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Friday 31 December 2010

DS2406 1-wire 240VAC powerswitch

To control my greenhouse heater, which are notoriously bad for keeping a decent temperature i have found, i have added a 240VAC 1-wire controlled socket.  This has been kicking around for a while, but since moving to Linux it has been solid. ( see 1-wire-weirdness )

A nice 3d-rendering of the circuit.

And some bash shell code to control it.

VFD - Vacuum Fluorescent Display

I found some VFDs on ebay and i thought, that would be a great replacement to the USB LCD - bigger and brighter. 

These were NCR 5972s, these are great as they are RS232 controlled (which  is why i needed to add some extra RS232 ports in an earlier post).

I used this document i found for the pinouts.

Initially i wrote the code below on the Mac, but the serial to usb dongles i had didnt like the length of time they were running and died/crashed after a few hours runtime.   On the linux box it has been running for days no problem.

Homemade USB LCD

I used a FT245RL to power a LCD i ripped from a dead UPS.

I was surprised on how easy it was to do, though this is all to do with the FT chip :)

Nicely 'hacked' into the back with rubber bands, hehe

And the circuit if anyone wants it...

And the C code to run it...  (pity blogspot don't syntax color the code)

NSLU2 with header - testing i2c

Here is my test bed slug, with a header added to allow access to the serial ports and i2c interface...

Definately a 'hack'. :)

Can I fix my Macbook Pro PSU?

My MBP PSU died, as it seem all of them do after a while (just google it).  Loads of reviews on the ones sold by Amazon and Apple themselves got 1 star ratings!

So i thought can i open i up and fix it, maybe its a bad capacitor or something???

Well...  after cutting around the sealed unit with my dremel...

NOT!   I don't think Apple want you to.   So i bought a standard looking laptop PSU  (think normal DELL, Toshiba or Fujitsu PSU in black)  but in white with a mag connector.    It's been working fine for few days now.

Adding a 5v and 12v rail to my PC

I wanted to add a 5v and 12v rail to my PC, this removes the need for all the wall-warts (great US term there :)) i use to power various bits also attached to my PC.  Weather station, VFD etc.  (more on those later)

Front view showing the molex standard harddrive connector used.

Now installed into my PC

Adding a 4 port RS232 serial pci card to ubuntu

I bought a 4 port RS232 serial card for my box, the supplier said it was Linux supported.
Though as you can see before it wasn't that clear cut, some fiddling was needed - pretty much like how most devices needed setting in the old Linux days...  before user friendly linux distros.
It said it has Sun1040 chips???  Does that mean anything to anyone?  LOL  As you can see below Linux thinks it is "LSI Logic / Symbios Logic" so not Sun 1040...

Look for the card...

root@ubuntu:~# lspci

Thursday 30 December 2010

1 Wire weirdness

Some time back (over a year now) i decided to build a weather station I could have bought one, but i'm tight and building one from parts is more fun.

It started with my Mac mini, digittemp and a few DS1820 temperature sensors, then it moved onto a NSLU2 'slug' now it's based on a big old Linux box.

On to the weirdness...  On the slug the fuse filessystem never worked terribly well and crashed a lot. So i used the web daemon quite well.  I built a DS2406 240VAC power switch to control my greenhouse heater, but it used to trash the 1-wire network, all the other devices dropped off.

Anyway since moveing to the Linux box, the circuit is solid (so far) and the fuse filesystem is solid.

No idea why it was flakey on the slug, but i'm glad i am off it now.

Circuit below (just exchange the ds2405 for a ds2406)


Well, i've been putting off having a blog for years, they seem a way of self gratification which i'm not into.

But times change and i nee somewhere to save my ideas, and somewhere where my friends can keep up to date with what projects i'm working on.

So this blog is to record what things i'm working on and how far i have gotten with them.

So children lets begin... "Once upon a time there was a guy who like computers..."