Display problems

Non-ASCII characters can’t be displayed

When running the SimulRPi.run_examples script or using the SimulRPi.GPIO module in your own code, your terminal might have difficulties printing the default LED symbols based on special characters:

UnicodeEncodeError: 'ascii' codec can't encode character '\U0001f6d1' in position 2: ordinal not in range(128)

This is mainly a problem with your locale settings used by your terminal.

Solution #1: change your locale settings (best solution)

The best solution consists in fixing your locale settings since it is permanent and you don’t have to change any Python code.

  1. Append ~/.bashrc or ~/.bash_profile with:

    export LANG="en_US.UTF-8"
    export LANGUAGE="en_US:en"

    You should provide your own UTF-8 based locale settings. The example uses the English (US) locale with the encoding UTF-8. The locale -a command gives you all the available locales on your Linux or Unix-like system.

  2. Reload the .bashrc:

    $ source .bashrc

3. Run the locale command to make sure that your locale settings were set correctly:

$ locale

  1. Run the SimulRPi.run_examples script to test if you can display the LED symbols fine using the correct encoding UTF-8:

    $ run_examples -s -e 1


    Terminal output: set locale settings correctly

See also

Solution #2: export PYTHONIOENCODING=utf8 (temporary solution)

Before running the SimulRPi.run_examples script, export the environment variable PYTHONIOENCODING with the correct encoding:

$ run_examples -s -e 1


Terminal output: export PYTHONIOENCODING=utf8

However, this is not a permanent solution because if you use another terminal, you will have to export PYTHONIOENCODING again before running the script.

Use ASCII-based LED symbols

If you tried the previous two solutions, and you still can’t display the LED symbols that use special characters (UTF-8 encoding), you can instead opt for ASCII-based LED symbols.

Method #1: use the SimulRPi.GPIO API

If you are using the SimulRPi.GPIO module in your code, you can change the default LED symbols used by all output channels with the function setdefaultsymbols(). Hence, you can provide your own ASCII-based LED symbols using ANSI codes to color them:

Example: updating the default LED symbols with ASCII characters and ANSI codes
   import time
   import SimulRPi.GPIO as GPIO

          'ON': '\033[91m(0)\033[0m',
          'OFF': '(0)'
   led_channel = 11
   GPIO.setup(led_channel, GPIO.OUT)
   GPIO.output(led_channel, GPIO.HIGH)

Or you can provide the argument "default_ascii" to the function setdefaultsymbols() which will provide default ASCII-based LED symbols for you:



Terminal output: ASCII characters used for LED symbols


If working with the Darth-Vader-RPi library, you can use ASCII LED symbols when running the start_dv script by assigning the value “default_ascii” to the default_led_symbols setting in the main configuration file:

"default_led_symbols": "default_ascii",

See also

Method #2: use the command-line option -a

When running the SimulRPi.run_examples script, you can use the command-line option -a which will make use of ASCII-based LED symbols:

$ run_examples -s -e -1 -a


Terminal output: ASCII characters used for LED symbols

Multiple lines of LED symbols

When running the SimulRPi.run_examples script, if you get the following:

Bad display when running the script in a small terminal window

It means that you are running the script within a too small terminal window, less than the length of a displayed line.

Solution: enlarge the window

The solution is to simply enlarge your terminal window a little bit:

Good display when running the script in a larger terminal window

Technical explanation: the script is supposed to display the LEDs turning ON and OFF always on the same line. That is, when a line of LEDs is displayed, the script goes to the beginning of the line to display the next state of LEDs by printing over the previous LEDs.

However, when the window is too small, the first line of LEDs that gets printed overflows on the second line since there is not enough space to print everything on the first line. Then, the script won’t be able to overwrite the first line of LEDs because it will be positioned on the second line instead. So you get this display of multiple lines of LEDs.