Battery voltage

What this example shows

Read the voltage of the Li-ion battery on the JST connector once and print it on the screen. Connect a battery for a meaningful reading.

Example code

"""Read the battery voltage."""

# Include needed libraries
from inkplate7spectra import Inkplate

# Creates an Inkplate object
inkplate = Inkplate()

# Initialize the display, needs to be called only once
inkplate.begin()

# Get the battery reading as a string
battery = str(inkplate.read_battery())

# Set text size to double from the original size, so we can see the text better
inkplate.set_text_size(2)

# Print the text at coordinates 100,100 (from the upper left corner)
inkplate.print_text(100, 100, "Battery voltage: " + battery + "V")

# Show it on the display
inkplate.display()

Functions used

Inkplate()returns Inkplate

Creates the display object from the inkplate7spectra module.

ReturnsThe display object.

inkplate.begin()returns bool

Sets up the board, the battery ADC on IO1 included, and a white frame buffer. Call it once.

ReturnsTrue.

inkplate.read_battery()returns float

Switches on the battery measurement divider with GPIO expander pin P1-1, reads the ADC on IO1, switches the divider off and converts the reading to volts.

ReturnsBattery voltage in volts.

inkplate.set_text_size(s)returns None

Sets the text scale factor, here 2.

ReturnsNothing.

inkplate.print_text(x, y, s)returns None

Draws text at (x, y) in the current size and color, without moving the cursor.

ReturnsNothing.

inkplate.display(leave_on=False)returns None

Sends the frame buffer to the panel and refreshes it.

ReturnsNothing.

What to expect

After the refresh, the screen shows Battery voltage: followed by the reading and V, in black at (100, 100). The script reads the battery once; run it again for a new reading. Nothing is printed in the shell.

🔗Open the complete example

examples/inkplate7spectra/battery_read.py

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