Random Gadgetry

ATMega8

2010-04-08T07:09:00.004+03:00

I made a parallel port programmer for a ATMega8-16PU (16MHz DIL package) micro controller I had lying around for a while. I used about an hour making a nice looking dongle with a DB9-DB25 case to house the 4 resistors required for the programmer (I made the stk200 variation with 330 ohm resistors). But imagine my surprise when I took the dongle in my hand and went around the computer case to connect it.

No LPT port, WTF?! How did I miss that one? I just recently changed my mobo since the old one kinda broke, and now the only COM-port and LPT-port exist only as a header on the mobo and not in the backplane. Great.

I managed to find from work a printer extension cable that had 2 DB25 connectors connected via ribbon cable which I clipped from the male end and replaced the connector with a female header to plug to the mobo.

I had a simple prototype board housing the micro controller, where I plugged the programmer and made connections to 1 red led for power indicator and another one for a port to indicate successful programming. I used some ready made blink program pulled from some website with its make-file (I used WinAVR as the programming environment since the programmer was said to be supported by it very easily). I compiled once, tried to program the mega8. But the make-file still needed some tweaking since it was made to address /dev/ port under linux, which I changed to LPT1 as the debug info box in WinAVR suggested. Next program try worked perfectly, the program went to the mega8 and the led I put on one of the ports started to blink like expected.

That's it for now, more to follow...

Happy New Year 2010!

2010-01-01T01:19:00.000+02:00

It's been a weird year.. With the economic crisis mixing things and all. Atleast I have managed to stay now over 2 years in the same job, and I'm feeling pretty happy about what I do.

I finally got the other half of my summer vacation money, and spend that on crosscountry skis that I have been wanting for a long while. Tomorrow I'm going to start trimming the holiday fat...

Free online tests - not that accurate

2009-07-08T17:04:00.001+03:00

I used a free Ishihara Test for Colour Blindness today... Just for the
fun of it. Well, I was really surprised of the outcome. The test
insisted that I got a 80% score, and that I had green-red blindness.
Image what shock I was in, since I always thought there was nothing
wrong in that department.

I had a strong doubt though, that the test was somehow fucked up. I made
a google search on Ishihara Test, and found all pictures used in the
free test, and compared the answer keys provided with that I had entered
as the answer. After cross-checking these differences I found why I got
a poor result.. Two of the pictures on the test were entered correct by
me, but the test flagged them as wrong. The person that made the test
must have accidentally copy-pasted the code poorly and was checking in
the 2 pictures the value entered for the first picture.

Sounds like an error I might have done my self, but still... Lucky I
dodged that bullet after all :-D

DVD scratch repairs the simple way

2009-07-07T01:29:00.000+03:00

I got in my hands today a DVD that had an annoying scratch that prevented my cheap dvd-player from reading past it, got at least 6 moments in the movie where the picture kept blurring in artifacts and the movie skipped annoyingly in microsecond bits after trying to read it for minutes.. So I decided to go and try a repair that I used once before to make one of my oldest cd-rom games readable. Toothpaste!

Of course I don't mean I just smeared some toothpaste on the dvd and jammed it back in, no. But I used a bit of the toothpaste on my finger and with a help of few drops of water with gentle pressure I smoothed the surface around the scratch enough for the laser to get past it. The whole dvd was 100% playable after wards. Sure, there is all sort of more professional solutions out there, surface grinders and solutions you can use to get the scratches out totally. But I'm way too cheap for that. Besides the toothpaste worked just fine and was available.

And on the plus side, now the dvd smells minty fresh...