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update the hub board design to eliminate through-hole components #4

Open williamcodes opened 8 years ago

williamcodes commented 8 years ago

They're easy to solder in prototyping, but expensive to manufacture. Also, we have a manufacturing partner that wants to work with us with INSANE discounts but can't do through-hole components. If we can switch to SMD headers, then we can work with them. They said that thought it would probably only take an hour to update the eagle file.

williamcodes commented 8 years ago

Copied from Doyun's email

I have questions on this issue. So what I need to do is make two parts (xbee and raspberry pi gpio header part) surface mounted form.

  1. It seems like xbee part is made by Harold. I thought it's through-hole but the picture William sent to me has a header. They look different to me , so I want to know what component it is.
  2. We have two versions on Github, within and without. What's the difference and should I update both?
  3. I guess this hub part will be a hat to raspberry pi. This header is using M9X2 device and 2X9_NOSILK package from Harold's library. Is this also through-hole or similar to what I saw in above picture?
  4. I want to see the picture of previous hub!
williamcodes commented 8 years ago
  1. I'm not sure I follow actually. What is the question?
  2. Excellent question! I have no idea. @hrldcpr what's the difference between within and without? Looks like something to do with space saving? Confused.
  3. Yes, I love that, the hub part is the raspberry pi's hat. He's got great fashion sense! As for the pin headers, they are currently through-hole components. @hrldcpr can you confirm that? Perhaps the photo will clear things up.
  4. Photo shoot! Time to show of that swanky hat. 2015-12-21 23 28 41 2015-12-21 23 28 05 2015-12-21 23 27 38 2015-12-21 23 27 26 2015-12-21 23 26 50
hrldcpr commented 8 years ago
  1. Yeah the "XBee" part was really just a way to align things, in reality it is two headers, specifically this one - http://www.digikey.com/product-detail/en/NPPN101BFCN-RC/S5751-10-ND/804812
  2. within was an alternative design that we never used. I've gone ahead and deleted it from the repo to make things clearer.
  3. All three headers in the current design are through-hole. The header that connects to the π is this one - http://www.digikey.com/product-detail/en/PPPC092LFBN-RC/S7112-ND/810249
qelloman commented 8 years ago

Raspberry pi header replacement : small amount (minimum quantity 1) : http://www.digikey.com/product-detail/en/NPPC092KFMS-RC/S5718-ND/776177 large amount (minimum quantity 1000) : http://www.digikey.com/product-detail/en/NPTC092KFMS-RC/S5679-ND/776138

XBee header replacement : http://www.digikey.com/product-detail/en/NPPN101BFLC-RC/S5901-10-ND/810012

Prices are more expensive than those of through-hole version. I think board size also needs to be increased.

qelloman commented 8 years ago

@hrldcpr Why did you use two different capacitor for VCC? one is 1uF and another is 8.2pF. They are close so it seems like 8.2pF cap is in use.

hrldcpr commented 8 years ago

@qelloman good question, I wondered about that too since it seems like it would be equivalent to a 1.0000082µF capacitor, which makes the 8.2pF seem pointless… but it's from the XBee documentation, page 22:

To help reduce noise, place a 1.0 μF and 8.2 pF capacitor as near as possible to pin 1 on the PCB.