This is the first step in designing, prototyping and building a home automation system based on available hardware and some home made software. This step involves sensing some data and sending it to a remote server that does something useful with the data.
A rough sketch with the component looks like this and will be expanded in the future when new ideas pop up. Continue reading Home automation step 1
At the thrift shop I found a simple LCD screen with a serial connector, yes the good old RS-232 connector.
After some searching on the web I found the controller is a BE9324MT and the display is 4 row with 16 characters. The manufacturer of the controller still has some old manuals available for reference so that became very handy. Connecting the device to a 5v power and the computer is so easy I won’t describe it.
The interface is a simple serial connector and from Linux it is easy to communicate with the display. The following piece of bash script will send the text to the screen.
echo -n "test" > /dev/ttyS0
The controller of the display just shows the message on the screen. The -n argument tells echo not the print a newline character.
From python communicating with the display is as simple as from Linux. The serial module is default included within Python.
ser = serial.Serial(0)
ser.write("x1B&#") # Escape sequence to clear the screen
ser.write("Testing the system x7E")
And this is the result of running the python code:
With xNN special characters can be shown on the device. This is the hexadecimal code that can be looked up in the manual for the display driver.
It is a nice little gadget for only € 1,50 and it works very well. Now trying to find a purpose for it.