I have a question about the current draw from the arduino 5v pin. Is it true that i can pull around 450mA from that pin(Usb powered, arduino uno itself use around 50mA or something close to that, so that leaves me 450mA IF all the digital pins are turned low).
No problem, I just thought it was weird because I was sure I made the post . Anyway, my next project will be 5x5x5. I already ordered some shift register to experiment with and learn the basics of them , I probably going to use shift registers on my 3x3x3 cube first to make sure I understand the programming and the way the shift registers work.
All the components are send today! Soon I will start building the cube .
A little programming question. What will happen when I don't use a delay between switching on and off the LED. I would guess it wouldnt turn on the LED because it's been turned on and off too fast. Will I do damage on any components if I don't use delay.
And it's true the arduino pin can take up to 200mA? So I will be able to put on 9 LEDs on 1 plane ( 9 * ~15mA= 135mA). Thanks for the help again .
Thanks for the explanations, now I understand why I needed it.
I got another question about the 13th pin from arduino. According to arduino pin 13th has an built in resistor so I can directly put a LED to pin 13 and ground. When I connect a column on pin 13 does the LEDs shine less bright because there is an extra resistor built in on pin 13(my 220ohm resistor + arduino uno pin 13th resistor?)
Is it possible for somebody to explain me why I need to use a resistor on the base from the transistor? I did alot of reading about why a resistor is needed on the base from the transistor (as NPN switch), but I keep seeing different answer on different forums this makes me understand it less and less. So if someone briefly can explain why a resistor is needed on the base (and how you calculate it) I would be very happy with it !
sorry for the newbie questions, still in the learning process
Thanks to you all! Then I will get resistor aimed @15mA. As well with the programming I will only lit up 1 layer at the time !
Control question: If I want to lit up the whole cube, I need to do the following: -Select layer 1 (turn off layer 2/3) -Turn on all LED columns -Turn off all LED columns -Select layer 2 (turn off layer 1/3) -Turn on all LED columns -Turn off all LED columns -Select layer 3 (turn off layer 1/2) -Turn on all LED columns -Turn off all LED columns
Or is this possible as well? (I'm newbie in programming as well ): -Select layer 1 (turn off layer 2/3) -Turn on all LED -Turn off layer 1 -Select layer 2 -Turn off layer 2 -Select layer 3 -Turn off layer 3
Ok then I will lower the value from the resistor to around 180 ohm (to be in the middle of safe and bright ). So you are saying I can switch on all the grounds from each level (3 grounds in total) and then turn on 1 column so I get a vertical line that is lit. So I also can make a wall of LEDs just by turning on all the grounds and turning on 3 columns?
And I don't get your last sentence "I think Its possible to do all the other things you list, but you probably wont want to do them." Are you reffering to an easier way to make a 3x3x3 LED?
My name is Mike and I'am currently living in the Netherlands. This year I started my first study: electrical engineering . So I went through some things what I could do to help me with my study and came out by the 3x3x3 LED cube.
Now I do understand almost everything and I should order my parts soon. This is my parts list: -3 2N3904 NPN to use as ground switch (40V/200mA) -3 22kOhms resistor for the NPN transistors. -27 green LED's (2.2V/20mA) -I calculated with this program: http://led.linear1.org/1led.wiz , that I needed 9*150ohms resistors. Though on the internet I found that most people uses ~220Ohms resistors. I'm not sure why they do that, so if anyone can tell me I would be thankful ! -Perfboard, wires, etc -Arduino Uno rev1.
But I got a couple questions about what I can lit and what I can't: -How many LED's can I lit up at the same time? -Is it possible to lit LEDs on two different levels by grounding 2 or 3 levels at the same time and then let a current flow through a column? (So you can get a corner of 3 LEDs lit up the same time, without switching on high frequencies) -Is it possible to turn on all 9 LEDS at the same time on 1 level?