Arduino Wireless Internet Interface Configuration to Control via RS232

im pretty new in this themes.
I want to set up an arduino to control a componenten via RS232.
The control should work with a wireless connection to set some parameters to generate the output for the RS232.
In the last step i would like to visualize the input of some sensors (0-8V) on the wireless conected device.

Can you give me some hints how to get started and which components are necessary to get this done?

Thank you so much :slight_smile:

If you are new to the Arduino system I suggest you get an Uno and work through several of the examples that come with the Arduino IDE.

Your description of what you want to do is not sufficiently detailed to give you specific advice - what is the RS232 device? what sensors? what sort of wireless?

You should view the project as several separate pieces and learn how do each one on its own before you try to combine them.


the wireless connection should be W-Lan
The RS232 device is just a "box" which need input via a RS232 connection
The input for the RS232 connection depends on a few parameters, which should be communicated via W-Lan (HTML or JacaScript?) to the arduino device.
About the sensor im not quit sure, thats just a generell question if it is possible to visuallize sensor input data with W-Lan (JavaScript?)

is it generell possibile to get this szenario done?

no way to get an answer?

is it generell possibile to get this szenario done?

Yes, of course it is possible. Go for it.

Maybe you should go back to your first post, click modify and edit the title. It is not obvious from the present title that you need help with an wireless internet interface (WIFI ?).

I am reasonably familiar with serial comms but I don't have any WiFi stuff for my Arduinos.

If you have a specific serial comms question I will try to help.


you are great ! :slight_smile:

i looked around and found the arduino yun. it seems that this could fit to the WLan configurability and realtime sensor visualization.

the sensors have an output of 10V. Do I only need a potential divider (2 resistors, one connected to ground) to scale it? Or did i missed something?

I didnt find a RS232 shild for this arduino yun yet. the rs232 connection is essential to control my drive. do you have a hint for me for solving that problem? Or is it possible to connect a USB-to-RS232 cable to creat "real" RS232 output?

thanks so much in advance :))

You must use voltage dividers to ensure that the maximum voltage on an I/O pin is 5v.

The Atmega side of the Yun has a serial connection which can be used to communicate directly with an RS232 device. The only thing to watch for is that "proper" RS232 uses 12v whereas the Yun (and other Arduinos) uses 5v. You can get a chip such as a MAX232 (I think) to convert the voltages between the two systems. Once you have the voltages sorted out communication with an RS232 device should be easy.

If you are content with the "out of the box" Linux features on the Yun it should be fine. But I get the impression from the Yun section of the Forum that it may not be capable of everything a Linux expert might expect.


Do you think i should use another arduino? any suggestions which one?

I found the following RS232 Shield ( RS232 Shield - DEV-11958 - SparkFun Electronics ) with the max232 chip on it. With a shield like that it should work, right? Or will i get trouble with connecting the shield?

I have no idea if that shield would work with a Yun.

From a quick read it uses the same Rx and Tx as the Serial port on an Uno which means that it probably does not work with Software Serial so you can use the Serial Monitor and the RS232 port at the same time. I would consider being able to use them at the same time essential - especially if you are new to programming the Arduino.

I think it should be very easy to wire up a Max232 chip without needing a shield.

Are you sure that the thing you refer to as RS232 actually does need voltage conversion?


im not sureโ€ฆ
i found in the detailed description of the drive:

RS232 Interface signal levels
Please note that the signal levels are 0 to +5V(3.3V)DC and are thus not according to
the RS232 standard which requires +/-12V nominal at the RX and TX signals. However
the protocol used is equivalent to the RS232 protocol.

If the drive and the arduino work with a 5V RS232 connection i shouldnt need a Max-Chip, right?
So i need to wire my own arduino to rs232 connection?

Some simple TTL/rs232 setups.

If the drive and the arduino work with a 5V RS232 connection i shouldnt need a Max-Chip, right?
So i need to wire my own arduino to rs232 connection?

Connect Rx to Tx, Tx to Rx and GND to GND.

It is probably more correct to call a 5v system Serial TTL rather than RS232.