some basic questions about the hardware

hi, i’ve just ordered a arduino starterskit and now I’m wondering about the strenght of the hardware, I have a ton of leds lying around here and an unlit staircase I have 2 free push switches in my hall and now I’d like to do the following:
when i press the one in the hall the stairs (16 in total)
lite up one by one from the bottom to the top and then fade back out.

when i do it on the 1st floor: same but from top to bodom.

is it possible to do it with arduino alone or will i alot of other hardware.

thx in advance!

is it possible to do it with arduino alone or will i alot of other hardware.

It will be too much current for just an arduino you will have to power the LEDs through an external source and use transistors to switch the LEDs with PWM signals.

yeah figured out as much when thinking about it, but can an arduino pmw be used for 16 leds at a time or will it have to be 1 by on my main goal is

first step 0 - 50 % on 50% second led starts 1st goes to 100% at this time the second one is on 50% etc you catch my drift :D

btw whats the max amp that a arduino can handle (frmo starter kit)

depends on where its going tru, the pins can handle a absolute max of 40ma each (dont), the chip as a whole can only handle 200 or so ma, whereas the voltage regulator can deal with 250-300ma (really more depending on factors) and usb could do from 300-500ma

thx for the info, you wouldn't happen to know if my first little project would work thx

You will need additional hardware to make your project work. As mentioned you will need transistors to do the switching for power But you will also need an additional IC or 2 to control all 16 strings of LEDs. I think a couple of 74HC595 Shift Registers could do the trick for you.

Which starter kit did you get. The one offered by Makershed or the one available in Europe and the UK? If you have the UK one then you have the parts you need and the guide to go with it. In which case you should look at Project 15 of the guide for how to use the 74HC595 IC. Otherwise go here and check out Project 15.

That at least helps with the hardware needed. Coding will be a whole different story.

thats one nice little book!

this is my starterskit :)

i'm loving al the possibilitys i see with arduino its endless :D i'm gonna pimp my house :D

i just saw some examples: i have an iphone and my girfriend has an ipod touch, mean i'm never getting up again :D

btw Grumpy Mike, may give short blunt answers (really tho with a name like that..) but its amazing the amount of knowledge that man dumps on this forum every day

and since you asked, yes it will work, but yea you will need external hardware, and some good planing

the hardware that you would need shouldn't be TONS, nor should it require a huge investment, the shift registers mentioned would run you about 1.49$ each on sparkfun (or 60 cents each at digikey), and I just got 100 transistors from digikey for 13$ shipped

you would also need resistors, amount depends on how you go about wiring it ...

now that you have some form of gameplan there is a few things to do

1) get some parts mentioned to play with if you don't already 2) learn the basics of a shift register, a transistor and PWM 3) look at your staircase and start planning how you want to mount these things and route wires

I keep a copy of the guide in my iTouch using a PDF reader. Its called PDFreader by YUYAO Mobile Software. Can't rememebr if its one of the free ones on the app store or if it was $0.99.

Hi jeroenvdd,

depending on how much you want to build yourself and how much money you can spend, you should have a look at the Rainbowduino which already features the mentioned transistors:


Glad you enjoy the guide Digimike :)