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Topic: Bus Pirate v3b FTDI (Read 7193 times) previous topic - next topic

Bus Pirate v3b FTDI

I posted this elsewhere earlier, but wanted to start a new thread to document any continued development.

Here's the original thread:  (http://http://dangerousprototypes.com/forum/viewtopic.php?f=28&t=1734),
The original blog posts:
http://http://schazamp.wordpress.com/2011/01/30/bus-pirate-v3b-ftdi/ (original post)
http://http://schazamp.wordpress.com/2011/01/30/buspirate-v3b-ftdi-0-2/ (minor pcb update)
http://http://schazamp.wordpress.com/2011/02/23/buspirate-v3-ftdi-0-2-photos/ (gallery of assembled version)

Re: Bus Pirate v3b FTDI

Reply #1
Nice job, thanks for the pictures. Do you have a lot of experience soldering SSOP and 0805?
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Re: Bus Pirate v3b FTDI

Reply #2
I've done one SSOP on a breakout board, and a few SOIC, and one 0805.  This is really my first surface mount project of any substance.  I had been daunted by the size of the stuff to work with, but with the right tools (fine tweezers for placement, and a stereo magnifier for inspection) it's really not bad at all.  The hardest part is still to keep from dropping or brushing away the components (or exhaling too strongly) before I solder them in.

I found that things went a lot more quickly soldering a bunch of 0805 components, since I didn't have to mess about with placing, flipping, and clipping leads.  I'm definitely going to do more surface mount stuff on my projects in the future.

Re: Bus Pirate v3b FTDI

Reply #3
Once you start it's really hard to go back, for all the reasons you listed. Also it's really cheap :) We recently moved to 0603, it's ridiculously cheap for most passives, and I've taken to buying reels when I need a value.
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Re: Bus Pirate v3b FTDI

Reply #4
We switched when I just ordered a 0805 resistor and capacitor kit :(

I do have 'the problem' with 0603 that components tend to shoot away when picked up with tweezers :) (I came from 0805 sized components)

Re: Bus Pirate v3b FTDI

Reply #5
How would you compare the difficulty of doing 0603 by hand to doing 0805?  Just looking at the price differences makes me want to do the same thing, but I'm a little concerned that my home PCB fab process won't let me do that small (at least, won't let me route traces between the pads, though arguably, that's not really easy to do consistently with 0805, either).

Re: Bus Pirate v3b FTDI

Reply #6
Quote
won't let me route traces between the pads

I won't even do professional boards like that, so I can't speak to it :)

I think they are easier to solder because you sometimes only have to heat one side and it reflows the other pad too (because there's so little metal to heat).  They are easier to send flying.

I used to do it without magnification, but lately I use the head visor from adafruit and love it, it just makes it easier to handle everything:
http://dangerousprototypes.com/docs/Dan ... rk_station

Tombstoning was a problem when I first started, but not so much any more.
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Re: Bus Pirate v3b FTDI

Reply #7
Well it is a bit smaller then 0805, obviously :)

If you got a good pair of tweezers and good eyes it is both pretty well doable. Using lots of light and a magnifier will help massively. I don't have experience in making my own pcbs, but it depends on how small you coudl reliable etch. Bigger is better I guess :) but most tracks are smaller then 0603 parts so prolly it doesn't matter much.

Re: Bus Pirate v3b FTDI

Reply #8
[quote author="ian"]
Quote
won't let me route traces between the pads
I won't even do professional boards like that, so I can't speak to it :)
[/quote]

My toner-transfer boards are all single-sided, and it's hard to give up the option to route between thru-hole resistors, which can really cut down on the number of vias you need.

Quote
I think they are easier to solder because you sometimes only have to heat one side and it reflows the other pad too (because there's so little metal to heat).  They are easier to send flying.

I need to get a white poster board or something to put under my work surface, it's so hard to find things when the get dropped or brushed away.

Quote
I used to do it without magnification, but lately I use the head visor from adafruit and love it, it just makes it easier to handle everything:


I have an old visor like that from a medical supply, and it's great.

Re: Bus Pirate v3b FTDI

Reply #9
Opps, I thought you meant between the pads of 0805 and 0603 devices. I don't do that. Between through-hole resistors sure. You can fit a village under there :)
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Re: Bus Pirate v3b FTDI

Reply #10
I have released BusPirate-v3b-FTDI-0.3, which has:

* room for a shrouded I/O header
* Sparkfun's locking header rows (see http://www.sparkfun.com/tutorials/114)
* more clearance around voltage regulators, for easier assembly
* improved label size and positioning

I don't intend to produce any more boards, unless someone wants me to put together a kit for them, but Ifelt like these updates were worth making anyway.

You can find the zip distribution here: https://github.com/schamp/Schazamp/downloads
Or check here for the source: https://github.com/schamp/Schazamp/tree ... e-v3b-FTDI

This one comes in at 1.425" x 1.110", which is ~1.58 sq. in., which would be about $7.90 for three at Laen's DorkboxPDX service.

Re: Bus Pirate v3b FTDI

Reply #11
I replaced the vertical 6-pin FTDI header with a horizontal one, and now with a header extender (really just a 6-pin passthru header) it fits just fine in my enclosure:

[attachment=1]

[attachment=0]

I love those pass-thru headers, they work great as extenders, or when I need a normal header but only have a single-sided (i.e., homebrew) pcb to attach it to.

More photos here: http://schazamp.wordpress.com/2011/03/0 ... enclosure/

 

Re: Bus Pirate v3b FTDI

Reply #12
Nice work, I'll post an update on the blog. Thanks for sharing!
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