all about pins.. help

ok, i'm seeing a lot of talk about "pins"... searching ebay amongst other places, i see a lot of differnt "pins"..

i see shift resistors with pins, 1 sing a single row of 8 pins, 40 pin break away header pins, screw pins - (usually green blocks), angle pins, 5 way header pin, etc.. i see so many different "pins" - how do you know exactly what you want? i know it depends on the project.. but still

i was once told in another topic of mine: i would need 300 I/O pins..

to me a pin is just a pin, just how many you use is the thing right?

so, if someone could kindly please explain the "pins".. i would appreciate that..

thanks

A 'pin' is a single conductor in a connector. There are as many different kinds of pins as there are things to be connected together.

On the Arduino we are usually talking ab out digital pins or analog input pins. Sometimes we talk about PWM (analog) output pins.

Without a lot more context there is not a lot more one can say about 'pins'.

I can understand your confusion, but in a different context you asked the question: "I keep hearing about 'food.' Can someone explain to me all the different kind of food and how you choose them?"

Did you mean people food? Dog food? What types you should and should not eat? What is considered food, what isn't? Etc.

See why it would be difficult to answer your question?

i was once told in another topic of mine: i would need 300 I/O pins..

in my other topic i wanted to multiplex 100 rgb leds..

Ruffsta:

i was once told in another topic of mine: i would need 300 I/O pins..

in my other topic i wanted to multiplex 100 rgb leds..

Pins inside of a shift register or microcontroller are connected to transistors that get turned on or off.

To control 100 RGB LEDs (that's 3 LEDs in 1) you would need 300 transistors. So you want enough transistors connected to pins, connected to your LEDs. This probably means chaining together (a large amount) of shift registers.

Edit: I missed the multiplex part... So you wouldn't need 300.

Ruffsta:

i was once told in another topic of mine: i would need 300 I/O pins..

in my other topic i wanted to multiplex 100 rgb leds..

If you wanted to control 100 RGB LEDs WITHOUT multiplexing then you would, indeed, need 300 digital or PWM output pins, one per LED element. If that had been the case you probably would have been advised to strign together a bunch of shift registers.

With multiplexing you can use fewer pins at the expense of brightness and possibly flicker.

Ruffsta:

i was once told in another topic of mine: i would need 300 I/O pins..

in my other topic i wanted to multiplex 100 rgb leds..

Then the answer was wrong.

The whole point of multiplexing is to use less than 300 pins.