Building an ITX laptop - Episode 1

I want a laptop that's future proof.  If someone walked up to me and told me that, I'd tell them it's impossible, and buy something cheap so you can save money for the next cheap laptop.  This is because there's no reasonable upgrade path on laptops.  (sometimes you get one or two upgrades...  but that's not a common thing.)

Now, what if a laptop took a standard motherboard?  If that were the case, you could swap out the motherboard as technology moved along.  There's a very tiny motherboard standard that really suits itself to portable installations.  ITX motherboards are the core of the shoebox size computer market.  Some of those ITX cases are even the size of a small book.

People have been strapping monitors to PC cases for decades. And LCD's are now ubiquitous.

Really, that just leaves the power supply as the big issue.  There's no good off the shelf power solution for a portable ITX machine.  And i'm not just looking for "portable."  I want some decent runtime, and maybe even actually to put this in my lap.

I've been thinking about this project since the early 2000's.  I've even bought parts from time to time to support the plan.  (I've got a folder with Ti's simple switchers in 3.3, 5, 12, -5 and -12v..)

This leaves us needing to make a few decisions.

1. Electrical:  ATX power supply, battery charging, battery, display power supply, power reporting to the OS.
2. PC components: keyboard, monitor, motherboard, mouse, wifi.
3. Case design: Can it all fit?  Can it call be cooled?  Can it all be easily accessed?  Does it look good?

Next time, we'll start in on the PC components.

A Cubists Interpretation of the Blinky LED - 4x4x4 LED cube

A few weeks ago, Loclhst suggested he wanted to make a LED cube.  After a little research, I came upon this instructable: http://www.instructables.com/id/Arduino-4x4x4-LED-Cube/  

Localhst and I finally managed to scrounge some time up, and we met at PumpingStation:One for a bit of a hack session.  We made some jigs, and started soldering.  

This is James using my jig to make his own LED cube:

Here's a little bit of Loclhsts handywork.  He's really picking up this soldering thing.

Here are two of my LED layers.  It was about this time that I figured out that I'd need to have some method for bending over the LED legs.

And here's all the LEDs built up into a "cube".  It's more like a big parallelogram.  But who's counting.  ... and get that protractor away from my CUBE.

The legs that stick out the side are the ground pins.  Those let us address each layer seperately.

 Nothing like building a wiring harness at 12:30 at night.  And doing it neatly.  And cleanly.  There's heatshrink tubing and everything!

This was testing the first layer.  You can actually see the arduino board in this shot.  Once it's fully hooked up, there's 20 IO pins in use.

Lets play find the Duemenilove!  It's in there.. I swear!

Localhst didn't finish his.  But he did make a 12v regulated power supply for a soldering ventilation solution.  Ideapdish also gave me the parts to build a box to put my led cube in.  I'm excited to assemble it and get this into a displayable condition!  

Making math sane - PrototypeMachining to save the day.

http://www.prototypemachining.ca/Articles/ElectronicsMathSimplified.html

PrototypeMachining went ahead and started pulling apart the eccentric symbols and letters used for electronics math.  He's put real words, and layed them out like you were taught to write equations in math class.  This, is seriously useful stuff.

More samsung caps. Dell monitor repair

Well I found a dead monitor at work.  I cracked it open and found three dead caps.  I replaced them, and viola, working monitor.  Now... I need to ask if I can keep it.

A minty boost.

A few months back, I brought some friends to a Mitch Altman soldering class.  He brought kits, and while my friends were doing theirs, I decided I'd make something. 

Thank you ladyada.  Well, her company provided the kits.  And here's the kit I built Minty Boost. I assembled my minty boost into an altoids tin.  There's room for a spare set of cells in there too.

Testing sensors.

Well I bought some pressure sensors.  In hopes of building my own altimeter.  When motorola says 5-25mv output, they aren't kidding.  The mpx2010 has an output that seems perfectly tuned to feed an opamp.  Time to learn opamps.

Here's a link to the datasheet: MPX2010

Playing with digital glue: using an arduino as a really expensive voltmeter.

Last Thursday I met up with Loclhst to show him how to use analog sensors with his arduino. 

The process started with testing the photoresistor and thermistor on the bench with a voltmeter.  We then set them up in a voltage divider, and fed 5v across them.  That got us a voltage output we could send to the arduino. 

Then we hooked up the voltage dividers to the arduino, and we got real values. 

Then dan wanted to get his display working.   After we discovered I had a wire crossed, the display worked fine.

New tool time. An O-silly-scope. - A DSO Nano v1.5

I've got piles of voltmeters. Most of them are hilariously cheap, but when an accuracy of .1v is enough, the $3 voltmeter from harbor freight will do the job.

Voltmeters are grand, but they are very poor at showing you charge and discharge curves, and tell you absolutely jack about waveforms. That's where an oscilloscope comes in to play.

I have been lusting over the pocket oscilloscopes for a long time. And slowly the price has been coming down to the "why the heck not" level. About two weeks ago I decided that a DSO Nano had to be mine. $66 later, and four days of waiting, and it was.


Well there we go. You also get a little felt bag and a USB cable. But those are the big things you get in the package. No documentation at all!

They claim that it will accept 80v peak to peak. And that it has a 12bit DAC. Also they claim that it's got 1Msps.

I figure that means I can reliably look at 100khz signals.

On the subject of signals, it has this nice little test point on it. The test point is adjustable from 500hz to 2000hz.


Here's the DSO checking out it's own test signal. You can see it overshoot and the discharge curve. I wonder where that tail is coming from...

Now I wanted to try it with a really fun. The only thing I could think of that I had that would output a nice signal was my arduino. I loaded up the servo sweep sketch, and checked it out.

The servo signal is a pulse, every 20ms, that's between 1 and 2ms wide. I made a video of it. http://www.youtube.com/watch?v=YlIW7AvBg0Q

I posted on the EEvblog forum, asking for ideas of how to test, and exercise it. http://www.eevblog.com/forum/index.php?topic=4546.0

So it looks like I am going to make a joule theif.