Agreed: if you have enough space, oversize pads for the SMD components will make it significantly easy to solder yourself. Also add some space between components since you have some room.
if that crystal is about the same as the ones on the bpiphany controllers (it looks like it) then it might not be that hard to solder. Reflow would make it easier though You can also pre-heat the PCB and solder it first. I recommend tinning one pad, placing component, reflowing solder with iron, then manually soldering the other pads. I've only done two, but it wasn't so bad.
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Why not a 32u4 for the uc? It's the one that the teensy uses and so almost all the firmwares are written for it already.
I have an oven for baking will this work to smd solder the parts?
and its a 32u4 lil typo sry ^^ i took this one because you guys use it all the time.
and about the crystal despise having a small footprint is the footprint correct im having troulbe understanding the datasheet. have you a sugestion which i could use instead to make it easy to solder.
It could work in a normal oven but I wouldn't recommend it.
The reason is that the oven doesn't have good enough thermal regulation to reflow the parts without destroying them via heat.
Here's some info from the datasheet:
Show Image
(http://i.imgur.com/pBExqmc.png)
So you need to preheat to 150C, then ramp up to ~200C over 150 seconds, then increase the rate to the oven's max and hit 260C, and hold it there for no more than 10 seconds, then shut the oven off and open the door for some cooling (then close the door to avoid thermal stress). I'm sure you can't do that with a conventional oven (that's why DIY reflow ovens have a thermocouple in there with a microcontroller controlling it). You might be able to heat it up so as to not damage the PCB, but I wouldn't count on it as a "sure thing".
Also included is the suggested soldering pad of the crystal. Just eyeballing it on your pictures, it looks compatible, but I don't have any scale or way to measure it. Just check it on your PCB program and make sure it matches. If your pads go further "out" a little, it shouldn't affect things.
As for the exact dimensions, the pads appear to be on 2.3mm * 1.8mm centers and are 1.1mm * 1.3mm in size, according to the picture.
Ok then a normal oven wont do it ^^.
And i think i got the pads wrong like i dont know if the connections are made correct if pad 1 is up right or where ever.
But since this crystal is hard to mount ill probably want to go with one that goes trough the pcb you have any sugestions like a spescific part?
Ok then a normal oven wont do it ^^.
And i think i got the pads wrong like i dont know if the connections are made correct if pad 1 is up right or where ever.
But since this crystal is hard to mount ill probably want to go with one that goes trough the pcb you have any sugestions like a spescific part?
TH crystals are much easier, though I found soldering the microcontroller harder than the crystal.
I would not recommend a TH USB plug, 'cause fine pitch TH can be very difficult. I think the SMD version is actually easier :P
for the pads, if you look at the datasheet, two of the crystal ones go to the case (I think traces are supposed to go to ground for better shielding, but I dont think that level of paranoia is required.) and the other two (at a diagonal) are for the actual crystal. Since it's at a diagonal, you can mount it either way on the board. Just make sure the topright and bottomleft pads go to the crystal. the topleft and bottomright can do nothing.
Though I think I will have to doublecheck this: I haven't actually made a PCB before. I recommend getting a second opinion or doublechecking yourself before you go get one made.
I just doublechecked the Datasheet and this appears to be correct. I would post a picture of it, but imgur apparently wants to quit working all of a sudden.
edit: here you go:
Show Image
(http://i.imgur.com/Z18auIU.png)
So the pins that are grounded to the case are attached to one side of a capacitor over to the left there it seems? while the pins that "are" the crystal go to 2 pins on the microcontroller. This may or may not be the configuration you need. Do you have the schematic?
edit2:
Oh this is that build with the awesome case! Sweet! I looked at the other topic looking for a schematic, but wasn't able to find a "good" looking one. Not sure if the xtal1 and xtal2 pins needs the required capacitor or if it has one internally.
Do you mean something like this: http://www.distrelec.ch/de/Buchse-gewinkelt-mini-USB-B-5-P-W%C3%BCrth-Elektronik-65100516121/p/14257103?q=usb&filter_Anschlussart=SMD&page=3&origPos=1029&origPageSize=10&simi=97.98 (http://www.distrelec.ch/de/Buchse-gewinkelt-mini-USB-B-5-P-W%C3%BCrth-Elektronik-65100516121/p/14257103?q=usb&filter_Anschlussart=SMD&page=3&origPos=1029&origPageSize=10&simi=97.98) ?