Stephen's Weblog

Ah, it’s been a while.

Since I opted to stop posting on a fixed schedule, that seems to have eliminated any hope of regular updates – oh well.

So, I have been largely tied up in a (Very big) project that’s still secret, I’m not saying much about it. But there have been a few bits of progress in other areas – Most notably, I finally got a CNC controller board populated!

Isn’t it lovely?  I certainly think so, after all the work that went into getting this far :)

Sadly, I won’t really get much further at the moment (need to get back to an all-consuming secret project), but this has marked a pretty big milestone in a few of my projects (the reflow controller also works pretty nicely!)

I’ll be sure to take some time and write up these when I make some more progress (or just get sick of working on the more important stuff again)

Progress! At long last!

Over the past month I have been designing a CNC controller for various small projects I’ve been kicking around (oh things like 3d printing, building a pick&place, and some other random thoughts)

Being the hopelessly stubborn sort that I am, I decided to build it from scratch. The design work for something like this is something I enjoy immensely, and while I don’t always get everything right the first time (There are a few inefficiencies, but nothing terrible), it’s been a lot of fun and a good learning experience.

Here’s an image of the final board design, and past the break is a very long thread of text and images showing the steps getting to this point:

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Ah! It’s been 2 weeks again already; Work speed for me always varies a lot, but I’ve been unlucky lately: I put in a lot of effort for one project and then it stalled right near the end. I’ll go back and finish it and write it up sometime soon though :)

In the meantime however, I have received the reflow controller PCBs I mentioned a month ago! Some pictures are up on flickr, one is below – I don’t have it working yet but that will become a priority pretty soon.

Coming next:  I’m currently working pretty hard on a CNC controller for stepper motors and some other things; As usual my ideal is to build my own solution instead of using any existing one, so I’m desiging my own now. I will post a full writeup on it once I have it completed, but don’t want to share any details at the moment.

Not a whole lot has happened since my last post; at least not a whole lot of projects that I’m talking about :)

I’ve been busy working on a Windows Phone 7 game, writing VHDL for one hardware project, thinking through a second hardware project, and will be working on yet another hardware project soon ;) These I will probably post about eventually, but not until they’re further along…

Some of these projects are explicitly going to have the first revision done in 2 weeks though, so I should have plenty to talk about then!

I have started getting set up to compile code for the LPC134x chips that I’m using in everything recently, as I will need to be able to program them shortly – I’ve got the devkitARM toolchain installed and am modifying the GBA compilation toolchain to be able to compile for these devices. Just started that earlier today and not quite done yet.

I’ve also designed circuit boards for a toaster oven reflow controller (including images below) – This is a two-board solution, one deals primarily with switching the high voltage using optoisolated triacs (thanks eagan for pointing me in this direction, I was originally thinking of relays) – The other board is another LPC1342 with a flash chip to store configuration and run data. It has some buttons and an LCD for user interface.

These will be in Laen’s Jan. 3rd order, and I will be trying oven reflow very shortly after they come back :) I also have come up with a few other interesting things to control with this, and will have to report back on my success with that at a later time…

One big thing I’ve been working on lately is bitbox! Bitbox started as just a clever idea, but it was just so interesting that I had to make it :) Bitbox is essentially a tiny music player that will play 8-bit music – sorta like a boombox, but a bit smaller ;)

I still have some software work ahead of me, but here’s the (nearly) final circuit board:

(I say nearly final because I did go on to make some tweaks after taking this image)

Read on for a train of WIP images and more information… (more…)

Hi again,

More projects are incoming – but I have got a few things partway done, here’s one of them:

This circuit board is  a very basic tool that I’m going to use to monitor the SMBUS data in a computer; I have some things I’d like to find in it, but I’m also curious as to what all traffic exists on this bus. I’ve already sent this board to be produced, so should have some results from it in the near future :)

I’ve also been doing some work on PC booting; I’ve written a boot sector that does some stupid stuff; still exploring this space, and I’ll talk more about it later.

Another week has gone by already? Well, I do at least have something to show for it.

So the thing I spent the most spare time on this last week has been designing a FPGA-based PCI card. This is something I’ve wanted to do for some time now (and have an earlier unfinished attempt that was far more complex), but I have recently encountered some inspiration for a board that will be somewhat useful, or at least interesting.

This board isn’t really much of anything special, but it will fill a specific niche, and will be sufficient to try out a lot of interesting things I’ve been thinking of in the PCI space.

So, This isn’t going to be an exceptionally impressive post, but I did collect screenshots from various stages of the board’s development, and  I’ll also discuss the design decisions behind this board.

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Hi again,

As promised, this week’s project entry is much less entertaining;

I did attempt to get this project a bit further today but distractions have taken their toll. Expect this one to come up again in the future :)

So, not too long ago I had the bright idea to build a little USB stick; My motives at the time were apparently highly questionable, so I am here about a month later with a fairly limited use USB stick

One of my major goals behind this project was to have an excuse to work out the details of USB, and try some stuff out, which I’m still doing now. Once I get that done with, I will attempt to explain just how all that works; USB is a bit elaborate, but it’s increasingly interesting and important these days, as serial and parallel ports are becoming more rare. I have another project along these lines too, but it’s quite a bit more low-level.

For this post though, I’m just talking about the hardware design of this project. (more…)

3 blog posts already, amazing – though very shortly I may have to start talking about far less interesting projects, or post less frequently. This is starting to take quite a bit of time, and I’m running out of interesting things I’ve been doing. :)
So, recently I’ve started looking into ASIC design – it’s will still be quite a long time before I can practically start thinking about trying to design my own chip, however, in the meantime some chip reverse engineering has attracted my attention.
Now, I mostly operate from a home-lab environment, and it’s not really safe to involve things like… high concentrations of Nitric acid. But, having recently acquired a decent cheap USB microscope (the Veho VMS004DELUXE USB Powered Microscope), I decided to give chip disassembly a shot for the amusement value. Given my lack of professional tools this has little potential to be really educational, but it was pretty interesting. This is a pretty picture-heavy post,  if that wasn’t clear enough already… (more…)

Another week has gone by, and it’s time for another project!

This week’s project is a little bit more complex than the last one, but it’s still pretty small. It’s a small board that drives an 8×8 LED matrix. It’s actually a pretty silly project because I only have a dozen or so of these LED Matrices around (I’m not sure I can even buy these specific matrices anymore) – I actually bought them back in 2005 – they’re 8×8 arrays of red/green LEDs. They’re organized with a common anode per row, and then red/green cathodes per column. (Davr also got some, and has a number of entries on his blog about his efforts)

Just for fun, I set out to design a board that would sit on the back of the LED matrix and make it easy to drive from a small microcontroller. My design goals were to have current drivers on the common anodes, and provide a shift register to easily configure the other LEDs. I also wanted to be able to easily chain multiple boards together to make a much longer array. (Read on for more details about the design…) (more…)