which board and shields?

Projects General Guidance
1

hello

I got several industrial devices in the hand, they are mainly logger devices. these devices have both analog and rs232 output.

Now , i need to connect several of these devices to an arduino board and get their readings separately and pack them to an internet server.

at this very point , which board and shields required to do this job in a pain-free way?

thanks

2

A computer (server) can communicate with an Arduino via the USB cable; it will register itself as a serial device. See Arduino Playground - InterfacingWithSoftware

If your Arduino is not in proximity to a computer on your network and must connect via ethernet, then a shield based on the Wiznet W5100 would be recommended.

A device with an RS232 output (+/- 12V signals) must have its signals brought down to 0-5V to connect to the Arduino. You will need a RS232 to TTL converter for each device with an RS232 output.

3

You did not mention how many analog devices you need to add. Different Arduino compatible processors have different amounts of analog pins, so you might want to consider looking at the spec sheets to see if there are enough ports:

  • The Uno R3 has 6 analog inputs, of which 2 are used for I2C;
  • The Leonardo has 12 analog inputs, so 6 of the analog inputs overlap with digital pins;
  • The Mega and the Due have 16 analog inputs;
  • The Teensy 3.0 (from pjrc.com) has 12 analog inputs.

Note, the Due and the Teensy 3.0 use the ARM processor and run at 3.3v. The other processors run at 5v. You need to make sure that your analog sensors are compatible with 3.3v or 5v depending on the processor. If the sensor is 3.3v and you are using a 5v processor, or vice versa, you can use level shifters to convert the current. If not, you will need to figure out how to read the sensor and not fry either the sensor or your microprocessor.

Since you mentioned multiple serial ports, in addition to protecting the voltages, you probably want the boards that have hardware serial support (the software serial support does not support having more than one input). The Mega and Due have 4 serial ports (though you might not be able to use Serial0 and the USB serial monitor at the same time). The Teensy 3.0 has 3 serial ports (though Serial1 might not be usable with the USB monitor). The Uno and Leonardo have just one serial port.

So, I suspect the Mega is probably the board you want to use.

4

alright i see your points...

I need to connect up to 5 devices at the same time, in this case arduino uno appears sufficient for this job(assuming that i will use analog pins).

Transferring the data to an internet server have to be over gprs, because there is no other kind of internet connection available, so i simply assume that i also need a gsm/gprs shield.

well uhhm another thing is neither of you suggested rs232 shield with rs232 splitter, as well as sensor shield from emartee;

won't they fit our situation?

thanks.

5

If I'm reading it right, that shield only provides a breakout for pins 0/1 to be used in a serial connection. If you need more than 2 serial connections (using pins 0/1 that normally go to the USB for 1 connection, and software serial for the 2nd), you probably need to go straight to the Mega (or Due/Teensy 3.0). If you need more than 4 serial connections, you probably need additional hardware.