Display, buttons, LEDs

Yozh contains a buzzer, two NeoPixel LEDs in the back and an 128x64 OLED screen and two buttons on the top plate, for interaction with the user. To control them, use the functions below.

LEDs

set_led_L(color)
set_led_R(color)

These commands set the left (respectively, right) LED to given color. Color must be a list of 3 numbers, showing the values of Red, Green, and Blue colors, each ranging between 0–255, e.g. bot.set_led_L([255,0,0]) to set the left LED red. You can also define named colors for easier use, e.g.

BLUE=[0,0,255]

bot.set_led_L(BLUE)
set_leds(color_l, color_r)

Set colors of both LEDs at the same time. As before, each color is a list of three values. Parameter color_r is optional; if omitted, both LEDs will be set to the same color.

set_led_brightness(value)

Set the maximal brightness of both LEDs to a given value (ranging 0-255). Default value is 64 (i.e., 1/4 of maximal brightness), and it is more than adequate for most purposes, so there is rarely a need to change it. Setting brightness to 255 would produce light bright enough to hurt your eyes (and drain the batteries rather quickly)

Buzzer

buzz(freq, dur=0.5)

Buzz at given frequency (in hertz) for given duration (in seconds). Second parameter is optional; if omitted, duration of 0.5 seconds is used.

Buttons

wait_for(button)

Waits until the user presses the given button. There are two possible pre-defined buttons: bot.button_A and bot.button_B

is_pressed(button)

Returns True if given button is currently pressed and False otherwise.

choose_button()

Waits until the user presses one of the two buttons. This function returns string literal A or B depending on the pressed button:

bot.set_text("Press any button", line1)
#wait until user presses one of buttons
if (bot.choose_button()=="A"):
    # do something
else:
    # button B was pressed
    # do something else

OLED

The easiest way to interact with OLED display is by using the commands below.

clear_display()

Clears all text and graphics from display

add_textbox()

Add textbox (also known as label) to display. You can enter the actual text when creating the textbox, or replace it later. The command returns index of the textbox, which can be used to update the contents of the textbox later.

The basic use of this command is

line1 = bot.add_textbox(text_position=(0,10), text="Yozh is happy!")

The command accepts a number of optional parameters, documented below.

add_textbox()
Parameters

  • text_font – The path to your font file for your data text display.

  • text_position – The position of text on the display in an (x, y) tuple.

  • text_wrap – When non-zero, the maximum number of characters on each line before text is wrapped. (for long text data chunks). Defaults to 0, no wrapping.

  • text_maxlen – The max length of the text. If non-zero, it will be truncated to this length. Defaults to 0, no truncation.

  • text_scale – The factor to scale the default size of the text by

  • line_spacing (float) – The factor to space the lines apart

  • text_anchor_point ((float, float)) – Values between 0 and 1 to indicate where the text position is relative to the label

  • text – If this is provided, it will set the initial text of the textbox.

set_text(text, i)

Replaces text in textbox with index i, e.g.

line1 = bot.add_textbox(text_position=(0,10), text="Yozh is happy!")
time.sleep(1.0)
bot.set_text("Press any button", line1)

Writing empty text into a textbox deletes it. Thus, if you want to erase current text but keep the textbox for future use, replace the text with a single space bot.set_text(" ", i)

Advanced users may also use any commands from CircuitPython displayio module to put text and graphics on the OLED display as described in https://learn.adafruit.com/circuitpython-display-support-using-displayio. The display object of the robot can be accessed as bot.display, e.g.

 display = bot.display
 # Setup the file as the bitmap data source
 bitmap = displayio.OnDiskBitmap("/purple.bmp")

# Create a TileGrid to hold the bitmap
tile_grid = displayio.TileGrid(bitmap, pixel_shader=bitmap.pixel_shader)

# Create a Group to hold the TileGrid
group = displayio.Group()

# Add the TileGrid to the Group
group.append(tile_grid)

# Add the Group to the Display
display.show(group)