Tutorial – communication with RS232

Communication protocol : RS232.

Communication speed : 9600 bauds

Configuration : 8 bits, no parity,  1 stop bit

1.  Connect board v2 to Raspberry

The 4 pins connector on the black cable must link the v1 board from the filtering case to the electronic board v2.

The RS232 connection from the board v2 is direct,

we are suggesting two methods to set the communication between the board v2 and the Raspberry.

First method : GPIO

This way will use the Raspberry Pi GPIO port :

NOTICE : In the current Raspberry design, it is not possible to use the UART and the Bluetooth at the same time.

It is necessary to disable the Bluetooth. If you need Bluetooth we advise you to use the second method.

Second method : converter RS232/USB

This method will be based on a converter RS232/USB (USB to UART bridge) (follow the industry-standard FTDI TTL cable interface).

It can be connected to a USB port on Rpi or on a PC.

Available on Amazon, eBay, RS-components….

Example: UM232R, LC234X…

Find it here

For this tutorial, we will use this method with the

Converter LC234X :

2.  Configure the electronic board v2 :

To enable the serial link between the Raspberry and the electronic board v2 you must enable the option Rs232 in the menu Options v2.

All commands from the Rs232 can be sent while you are navigating in the v2 menu but the information feedback in the screen console ‘step 3.4) can only be done when the v2 interface is set on the main screen.

Now your v2 is ready you can turn on your Raspberry Pi, when you are the desktop proceed the following steps :

3.1 – Launch a terminal on the raspberry :

3.2 – Update the repositories :

pi@raspberry:-$ sudo apt-get update

update the packages :

            pi@raspberry:-$ sudo apt-get upgrade

Install screen in a terminal :

            pi@raspberry:-$ sudo apt-get install screen 

3.3 – Find the connection port needed (ttyUSB0 mostly)

in the folder /dev/

pi@raspberry:-$ cd /dev && ls -lh 

3.4 –  Start screen in a terminal indicating port and port speed

            pi@raspberry:-$ screen /dev/name_of_your_port 9600

Screen console will show up :

You should receive feedback from the v2( values just for example ) :

>>> #command:value#     0.50%    3h    3000rpm     50.0%    15min    29°C

Last command | filter saturation in % | filter saturation in hours | fan speed | PWM | Timer | Temperature

if nothing is displayed on the console that means you are not on the main screen in the v2 board. You can also check if the communication with the v2 is working by pressing semicolon “;” it should return a response in the screen console.

It is important to close screen console properly : you should press ctrl+a then \ then validate with y  (it is important to free the USB port ttyUSB0)

4. Commands list :

All commands must be approved by a “;” (not enter key)

pour all commands with an attached value, they must be separated  by a “:”

4.1 –  To send a command in screen, you just need to write “command_name;”  :

In a screen console, you will not see what you are typing but for each command, you will get a response in the console :

It is important to close screen console properly : you should press ctrl+a then \ then validate with y 

Fin the commands list below:

Example of commands :

For the timer commands you can write timer:xxH; or timer:xxh, “h” in capital or lower-case.

Feel free to share your ideas and your comments to improve our solutions