Arduino mega 2560 or STM32F4-Discovery

[lmtfreak]

I'm new to microcontroller and I want to learn about it. On my local shop the Arduino mega 2560 and STM32F4-Discovery both are cost 20$. Can anyone suggest me which board should I buy to get me started?
 
Some projects I want to do with microcontroller:
Led dimming
Led Matrix
Temperature sensor
Real time clock
Turn on and off led with hand clapper
Control servo motor
LCD display
Mp3 player
Image processing
Speech recognition

[Bored@Work]

Arduino: Toy for those who want to copy, not learn.

STM32F4-Discovery: Like all similar boards: Difficult if you never worked with micro controllers before, normal stuff if you have.

[lmtfreak]

Arduino: Toy for those who want to copy, not learn.

STM32F4-Discovery: Like all similar boards: Difficult if you never worked with micro controllers before, normal stuff if you have.

Do you mean with Arduino I can easily work with my projects but not learned much, with STM32F4-Discovery hard to work but learned more about microcontroller?

[AndreasF]

If you're completely new to microcontrollers, you're probably better off with the Arduino initially. One thing you can (and should) do with it is to leave the Arduino IDE and libraries behind and do more direct low-level programming.

The Discovery board is great, but definitely a bit more complex. I would have probably been more frustrated with it than I was when I wouldn't have had some prior experience with Arduino and the TI Launchpad.

[sleemanj]

Do you mean with Arduino I can easily work with my projects but not learned much, with STM32F4-Discovery hard to work but learned more about microcontroller?

You can learn as much or as little as you like with an Arduino based board.  An Arduino is just an AVR at the end of the day, if and when you want to go "bare metal", go for it.

[Bored@Work]

Arduino: Toy for those who want to copy, not learn.

STM32F4-Discovery: Like all similar boards: Difficult if you never worked with micro controllers before, normal stuff if you have.

Do you mean with Arduino I can easily work with my projects but not learned much, with STM32F4-Discovery hard to work but learned more about microcontroller?

What I mean is the Arduino is part of a culture, if not to say the center of a cult. And that culture consists of copying code without understanding it, buying shields and telling the world how awesome someone is who copies code and buys shields.

The Discovery is a typical MCU board. You find some code and examples, but you sooner or later *gosh* have to give the datasheet of the MCU and other documentation a good look, have to study existing code, write your own and even debug it.

[AndersAnd]

On thing to take into consideration is that STM32F4 like most 32-bit MCUs won't run at 5V, it has an operating voltage of 1.7 to 3.6 V.

Most Atmel 8-bit AVRs on the other can run at 5 V too, like most other 8-bit MCUs.
This makes it easier to interface to 5V peripherals.
Standard character displays for example can typically only run at 5 V logic levels, so this makes it simpler to intrface as you don't need any level converters.

Even though you buy an Arduino mega 2560 board, you don't actually have to use Arduino at all, but can program it in assembly and/or C, which are the two programming languages used by almost all professional MCU programmers.
Atmel Studio 6 is a complete and free toolchain, where you can program Atmel AVRs (and ARMs) in both assembly and C: http://www.atmel.com/microsite/atmel_studio6/

Once you have learned to program an 8-bit MCU in C, it's not a big step to upgrade to a 32-bit MCU later, as you can still program it in C.

If you go with AVR, there's a large community dedicated to this MCU, where you can find a lot of help and ideas: http://www.avrfreaks.net

[dannyf]

Can anyone suggest me which board should I buy to get me started?

Both will do the kind of projects you want.

The avr is much easier to get started, even more so with the Arduino.

The STM32F4 is much more powerful, if you want to do more in the future.

Which one works for you will depend on how gifted you are, as an embedded programmer, and what you want to get out of this experience.

If it is for self-learning, either is fine.

If you want to make a living out of this, pick the STM32F4.

[westfw]

LCD display
Mp3 player
Image processing
Speech recognition

These are, IMO, a bit beyond what you can expect to do with the 16MHz 8-bit microcontroller that is the core of an Arduino.  They may be beyond the 100+MHz 32bit microcontroller on the STM board as well, but your chances are better.

the Arduino is part of a culture

A culture that has published multiple books and hundreds of forum messages a day, written libraries, tutorials, and examples, helping people to DO things with their Arduino.  The STM ... not so much.
You can sit there and copy code for your Arduino, and never learn anything.  Or you can sit there with your STM figuring out how to do every little bit of everything, and never get things done.   Neither extreme is a good place to be.   (And - ST will want to to use their "Standard Peripheral Library", but I'm not sure that it's better in any way than the Arduino libraries...)

YMMV.