Starting Out in SMT

[stinkbutt]

OK, I've assembled enough through-hole stuff that it's old hat, and I'd like to someday be able to start designing SMD boards. But I've never soldered any SMT parts, and I'm looking for a place to start. After all, you've gotta walk before you can crawl.

I've found a few kits on the internet:

http://www.jameco.com/webapp/wcs/stores ... 2150694_-1
http://www.goldmine-elec-products.com/p ... ?dept=1083
https://www.sparkfun.com/products/10935
https://www.sparkfun.com/products/10446

But none of them excite me too much. I'll probably end up getting the goldmine kit since it appears to have a pile of stuff that's relatively easy to test, but I figure this might be a better place to find advice on starter kits, good ways to get started, etc...

Point of reference: In my life I have soldered two SMT components, a pair of 0805 LEDs. And one was backwards, I think.

[adafruit_support_mike]

As far as general tips go, start with 0805 for your passives and SOIC (.05" pitch between leads) for your chips. Get a decent set of tweezers and a fine-tip soldering iron, then use magnification, good light, and plenty of flux. Tin one pad before placing the component, use that connection to hold the component in place, then solder the other end of your passive or tack an opposing pin of your chip so you can solder the remaining connections in peace.

At that scale, the work really isn't too hard. You'll get comfortable with the techniques soon enough, and then SSOP packages (.025" pitch) and 0603 passives are no longer as scary.


WRT kits: what kind of circuit do you want? I've been kicking around the idea of making a "my first SMT" kit and would love to know what people are looking for.

My thoughts on the subject are:

- The circuit should be relatively simple. Learning to juggle grains of rice is enough of a challenge.. you don't want to test and debug something elaborate.

- The circuit should be relatively cheap. Frying something is part of the learning curve, so let it be a 7c logic chip, not a $17.50 accelerometer.

- The kit should contain multiple copies of the same circuit. The point is to learn physical skills, and that involves repetition. The first one will suck, the second will start to make sense, the third will start to look familiar, and by the fifth you'll start getting the feel of things. This correlates with 'simple' and 'cheap'.

- The circuit should be worth having once you're done with it. No 6-LED blinky Xmas trees.

That last one is where I could use input from other people. What's on everyone's wish list?

[Rochey]

A nice headphone amp that replaces the the one in your ipod/ipad etc.
Higher quality should be easily attainable.

/R

[jersagfast]

Hello, I have a bit on SMT soldering here: http://thecustomgeek.com/2012/06/14/smd-soldering-you-can-do-it/ and here: http://thecustomgeek.com/2012/07/09/one-square-inch-of-goodness/

I do have an SMD kit here as well: http://thecustomgeek.com/store/products/one-square-inch-of-goodness/

The above kit involves soldering a ATmega328P-AU IC, witch is a TQFP package, not to bad, 7 603 size passives, and a crystal that requires hot air or a hot plate. Not too bad, and you end up with something really useful.

The Simon kit from Sparkfun uses 603 components, and the Colorganic Spectralizer kit uses 805 components, and do not require hot air or a hot plate.

805 is a little easier to solder than 603, but I think once you get one, the other comes just as easy. (I learned to solder 603 first) Even 402 does not scare me now.

I hope you have fun in your ventures!

**UPDATE** I was thinking of how not everyone has a hot air station or hotplate, and pre-soldered all the crystals in my kits. I will change the type of SMD crystal in the future so it can be soldered with an iron.

[stinkbutt]

WRT kits: what kind of circuit do you want? I've been kicking around the idea of making a "my first SMT" kit and would love to know what people are looking for. . .That last one is where I could use input from other people. What's on everyone's wish list?

I'm not really of the opinion that you should have circuits that do anything too terribly useful for a learning kit. It's for learning. While it'd be great to make youself something useful, that kind of goes against the grain of feeling free to break stuff, no?

Anyway, if you ask me, I'd ask for a bunch of stupid-cheap stuff. Gimme a trio (monostable, bistable, and astable) of 555 circuits. The former two would probably need a few momentary switches to activate them. Then give me a couple of sinusoidal astable oscillators. It appears that the 555 is available in two (virtually indistinguishable) SOIC form factors. That's my vote, for whatever it's worth.

[adafruit_support_mike]

I'm not really of the opinion that you should have circuits that do anything too terribly useful for a learning kit. It's for learning. While it'd be great to make youself something useful, that kind of goes against the grain of feeling free to break stuff, no?

I was hoping someone would say that..

Anyway, if you ask me, I'd ask for a bunch of stupid-cheap stuff. Gimme a trio (monostable, bistable, and astable) of 555 circuits. The former two would probably need a few momentary switches to activate them. Then give me a couple of sinusoidal astable oscillators.

I have piles (albeit small ones) of such things:



Those are square wave oscillators in 1Hz, 10Hz, and 100Hz. Two resistors, one cap, one LED, a Schmitt inverter, and a buffer. Total parts cost, about 25c.

I have fixed-value current and voltage sources, fixed-frequency sine wave oscillators, arrays of LEDs driven by mosfets (because I always end up wanting a few LEDs somewhere and 'high impedance input, just plug it in anywhere' is nice), switch debouncers, one-shots, on/off toggles, etc.

They're all little things I've found myself wanting while building and testing larger circuits. They aren't exciting in their own right, but they're cheap, handy, and good SMT soldering practice.

If there's enough interest to warrant a run of PCBs and catch the attention of a really high-class Open Hardware distributor (hint, hint ), I'd be happy to make some kits with enough boards and parts for, say, five variants of the same basic circuit, plus a few extra parts for 'learning experiences'.

[adafruit_support_mike]

Actually, I'll go one better than that..

Even if there isn't enough interest to support a commercial product, I'll do some Eagle layouts and basic instructions for the ciruits I have, and put them online. Open Hardware is Open.. if people want to source the parts themselves, there's no reason to hold the designs back.

[adafruit_support_mike]

It's taken me a while to shake things out, but here's the first beginner-friendly SMT design (a six-component square wave oscillator):

http://info.yawp.com/blog/2012/36/smt-t ... index.html

More to come as I get the designs cleaned up for public consumption.

[adafruit_support_mike]

I'm finding that converting designs from whatever-the-heck-I-used-at-the-time to Eagle involves some iteration of design and testing, but the next SMT tool is ready for human consumption:

http://info.yawp.com/blog/2012/38/smt-t ... index.html

It's a pulse-train generator.

[adafruit_support_mike]

Electrically simple, but will give you lots of practice placing and soldering parts:

http://info.yawp.com/blog/2012/39/smt-t ... index.html

Mosfet-driven LED boards.

[vincentp]

thanks for sharing !
don't forget adafruit learning center excellent tutorial(s)
including
http://learn.adafruit.com/smt-manufacturing

[john444]

Hi M Stone,

Very nice (and useful) little pc boards.
I have not finished looking though your web-site.
There is a lot of maker-stuff there, thanks for sharing.

Let us lurkers know when you are set up to allow us to buy some of these.
Making pcb is the tough part of electronics for me.
It looks as if your little boards will make it easier.

Good Luck, John

[stinkbutt]

Wow. It looks like this post developed a life of it's own and went upriver to see Colonel Kurtz.

Sweet!

[adafruit_support_mike]

Wow. It looks like this post developed a life of it's own and went upriver to see Colonel Kurtz.

Sweet!

Heh.. you gave me an excuse to publish some ideas I've had kicking around for a while. Thanks for providing the spark that got things going.

There's more on the way..

[planetscape]

Instructable's Jar of Fireflies was what got me motivated to learn SMD stuff. I went through several of the kits you already mentioned to get myself comfortable with the techniques, but the JoF is a project that, once you hold one, may well hook you into making more. I've probably done 2-3 dozen now, for friends and thank-you gifts. They are very popular.