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Topic: Advise required to choose right arduino board (Read 1 time) previous topic - next topic

kumar_14

Hi,
     I am working on a project where I need to use 24 pins for output. Which board should I use for this purpose. Can I use mega for this purpose or should I go with uno and shift registers?

CrossRoads

Go with something in between - 1284P, with 32 IO.
I have kits ready to go.
http://www.crossroadsfencing.com/BobuinoRev17/
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

kumar_14

Dear CrossRoads,
                                Thank you for the reply. What is the difference between your board and mega? Because mega got 54 pins........ I am very new to MCU field somebody please help me to understand. I need to use 24 out put pins to control 24 servos. I understood that for powering servo i need external power. I am going to use arduino for controlling the power to servo and also I need 4 to 6 input pins. Please advise me which board should I choose ------------ uno with shift register or mega will serve?

capicoso

Nice one CrossRoads! I wasn't aware of these. I'll buy one in the future if you ship to Argentina.

I prefer CrossRoads 1284 board over the MEGA because once you finished your project, you can just take the Atmega1284 and put it in a standalone circuit, and this way, if you want to make many products, you won't have to buy a board for each finished unit. The MEGA has a SMD chip, so you can't take it, you have to sacrifice a whole board inside the unit. That's why I was sticking to Arduino UNO, because the atmega is DIP package. But now I saw CrossRoads'...

kumar_14

Hi capicoso,
                      Thank you for your suggestion. But you know I am not a electronics guy. So I have to use individual board for my each project. I cannot design a pcb and mount the components. So the best way for my project would be to go for an existing full version board for each project. Please advice how to go about with 24 pin out put..........................

Paul__B

Yes, the advice is:  Unless you believe you find a better option, go to CrossRoads' website and you can purchase the board shown from him with an entirely suitable number of interface pins.

kumar_14

Please advise me on uno or mega.............. because I cannot import the board recommended  here..........
As per this link                http://arduino.cc/en/Reference/PortManipulation
can I assign pins as out put in mega to use 24 out put pins??????????

kumar_14

Somebody please answer my question........................?

I also have this doubt.....
Once I upload sketch to the arduino board does it remember the sketch even if it is unplugged from power or every time I power the board should I upload the sketch?

MichaelMeissner

#8
Oct 30, 2013, 01:30 pm Last Edit: Oct 30, 2013, 01:33 pm by MichaelMeissner Reason: 1

Somebody please answer my question........................?

I also have this doubt.....
Once I upload sketch to the arduino board does it remember the sketch even if it is unplugged from power or every time I power the board should I upload the sketch?

The Arduino remembers the sketch.  In the normal case, when you power it on, the bootloader runs first, and spends a few seconds to see if there is new programming.  If not, it goes on to the last program that was installed.

There are other options.  You could eliminate the bootloader and only program the system with a hardware programmer.  This would give you more program memory, and the system would start immediately, but this is an advanced usage.

Normal static/global variables are reset to their initial values when the processor is restarted.  On most Arduinos and Arduino clones (except the Due, and maybe some others), you have a third type of memory (EEPROM) that is not overwritten by power up, that you can use to store defaults and summaries.  You have to use functions to read values from EEPROM and to write to it.

For example, you could first flash a program that sets EEPROM to certain values, and then flash a different program that used those values as a default so you didn't need to add dip switches, or whatever to change defaults.  You can even write small amounts of data there, and flash a 3rd program to dump it to the serial monitor, so you could use it as a battery operated data collector for a small amount of data, and then later dump it back to the mother ship.

MichaelMeissner


Please advise me on uno or mega.............. because I cannot import the board recommended  here..........
As per this link                http://arduino.cc/en/Reference/PortManipulation
can I assign pins as out put in mega to use 24 out put pins??????????

I believe on the Mega, you can use all 54 pins as digital output or digital input pins.  Even pins that can be used for analog input can be used for digital input/output.  Note, some microprocessors that support the Arduino ecosystem have some analog pins that cannot be used for digital input/output, but I don't think the Mega has pins like that.  Some pins have special uses, so you might want to avoid those (particularly the LED pin, but also the pins for USB/I2C/SPI), but you should be able use 40 without worrying about the special uses.

kumar_14

Hi MichaelMeissner ,
                                         That was awesome................ Thank you very much for your answer. I will go with mega board................... :)

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