which arduino to buy

Hi guys

i am doing a project on traffic automisation. the concept i want to use is to give time delays for LEDs based
on the traffic density.
I am new to arduino.
so pls help me with this.

which arduino model should i buy??
how many LEDs can i control individually with arduino based on input from an external sensor??

pranoy:
Hi guys

i am doing a project on traffic automisation. the concept i want to use is to give time delays for LEDs based
on the traffic density.
I am new to arduino.
so pls help me with this.

which arduino model should i buy??
how many LEDs can i control individually with arduino based on input from an external sensor??

I always suggest starting off with the basic Uno board. It has a total of 19 I/O pins available, but there are easy ways to expand to more input and output pins using simple external components. If you know for sure you are going to need more I/O pins then the Uno has then the mega board has many more built in.

Lefty

Uno.
20 IO lines, use them as needed: 2 for serial for debugging, 3 for input, 15 for output, etc.
Pick up one here on sale even.
http://www.nkcelectronics.com/Arduino_c_9.html

20 IO: D0-D13, A0-A5 which are also usable as D14-D19. 20 total.

thanks

Can the PWM pins be used for giving output??

pranoy:
thanks

Can the PWM pins be used for giving output??

The PWM pins can be used as simple digital input pins, simple digital output pins, or as pwm output pins using the analogWrite() command.

Lefty

Ok

So how do i use the analog pins as digital outputs?

pranoy:
Ok

So how do i use the analog pins as digital outputs?

With the same commands you use with any of the other digital pins, using digitalWrite() (after setting to output mode using the pinMode() command), just using pin numbers 14 to 20 that correspond to analog inputs pins 0-5.

Lefty

A0-A5 which are also usable as D14-D19.

I like some of the 3rd party "duino" boards.
For example:
http://imall.iteadstudio.com/im120905006.html
There is also an iteaduino which is a bit less that uses the FTDI chip vs the atmel processor
for USB to serial conversion.
http://imall.iteadstudio.com/development-platform/arduino/arduino-compatible-mainboard/im120411008.html

Will work just the same as an UNO, but there are some nice extra features
like the 3 pin headers that allow hooking up things like 3 pin sensors or servos
directly to the board
as well as an option to run 3v.

--- bill