led + arduino "running light" (very simple, good for beginners)

hello 
so this is my first arduino project. it is very very simple and it is good for beginners
basicly its just leds hooked up in a row to make a running light

Step 1 Materials

-8 x Led (I used 3V Leds because i didnt have 5v ones)
-Arduino
-Breadboard
-Jumper Wires

Optional:
-Prototyping Shield

Comments

[masprotech]

I have been looking for this for a while now...... All others have been over done this is simple and to the point Thanks very much

[ibecake]

Just did this as my first arduino project excellent start big return for small input.
Great Instructible.

[snotty]

Nice easy to understand code. This is great for beginners.

Here's a sneaky trick for your resistor: put one resistor in series with your ground wire on the negative side of your LEDs. This is not going to be good if you reprogram to have all of your LEDs on at once but it's better than nothing. Ideally you'd have one resistor per LED but it's better to have some safety than none.

I blew the USB chip on my Arduino once doing something like this. It was bad news.

Again, nice simple project :)

[jman 31]

Maybe I am missing something, but shouldn't you have a resistor in series with each of those led's.

[quaddel]

why? because i use 3v ones?

[frank26080115]

You should always limit current through the LEDs. To prevent damage to the LEDs and prevent damage to your microcontroller pins.

[jman 31]

Yep frank26080115 is correct. First you will drastically reduce the life of your LED which isn't that big a deal because they are cheap, but the microcontroller would be the big worry. Diodes don't limit current so there is basically just a short to ground. You may get away with it for a while if you are just flashing the LED's, but it will catch up to you eventually. basically any resistor from 470 ohms to 1K should work.

[quaddel]

ok i will change it

[jman 31]

Definitely keep on experimenting! You will learn as you go and those that have constructive input usually are willing to teach. I learned just about everything I know about electronics through trial and error and input from knowledgeable folks on the internet! :)

[quaddel]

i know but i dont have the correct resistors right now^^

[Bongmaster]

neat :)

[quaddel]

thx