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Low-profile PCB design
#31
I've made a list of all components we need (i believe):

SMD:
1x 1/4 10K
5x 1/4 1.0K
1x 470nF
1x IC-Socket 8pin
1x HC14
1x BC 847A

THT:
1x Female Header 2x13 pin
3x Female Header 1x4 pin
1x Terminal 1x3 pin
1x SMA Antenna
1x TSOP 4838

Did i forget anything?
 
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#32
(01-06-2015, 07:03 PM)curlymo Wrote: I've made a list of all components we need (i believe):

--cut--

Did i forget anything?

I've previously replaced the SMA antenna in the design with two wire antennae, I'm not sure how to connect the SMA and whether the sender and receiver would interfere or damage each other. Also, I've changed the capacitor value to 100uF and the 10k resistor to 1k, from my simulations this would work almost as well as the 470uF capacitor without being quite so huge. In SMD you could also get a Schmitt trigger inverter in dual packages (2 triggers) instead of the SN74HC14 which is a hex package (6 triggers). As we're only using one, I'd suggest using this one, which is much, much smaller. I've compared this list to the BOM in EAGLE and I don't think we've missed anything.

SMD:
6x 1/4 1.0K
1x 100uF
1x IC-Socket 8pin
1x SN74LVC1G14DRLR
1x BC 847A

THT:
1x Female Header 2x13 pin
3x Female Header 1x4 pin
1x Terminal 1x3 pin
2x Wire antenna
1x TSOP 4838

Today I got my first prototypes in the mail. However, I don't have the parts and my soldering iron here, so I'm planning on soldering it tomorrow. I have attached a picture showing how lovely they look. After I've done some basic tests (assuring that it doesn't blow up my pi, for example), I'll report back. As I'm not currently using a smart meter with my pi I can't really test that connection, but I'll test if the sender and receiver are working and I may look in to the IR receiver if I have the time. Even if we redesign the board on SMD this is still relevant, because it confirms that the schematic and board size and layout are correct.

   
 
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#33
I would still opt for SMA support with a single antenna. It should work because pilight never send and receives at the same time. So, there should be no interference between the two. We can even think of a small digital switch that get's activated when pilight starts sending. The sender pin is always look when idle so it shouldn't be hard to detect. So the antenna is disconnected from the receiver and connected to the sender when sending.

BTW, the boards look really good!
 
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#34
(01-09-2015, 01:12 PM)curlymo Wrote: I would still opt for SMA support with a single antenna. It should work because pilight never send and receives at the same time. So, there should be no interference between the two. We can even think of a small digital switch that get's activated when pilight starts sending. The sender pin is always look when idle so it shouldn't be hard to detect. So the antenna is disconnected from the receiver and connected to the sender when sending.

BTW, the boards look really good!

A separate, well-designed antenna would definitely be nice. Perhaps you could test whether a switch is needed by connecting the sender and receiver to the same wire antenna on a breadboard before we start complicating the design. If you do, make sure to power the sender on 3V as it is on the board. If this works without damaging either, it should work on the board as well. I do think we should also include a hole for a wire antenna as well as the SMA connector, as you can fit a wire antenna into an enclosure more easily (without having to cut a hole).
 
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#35
I think having a digital switch would be most fool proof. I'm don't have the expertise to know what happens when they are connected always.
 
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#36
May I do a suggestion for the 2x13pin header.

If you use a stackable header, then it will be possible to use the unused GPIO's with the PCB mounted on the Pi:

[Image: 1112-00.jpg]
https://www.adafruit.com/product/1112
 
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#37
Depends on how cheap we can get it from the suppliers. They are pretty expensive @adafruit. E.g. this one is 3x as cheap: http://www.reichelt.de/Female-Connectors...+094-2-026
 
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#38
I mean a stackable header and it doesn't have to be from adafruit.

[Image: 1112-00.jpg]

The stackable version has longer pins, so if you put that on the PCB, it is like you extend the existing headers. Like in this example:

[Image: stackheader.jpg]
 
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#39
I understood Smile
 
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#40
Hi Maarten,

I am very interested in your PCB and parts (including the addons CurlyMo suggested). Soldering (including SMB) is not a real problem. are you willing to sell one of your prototype boards?
 
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