Daily Archives: February 16, 2010

Arduino, LED-s, LM35 and DS18B20 or temperature sensors. 2

Checked out my local electronics store http://www.oomipood.ee yesterday and got some stuff. First, a breadboard and some wires. Also got me a soldering iron. Those are just for testing. At least I do not have to twist wires together now. Then I thought, LED-s are cool for something, right? There is a nice site http://www.ladyada.net/learn/arduino/lesson3.html. So I did get 10 1/4W 1K ohm resistors, and some leds, specifically 2 red, 2 blue and 2 green. 3mm and somewhere near 2000-4000 mcd.

First Steps

Looking around, I decided to get one plain Arduino Duemilanove. Luckily a local dealer is near so I did place an order on it at 15:48 and made a bank transfer. At 17:03, less than 1.5 hours later I got an e-mail stating that I can get my hands on it around 19 o'clock. After a quick call, I got confirmation, that my transfer had gone through and couple of hours and a small trip later I was a enthusiastic owner of an Arduino Duemilanove. Great thanks for http://ittgroup.ee/ and Zazou in particular.

Why Arduino

Why start playing with Arduino? For a long time I was looking for a way to get temperature readings from outside of computer case and draw graphs of them. Specially with linux. There are a lot of ready to use temperature readers, but all of them have some flaws.

Fast way to create or assemble mdadm devices

Booting from cd and no /dev/md devices? First, correct kernel modules are needed. modprobe raid1 If configuration uses different raid, then a different raid module should be loaded. Be it a raid 0,5,6 or whatever. Devices can be made then mknod /dev/md0 b 9 0 mknod /dev/md1 b 9 1 and so on. As many of them as needed. From this point on door is open for mdadm create,assemble or whatever is needed. Creating a device goes like this: mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sda2 /dev/sdc2