Homebrew_PCBs

----- Original Message -----

> Is it possible to hand solder one of these

----- Original Message -----

> They already have to put some components in
> SMD reel strips to keep them.

> Stupid people! why can't they use DIL?

>
> You could reflow it in a wok. Solder paste is (relatively) cheap:

> http://www.stencilsunlimited.com/solder_products.php. As to

> less than professional, I would have to agree to the extent that

> certification is unlikely. Otherwise, it works just fine. It's no

> controlled than hot air, and infinitely better than hand soldering.
>
> ----- Original Message -----
> From: "Anthony" <toftat@c...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Wednesday, January 25, 2006 9:24 AM
> Subject: [Homebrew_PCBs] Making a homebrew board using QFN packages
>
>
> > After great success with through hole boards, I have a new project
> > starting, one of the components I want to use is the nRF905 from

> > semiconductor, the '905 is only available in a QFN package which
> > doesn't seem to be the most hobbiest friendly of formats. As far

> > can tell there are no legs on it...
> >
> > Is it possible to hand solder one of these, filling in the gap?

> > make sockets for them (I have found prototype sockets on line but

> > $500 each they are a bit out of budget)
> >
> > Any ideas folks?
> >
> > Anthony
> >
> >
> >
> >
> >
> > Be sure to visit the group home and check for new Links, Files,

> You could reflow it in a wok.

> Solder paste is (relatively) cheap: $16

----- Original Message -----
From: "derekhawkins" <eldata@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, January 25, 2006 12:37 PM
Subject: [Homebrew_PCBs] Re: Making a homebrew board using QFN packages


>> You could reflow it in a wok.
>
> Toaster oven would be better. Saw a nice infrared convection toaster
> oven with digital temperature display and controls, if only it was
> programmable.

Better in what way? If you're buying new, sure, get the toaster oven. I had
an old skillet on hand, and it stores very compactly. The "face" is open so
I can readily watch it cook, and even point an IR thermometer at it if I
want. But I haven't found a need. Medium flame, anywhere in the middle third
of the dial, gives a usable temp profile.

>> Solder paste is (relatively) cheap: $16
>
> That's $16.00 for 1.2 ounces BTW.

Yup, and it has a shelf life of about a year. 35 grams is more than a
non-production shop can use in that time. I'll likely throw out more than
half of it. In the meantime, I gain all the benefits. What can be simpler
than mashing the tiny parts approximately into place, and then stir frying
for 4 minutes? (Peanut butter and jelly sandwiches come to mind, but not by
much.)

> If you're buying new, sure, get the toaster oven.

----- Original Message -----
From: "derekhawkins" <eldata@...>


>> If you're buying new, sure, get the toaster oven.
>
> What's wrong with an old toaster oven if one just happens to have one
> on hand?

Nothing's wrong. Was just wondering what made it better.

> Tapes are really intended for pick and place machines. But you knew
>
> that. A cut tape purchase simply means they cut a piece off with the
>
> quantity you ordered.

> Yes, but they can't simply put them in a box with some antistatic
> foam these days

>
>
> Yes, but they can't simply put them in a box with some antistatic

>
> I just bought the Sparkfun MIRF units. They are nice. I've been
> experimenting with cheap RF units and the antenna requirements can
> make or break the whole system. The MIRF have them built in, making
> much simplier implementation--once you get past the configuration bits.
>

----- Original Message -----
From: "alan00463" <alan00463@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Thursday, January 26, 2006 2:28 PM
Subject: [Homebrew_PCBs] Re: Making a homebrew board using QFN packages


> --- In Homebrew_PCBs@yahoogroups.com, "bob_ledoux" <bobledoux@p...> wrote:
>>
>> I just bought the Sparkfun MIRF units. They are nice. I've been
>> experimenting with cheap RF units and the antenna requirements can
>> make or break the whole system. The MIRF have them built in, making
>> much simplier implementation--once you get past the configuration bits.
>>
> I take it you're referring to the nRF2401A transceiver pair pictured
> here: http://www.sparkfun.com/shop/index.php?shop=1&itemid=396
> ?
> 1Mbps is indeed an impressive throughput for $19.95. What exactly
> are you using them for, if you don't mind my asking?

I'm using them as well, for a sports training aid, communicating between a
sensor unit (MSP430) and a processing/display unit (ARM). I'm only using
them for the prototypes, of course, I'll just use the chips for production.

Leon

----- Original Message -----
From: "Jim Miller" <jtmiller2@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Thursday, January 26, 2006 7:48 PM
Subject: Re: [Homebrew_PCBs] Re: Making a homebrew board using QFN packages


> They're not made for humans at all anymore. They're made for pick and
> place
> robots. I just bought a little memory stick at Walmart and it has a clear
> plastic case. Inside I can see surface mount resistors which must only be
> 2mm or less long and 1mm wide.
>

Murata is producing 01005 capacitors, that's 0.4 mm x 0.2 mm x 0.2 mm!

Leon

> They're not made for humans at all anymore. They're made for pick and place
> robots. I just bought a little memory stick at Walmart and it has a clear
> plastic case. Inside I can see surface mount resistors which must only be
> 2mm or less long and 1mm wide.

> Inside I can see surface mount resistors which must only be
> 2mm or less long and 1mm wide.

>
> They're not made for humans at all anymore. They're made for pick

> robots. I just bought a little memory stick at Walmart and it has a

> plastic case. Inside I can see surface mount resistors which must

----- Original Message -----
From: "derekhawkins" <eldata@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, January 27, 2006 3:56 PM
Subject: [Homebrew_PCBs] SMD popular component sizes


>> Inside I can see surface mount resistors which must only be
>> 2mm or less long and 1mm wide.
>
> 0805 - 2 X 1.25 mm
> 0603 - 1.6 X .8 mm
> 0402 - 1 X .5 mm
> 0201 - .6 X .3 mm
>
> Currently I buy and hand solder down to 0402s (small quantities).
> Down to 0603 is a piece of cake but problem with 0402 is visual
> confirmation of proper solder joint and for that I either use a
> camera (macro shot) or microscope. Just using a DIMM isn't good
> enough.
>
> This is coming from someone who needs glasses in order to read or see
> just about anything properly in a 3' radius. Those with younger eyes
> will be amazed at how something that appears daunting at first soon
> becomes a walk in the park. Many of us can probably recall when
> soldering even a 1206 (3.2 X 1.6 mm) seemed like an impossible task.

I routinely use 0805 and don't have problems with 0603, although I'm 63. I
do need to use plenty of magnification, sometimes a microscope is necessary.

Leon

> I routinely use 0805 and don't have problems with 0603, although I'm
> 63. I do need to use plenty of magnification, sometimes a microscope
> is necessary.

>
>
> I routinely use 0805 and don't have problems with 0603, although I'm

> do need to use plenty of magnification, sometimes a microscope is

> Provided you're definitely hand soldering and not reflowing, a "trick"
> to use for easy visual placement of these small components is not to
> use standard reflow pad layouts. Instead, import them into your library
> editor, modify them accordingly and save as new HS (or whatever)
> layouts.

----- Original Message -----
From: "Dave Hylands" <dhylands@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, January 27, 2006 5:18 PM
Subject: Re: [Homebrew_PCBs] Re: SMD popular component sizes


> Hi Derek,
>
>> Provided you're definitely hand soldering and not reflowing, a "trick"
>> to use for easy visual placement of these small components is not to
>> use standard reflow pad layouts. Instead, import them into your library
>> editor, modify them accordingly and save as new HS (or whatever)
>> layouts.
>
> What would the changes be in the "modify them accordingly" step?

Make them a bit longer. I often do this with the pads for SM chips.

Leon
---
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> What would the changes be in the "modify them accordingly" step?

> > What would the changes be in the "modify them accordingly" step?

> 1. Lengthen the solder area as Leon indicated;
>
> 2. Shorten the width to just over .5 mm
>
> 3. Shorten the pad area beneath the chip so that the contact area on
> each side of the chip ends where the pad ends under the chip. In
> other words, for 0402, only about .5 X .2 mm (W X L1 or L2) of the
> pad is under each side of the chip.

>
> > You could reflow it in a wok.
>
> Toaster oven would be better. Saw a nice infrared convection

> oven with digital temperature display and controls, if only it was
> programmable.
>
>
> > Solder paste is (relatively) cheap: $16
>
> That's $16.00 for 1.2 ounces BTW.
>
>
> --- In Homebrew_PCBs@yahoogroups.com, "Mike Young" <mikewhy@s...>

> >
> > You could reflow it in a wok. Solder paste is (relatively) cheap:

>
> --- In Homebrew_PCBs@yahoogroups.com, "derekhawkins" <eldata@m...>
> wrote:
> >
> > > You could reflow it in a wok.
> >
> > Toaster oven would be better. Saw a nice infrared convection
> toaster
> > oven with digital temperature display and controls, if only it

> > programmable.
> >
> >
> > > Solder paste is (relatively) cheap: $16
> >
> > That's $16.00 for 1.2 ounces BTW.
> >
> >
> > --- In Homebrew_PCBs@yahoogroups.com, "Mike Young" <mikewhy@s...>
> wrote:
> > >
> > > You could reflow it in a wok. Solder paste is (relatively)

>> > > You could reflow it in a wok.
>> >
>> > > You could reflow it in a wok. Solder paste is (relatively)
> cheap:
>> $16
>> > at
>> > >
>> >
>>
>> You may be interested in an article that appeared in the Circuit
>> Cellar magazine, July, 2004, Issue 168. The author described the
>> circuits required to convert a toaster oven to a reflow oven,
>> complete with profiles, and down loadable software.
>>
>> Dave Miller
>>
>
> Sorry, I was getting caught up after being out of town for a few days
> and did not see that this had already been discussed.

>
>You may be interested in an article that appeared in the Circuit
>Cellar magazine, July, 2004, Issue 168. The author described the
>circuits required to convert a toaster oven to a reflow oven,
>complete with profiles, and down loadable software.
>
>Dave Miller