it’s 40mm (width, as said previously is 60mm). And you want to put the pots in a position corresponding to the design, and centered on the pcb.

So, you take the center of the pcb, at 30,20. First pot will be half the distance of the other pot to the left (-20, since the pots are separated by 40mm), and half the distance from the second row to the top (+10, since rows are separated by 20mm, and going up is positive). So it’ll be at 10,30 (30-20, 20+10). The second pot is +40 to the right of the first, so 50,30. And the third is centered, but 10 to the bottom (-10). So it’ll be at 30,10.

And that will be positioned exactly like in the design, with the pcb centered (you just need to pay attention to dimensions and the pcb not touching any side of the enclosure, so if needed, move everything up or down as needed).

You can use this center point (in our example 30,20) as a reference to place the rest of the components.

I hope I made myself clear. If not, I’ll try to explain it better tomorrow.

Thanks, this is really helpful. I think I have my head around it. I managed to build a nice symmetrical PCB in EasyEDA.

Is there a free layout tool that you could recommend for me to make a print template? I don't have photoshop and It would be a pain to have to do this with a ruler on paper.

Thanks again.

 

[szukalski]

Just bear in mind, whilst symmetry is pleasing, you should ultimately aim for a well laid out pedal with short audio traces.

 

[neiltheseal]

Just bear in mind, whilst symmetry is pleasing, you should ultimately aim for a well laid out pedal with short audio traces.

Thanks. I meant more that the pots/led are symmetrical. I’m trying to make my life easier when drilling holes.

I actually have no idea what I am doing layout wise so have been copying layouts online. I may have copied some of Robert’s layouts. But these are for me and I won’t be selling them. Just a learning exercise .

 

[szukalski]

LEDs can go where ever you want, but it generally makes sense to either put them at the top of bottom of the board because you will have a trace that goes from the LED to the SW out at the bottom of the board and you need to think about how to route that. Right down the middle of the board seems the easiest, but this can dominate your layout and make other traces inefficient. Tracing it around the edge of the board is a good approach.

For pots, then I like to align with the PPCB standard for pot/switch spacing. It's a good one, works with existing templates, and is a nice standard in general. I base all my boards around 0,0 as a starting point where I put my top IO and top row of pots.

• 2-knob width
  • 0.65" spacing = 16.5mm
  • This is the spacing from the middle point, so the two knobs will actually be 33mm apart. One knob is +16.5mm from the center, the other is -16.5mm
• 3-knob width
  • 0.8" spacing = 20.3mm
  • In this case, the 3 knobs at the top would be -20.3mm, 0mm, +20.3mm on the X axis (0 on the Y).
• Space between rows
  • 1" = 25.4mm
• Toggle switch
  • 0.63" above pots = 16mm above pots
  • This is where pot shaft lives

To put it all into perspective, a 4 knob with middle toggle, like the Acer Overdrive, would have (X,Y in mm):

• Top row knobs
  • (-16.5/0) (16.5/0)
• Toggle switch
  • (0,3.3)
• Bottom row knobs
  • (-16.5/-25.4) (16.5/-25.4)

 

[neiltheseal]

LEDs can go where ever you want, but it generally makes sense to either put them at the top of bottom of the board because you will have a trace that goes from the LED to the SW out at the bottom of the board and you need to think about how to route that. Right down the middle of the board seems the easiest, but this can dominate your layout and make other traces inefficient. Tracing it around the edge of the board is a good approach.

For pots, then I like to align with the PPCB standard for pot/switch spacing. It's a good one, works with existing templates, and is a nice standard in general. I base all my boards around 0,0 as a starting point where I put my top IO and top row of pots.

• 2-knob width
  • 0.65" spacing = 16.5mm
  • This is the spacing from the middle point, so the two knobs will actually be 33mm apart. One knob is +16.5mm from the center, the other is -16.5mm
• 3-knob width
  • 0.8" spacing = 20.3mm
  • In this case, the 3 knobs at the top would be -20.3mm, 0mm, +20.3mm on the X axis (0 on the Y).
• Space between rows
  • 1" = 25.4mm
• Toggle switch
  • 0.63" above pots = 16mm above pots
  • This is where pot shaft lives

To put it all into perspective, a 4 knob with middle toggle, like the Acer Overdrive, would have (X,Y in mm):

• Top row knobs
  • (-16.5/0) (16.5/0)
• Toggle switch
  • (0,-9.4)
• Bottom row knobs
  • (-16.5/-25.4) (16.5/-25.4)

Thanks.

That sounds like a good approach. So the top row of pots are 0 on the y axis? So I suppose when building a print template around that the pots would then be -16.5/20 and 16.5/20 for example?

This is assuming that the centre of the pot is 20mm from the top? Have I understood correctly?

And if I put the led at the bottom of a 60mm pcb it would be 0/-60 and on a print template 0/-80?

 

[KR Sound]

Post in thread 'Getting drill guides from Eagle PCB'
https://forum.pedalpcb.com/threads/getting-drill-guides-from-eagle-pcb.15025/post-173650

 

[Guardians of the analog]

Just bear in mind, whilst symmetry is pleasing, you should ultimately aim for a well laid out pedal with short audio traces.

That fits the enclosure