Tag Archives: home automation

Home automation step 1

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

LCD Display from the thrift shop

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.

import serial

ser = serial.Serial(0)
ser.write("x1B&#") # Escape sequence to clear the screen
ser.write("Testing the system x7E")
ser.close()

And this is the result of running the python code:
LCD Display
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.