Using Tx and Rx ports with several modules


Can I use the Tx and Rx ports with a GSM and a GPS modules at the same time?

Regards and thanks in advance.

Do you have a Mega2560? In this case: yes because this Arduino has 4 serial interfaces. Otherwise: No.

If you provide a bit more information we might give you hints how you can circumvent your problems.

Thanks Pylon!

I want to develop an application which sends a sms (GMS module) with the location obtained with a GPS module. Also, I need to store this information in a microSD.

To avoid bigger troubles plan for a Mega2560 from the beginning. Although you might get it done with UNO (or compatible) with some hassles and software emulations your live will be much easier if you have 4 hardware serial interfaces to use.

and... how about to feed the arduino mega with a car battery?


Take a look at softwareSerial!.


Hi, Here's a software serial example using both the USB Serial monitor and a Software Serial port talking to another Arduino. Not exactly what you need, but an example of setting up Software Serial:

and... how about to feed the arduino mega with a car battery?

Should be no problem. Take care if it's not the car battery but the car electrical system because there you might get voltage spikes that may hurt the Arduino.

to run an arduino off a car battery all you really need is to get a little barrel power connector to go to the arduino, and put the pos and neg leads on it to the battery. However it might worry me a little to have my electronics running straight off that battery like that. Personally I've installed a couple of lighter jacks under the hood, and thats what I connect my electronics to. A little more standard, looks better then random leads, and your mechanic won't give you nearly as much crap about it.

Thanks to everyone!!

I think I'm going to use this

I think I'm going to use this

Where do you want to connect it to? For Vin it's voltage is too low, I don't know if it's stable enough to drive the 5V pin directly. And in many cases it's not needed because you can connect the car battery power directly to the Arduino (power connector).

Or use one of these with USB cable to the Arduino USB port

I guess a 5V regulator on a heat sink is out of the question? Arduino has one and should be able to run off IIRC 14V through it. Maybe add an inductor to help avoid spikes ruining the regulator?

I got one of the car MP3 players that plugs in the cig lighter socket and plays through the car radio and PITA problem, car hits a bump and power is interrupted! I guess that’s what I get for buying a cheap device.

I need to connect it to a tractor, so I can't use the standard lighter socket.

Does the tractor have a fuse box?

Yes, it does

That would be the logical place to see about adding connections. At least it is in cars where you’d find an accessories fuse. Do check capacities and if needed, add a fuse somewhere and whatever power regulation after that.