Speedometer for my cat

I got an funny ide from a youtube clip.
source:
http://beta.ivc.no/wiki/index.php/LED_Bandwidth_Monitor
https://www.youtube.com/watch?v=oOapRE5BkuI

I think it's a funny ide. to use IC led strips to show a value.
so I'm thinking about setting up a speedometer in the middle of my hall, throw a little toy and se the speed of the cat on the same type of bar as the Bandwidth monitor.

Now i get it! resistors...

I have always seen people using 100 ohm resistor to a simple led, but I have never understand why. I have use led many times without resistor and no problem.

but yesterday i got it!
From this:

To this:

YES. it's on!











My lab board are connected to a PC and webcam, so I and a friend far away still can do some grate experiments. On it right now: Arduino mega, 433mz transmitter and receiver, 5 leds(without resistors....) and LCD screen.

Now i love my RepRap!

Before the upgrade, the bes layer high I culd use was 0.25 mm if i try using 0.2 It's only get right to hell.

and now I succeeded on fist layer 0.05 and 0.1 without a problem! i will try 0.01 later.

but 0.05 is awesome!

SO here is some picture of the result.
 I still have bitcoin mining headbed an today I install led lights! as i controll with with Fan control in repetier-host.