Using the curses library to view IoT data

Curses Windows

The examples so far have been based on a main screen object, but the curses library also supports windows. Windows are useful because they support border outlines, and text can be cleared from and written to windows without affecting the main screen object. The syntax to create a curses window object is:

mynewwindow = curses.newwin(  height, width, begin_y, begin_x)

The code for Figure 3,

# define a win1 window object
win1 = curses.newwin(9, 44, 6, 4)
# write text inside the window object
win1.addstr(8,0, "Sensor 1: Temperature Reading", curses.A_BOLD)
value1 = pyfiglet.figlet_format(  "23 C", font = "doom") win1.addstr(0,0,value1,curses.color_pair(2) )
Figure 3: Large text in two curses windows.

produces two curses windows. The major difference in the code is that information within a window is addressed by the window object instead of the background screen object.

Dynamic Bars

Simple progress or indicator bars can be created by a curses window with a border (Listing 4). The bar itself is generated by writing a space character with inverse video (Figure 4).

Listing 4

01 import curses
03 bar = ' '   # with reverse video a space will show up
04 value1 = 10  # in real life this needs to be scaled
06 stdscr = curses.initscr()
07 curses.curs_set(0) # don't show the cursor
09 stdscr.addstr(1,3, "Python Curses Bar")
10 stdscr.refresh()
11 # Define windows
12 win1 = curses.newwin(3, 32, 3, 2)
13 win1.border(0)  # add a border
14 # a horizontal bar 10 characters wide
15 win1.addstr(1, 1, bar * value1,curses.A_REVERSE )
16 win1.refresh()
18 # Wait for a key press then exit
19 stdscr.getch()
20 curses.endwin() # restore the terminal to original settings
Figure 4: A simple curses bar.

After I had the basic curses bar working, I was able to use what I learned in the earlier examples to create Raspberry Pi interfaces that included color and large text (Figure 5).

Figure 5: Raspberry Pi sensor data presented as bars.


If you are looking for a quick and easy way to present data, without the bother of a GUI, curses is a great solution. Curses is supported in a variety of programming languages. I focused my curses work here on C and Python, but I've also had good success in Lua.

I only had one presentation issue and that was with line drawing characters like borders when I used Putty (a Windows-based SSH program). To fix this issue, I changed the Putty Window | Translation setting to use the VSCII character set; then, everything looked good.

The Author

You can investigate more neat projects by Pete Metcalfe and his daughters at

Buy this article as PDF

Express-Checkout as PDF
Price $2.95
(incl. VAT)

Buy Linux Magazine

Get it on Google Play

US / Canada

Get it on Google Play

UK / Australia

Related content

  • Nerf Target Game

    A cool Nerf gun game for a neighborhood party provides a lesson in Python coding with multiple processors.

  • Perl: Internet Video Organizer

    Video files are ready for download, but your storage space is limited, and, if you're like most people, you may have a hard time letting go of past favorites. You need a higher authority to decide when it’s time to trim down your collection.

  • Serial Communications

    We explore serial communications, from the electrical specs to protocols and libraries, with an example of serial communication with an Arduino.

  • Perl: Dynamic netstat

    The netstat utility reveals how your Linux box interacts with the local network. With a few Perl modules, you can develop a tool that displays the data dynamically, exactly the way top does.

  • BPython 0.9.6: Python Command Line at Ease

    BPython is an interactive Python command line interface with its own comfort functions. The program is now available in version 0.9.6.

comments powered by Disqus
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters

Support Our Work

Linux Magazine content is made possible with support from readers like you. Please consider contributing when you've found an article to be beneficial.