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Low-profile PCB design
#21
(12-19-2014, 06:37 PM)curlymo Wrote: In regard to your points:
1. Ok.
2. The whole point of of course using a RJ11 socket is the ease of it.
3. Don't.
4. Smile
5. Does mijnprintplaat.nl also pre-solder the common parts? That would be sort of an requirement.

Looking at your circuit:
1. The IC2A 2 output should go to the RxD. It doesn't seem like it does. The RxD is at the same side as the 5v.
2. Is there a reason to use different default sender / receiver pins?

Some other questions:
1. Can the IC1 actually become a 8pin IC socket?
2. Are the sender / receiver connected headers?
2. I know, but my goal was to make a PCB that fits inside a case. As you can see the PCB is already pretty full. I think connecting the wires to a screw terminal is a good compromise.

1. I see the connection is reversed. I'll change that.
2. I wanted to use primarily pins on the side of the board away from the edge, due to easier accessibility

1. The pins on a socket are in the same place, so it should simply fit.
2. The board was designed to be as easy to solder as possible, by using a through-hole packages. I haven't looked into a supplier that assembles the board as well.
 
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#22
2. And placing the RJ11 socket between the circuit board and the Raspberry Pi instead of on top?

1. ...
2. ...

1. ...
2. I would rather not solder the receiver and sender, because they're massively sensitive. I also want to give users the option to swap sender and receiver themselves. Just like the ATTiny.

3. Can we also add a header on top so all covered pins can stil be used?
4. Are there suppliers that offer presoldered solutions (for common parts)?
 
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#23
(12-19-2014, 07:19 PM)curlymo Wrote: 2. And placing the RJ11 socket between the circuit board and the Raspberry Pi instead of on top?
-No, the space between the board and the RPi is less than 10 mm, I couldn't find any connector that would fit in that space. Most connectors I could find were pretty bulky...

(12-19-2014, 07:19 PM)curlymo Wrote: 1. ...
2. ...

1. ...
2. I would rather not solder the receiver and sender, because they're massively sensitive. I also want to give users the option to swap sender and receiver themselves. Just like the ATTiny.
-Yes, this was always my intention. On the board you'd solder straight-angled female headers (like these), in which you'd simply push the sender and receiver.

(12-19-2014, 07:19 PM)curlymo Wrote: 3. Can we also add a header on top so all covered pins can stil be used?
-That can be done by using a stacking board connector instead of a simple header on the bottom, I'm using these, 'cause they're cheap, but someone who'd want access to the remaining headers could use something like this, which has long leads so they are accessible from the top of the board (although that specific one has pretty large leads, I don't know if that'll fit, I'll look into that, UPDATE: found this one, which will probably fit quite well).

(12-19-2014, 07:19 PM)curlymo Wrote: 4. Are there suppliers that offer presoldered solutions (for common parts)?
- Yes there are some assembly services, but they tend to be quite expensive. Just google 'pcb assembly service', some examples in The Netherlands are Holtec Electronics, EuroPCB and EPR Technopower, but I don't know if they want to do small series and what the costs would be (I'm expecting quite a lot).

(12-19-2014, 06:37 PM)curlymo Wrote: 1. The IC2A 2 output should go to the RxD. It doesn't seem like it does. The RxD is at the same side as the 5v.

I checked again, but it seems my design is the same as the one you posted. I read it as the part labeled M041 being the RJ11 connector and the RxD net being connected to a GPIO header on the RPi. This is as it's connected now, is this incorrect?
 
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#24
Yes, IC2A 2 should go to pin 10. See here: https://projects.drogon.net/raspberry-pi/wiringpi/pins/
 
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#25
(12-20-2014, 12:12 AM)curlymo Wrote: Yes, IC2A 2 should go to pin 10. See here: https://projects.drogon.net/raspberry-pi/wiringpi/pins/

Ah right, I thought just any header would do. Fixed that now
 
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#26
Can you maybe check what it would cost @http://www.seeedstudio.com/service/index.php?r=pcb
Another one i found in the Netherlands is this: http://www.proto-service.nl/prijs-indicator#result
 
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#27
(01-01-2015, 02:13 PM)curlymo Wrote: Can you maybe check what it would cost @http://www.seeedstudio.com/service/index.php?r=pcb
Another one i found in the Netherlands is this: http://www.proto-service.nl/prijs-indicator#result

I've already ordered some prototypes here. This cost me $20,49 for 10 pcs (less than €1,70 per piece). These are of course not assembled and components are not included. I'm expecting the boards to be delivered somewhere in the coming few weeks.

I've checked proto-service, but this service is mostly targeted at SMD boards, which are more suitable for automated assembly. The board I've designed uses through-hole components (because these are easier to solder by hand).
If the board is redesigned using SMD components, my best estimate is that it'd cost between €10 and €15 when ordering 10 pcs or between €3 and €6 when ordering 100 pcs. This is per piece, excluding the cost of the components and VAT.
 
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#28
SMD components would be best. I just don't have time to start soldering everything and our users are generally not technical engineers Wink (neither am i). SMD would also be best for space considerations.

Did you also notice that proto-service also does THT?
 
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#29
(01-01-2015, 06:44 PM)curlymo Wrote: SMD components would be best. I just don't have time to start soldering everything and our users are generally not technical engineers Wink (neither am i). SMD would also be best for space considerations.

Did you also notice that proto-service also does THT?

I saw that, but the price indicator requires you to fill in a number of SMD components, even if you're not using any, so I'm unsure whether these prices are true even if you're using only THT. Usually soldering THT is more labour intensive than SMD. Perhaps we could contact them to get a better indication.

Of course, if we would use SMD it would be easier to implement new functionality (because it's much more space efficient). However, if we do decide to go SMD, any notion of letting the user solder it by himself goes out the window, because not everyone knows how to do that (I don't, for example). I actually quite like the idea that anyone could simply modify the EAGLE files for their own purposes, order a single PCB and then solder it by himself.

By the way: don't fret the soldering too much. The components we're using are very sturdy (especially when not soldering the ICs directly but using a socket) and the board has a nice solder mask, so the tin will flow where it needs to go and is unlikely to make any shorts. The amount of technique required is minimal.
 
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#30
Yes, please contact them or I will, but we first need to figure the exact components we want.

Also, don't get your hopes up that people will actually modify stuff that quickly. 99.9% of the users are consumers. Nothing wrong with it. The last 0.1% are contributers. If users want to modify the EAGLE files they still can: from SMD -> THT.

Selling circuits boards only works when we can have pre-assembled ones. Any other option will be too labor intensive or too technical for most users.
 
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