Arduino rs232 communication question from a complete newbie.

Hello all

Beeing totally new with arduino I want to se if I can get a barometer up and running.
I understand that the arduino has a serial port thru the USB port.

The question is, can I Program the arduino from the pc thru the USB port, disconnect the arduino and let it run standalone, and then somehow access the serial so i can read data from the barometer attached to some og the other pins? The barometer is a module Made to interface with arduino.

I have seen some ttl to serial adapers, maybe I need one og those?

Regards
TommyE

TommyE:
Hello all

Beeing totally new with arduino I want to se if I can get a barometer up and running.
I understand that the arduino has a serial port thru the USB port.

Yes the ardunio's AVR chip has an internal serial port and it is wire to a USB converter chip to allow serial data to and from a PC for uploading new sketches and can be used for general purpose serial communications between the arduino board the a PC with proper PC application program running, such as a terminal program.

The question is, can I Program the arduino from the pc thru the USB port, disconnect the arduino and let it run standalone, and then somehow access the serial so i can read data from the barometer attached to some og the other pins? The barometer is a module Made to interface with arduino.

Yes you can. If the arduino USB is not plugged into a PC, then you are free to use the chips serial port by wiring the receive and send TTL level serial data to shield pins 0 and 1.

I have seen some ttl to serial adapers, maybe I need one og those?

If your barometer uses TTL voltage level serial voltages then you need nothing else to wire it to arduino serial pins 0 and 1. If however is uses true RS-232 serial voltages then you do require something to convert from RS-232 serial voltages to TTL serial voltages. Check you barometer's datasheet, or post a link to it here and let us see if we can determine what you need if anything.
Good luck.
Lefty

Regards
TommyE

retrolefty:

TommyE:
Hello all

Beeing totally new with arduino I want to se if I can get a barometer up and running.
I understand that the arduino has a serial port thru the USB port.

Yes the ardunio's AVR chip has an internal serial port and it is wire to a USB converter chip to allow serial data to and from a PC for uploading new sketches and can be used for general purpose serial communications between the arduino board the a PC with proper PC application program running, such as a terminal program.

The question is, can I Program the arduino from the pc thru the USB port, disconnect the arduino and let it run standalone, and then somehow access the serial so i can read data from the barometer attached to some og the other pins? The barometer is a module Made to interface with arduino.

Yes you can. If the arduino USB is not plugged into a PC, then you are free to use the chips serial port by wiring the receive and send TTL level serial data to shield pins 0 and 1.

I have seen some ttl to serial adapers, maybe I need one og those?

If your barometer uses TTL voltage level serial voltages then you need nothing else to wire it to arduino serial pins 0 and 1. If however is uses true RS-232 serial voltages then you do require something to convert from RS-232 serial voltages to TTL serial voltages. Check you barometer's datasheet, or post a link to it here and let us see if we can determine what you need if anything.
Good luck.
Lefty

Regards
TommyE

Lefty, thanks for your answers.

I really appreciate them.

Just to ellaborate on my first post, here is a 'drawing' (if it can be called that :slight_smile: ) That shows how I hope the final connections can be made.
Please note that the pins on the arudino is random.

Can it be done this way?

Regards
Tommy

Can it be done this way?

No. The Arduino can not communicate with other devices using the USB port. It can communicate with devices that are TTL level, if those devices are connected to TX and RX (and ground, of course). The left side of your picture won't work. The right side will, if you also connect ground (and power).