Eagle / OSH Park, how to get UNplated hole with pads

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1

I'm designing a board for an I2C device that provides 16 possible addresses with 2 address inputs by allowing them to be connected to Vcc, GND, SDA, or SCL. I'm trying to find an area-conserving way of making this user selectable at build time.

An idea is to use pads top and bottom and unplated through holes, so a Z-wire can be soldered in as a jumper.

Question 1: how can I get what is effectively a via or TH pad with an unplated hole from OSH Park (formerly Dorkbot)?

Question 2: is there a better way to do this? Use multiple board designs? Suck it up and waste some board real estate?

-j

2

Looks like I can probably do this with 4 holes (Vcc, gnd, sda, scl) large enough for 2 small wires, and two small holes (A0 and A1) large enough for a single wire.

-j

3

So you just want a hole? Same as a mounting hole you might put a screw thru, but a different diameter?

4

yeah, only I want it through two pads, one on top and one on bottom.

That's the way I thought about doing it - make some round SMT pads and put holes through 'em. I know the DRC will scream, but I think the fab process should be OK.

The more I think about it, though, the more I think using wires would be better/simpler than figuring out how to make some compact 2x4 jumper array.

-j

5

You should be able to had a hole, and then just draw a wire circle around the hole on both sides with 15mil trace width or similar. Give the two wire circles different names so the don't get connected, and make sure the inner diameter is larger than the hole.

6

Using "holes" in Eagle as mounting holes, they come back from iTead plated through. Not sure I've tried one with OSH Park though.

I might try giving them a shout.

7

What about a chunk of this and some of these?

8

Using "holes" in Eagle as mounting holes, they come back from iTead plated through.

Sounds like a broken fab process?

What about a chunk of this and some of these?

doesn't really work for a 2x4, without getting really big - like doubling (or more) the size of the PCB.

-j

9

I am looking at some quite recent boards and some older boards from itead, and the holes do look different.

Older ones do look plated inside the holes.
Newew ones do not.

I think my idea of putting a wire circle around a hole will work fine.

10

CrossRoads:
I am looking at some quite recent boards and some older boards from itead, and the holes do look different.

Older ones do look plated inside the holes.
Newew ones do not.

I think my idea of putting a wire circle around a hole will work fine.

Interesting. The batch I received a couple weeks ago are definitely plated through. 0.125" mounting holes at the corners of the boards. Certainly not a issue for my purposes though.

11

Having unplanted holes requires an extra drilling step in the fab process, which is uncommon in the low cost prototype deals.

12

My OSH Park boards have unplated drill holes.

-j

13

The latest arrivals from iTead have unplated mounting holes. I want to say all previous orders had plated mounting holes (at least those that had mounting holes). Curiouser and curiouser.

14

I just saw this, whats the reasoning behind having non plated holes, then soldering a wire, why not just have them plated if your connecting both sides of the same pad?

15

OP wanted to use them as jumpers to configure the circuit in various ways.

16

I'm trying to get a 2x4 jumper arrangement - two address lines, each jumpered to one of 4 other lines to select an address. The target PCB is quite small - about 1" x 0.75" - and I don't want to increase the board size by 50% just to get configuration jumpers.

I think I'll end up using wires as jumpers (which I was originally trying to avoid), so I can do it with a total of 6 plated through-holes. To save space I may see if I can do it with slightly oversized vias and 30ga wire.

-j