3.1.5 Battery Indicator

Introduction

In this project, we will make a battery indicator device that can visually display the battery level on the LED Bargraph.

Required Components

In this project, we need the following components.

Schematic Diagram

T-Board Name	physical	wiringPi	BCM
GPIO17	Pin 11	0	17
GPIO18	Pin 12	1	18
GPIO27	Pin 13	2	27
GPIO25	Pin 22	6	25
GPIO12	Pin 32	26	12
GPIO16	Pin 36	27	16
GPIO20	Pin 38	28	20
GPIO21	Pin 40	29	21
GPIO5	Pin 29	21	5
GPIO6	Pin 31	22	6
GPIO13	Pin 33	23	13
GPIO19	Pin 35	24	19
GPIO26	Pin 37	25	26

Experimental Procedures

Step 1: Build the circuit.

Step 2: Go to the folder of the code.

cd ~/raphael-kit/python-pi5

Step 3: Run the executable file.

sudo python3 3.1.5_BatteryIndicator_zero.py

After the program runs, give the 3rd pin of ADC0834 and the GND a lead-out wire separately and then lead them to the two poles of a battery separately. You can see the corresponding LED on the LED Bargraph is lit up to display the power level (measuring range: 0-5V).

Code

Note

You can Modify/Reset/Copy/Run/Stop the code below. But before that, you need to go to source code path like raphael-kit/python-pi5. After modifying the code, you can run it directly to see the effect.

#!/usr/bin/env python3
from gpiozero import LED
import ADC0834
import time

# List of GPIO pins to which LEDs are connected
ledPins = [25, 12, 16, 20, 21, 5, 6, 13, 19, 26]
# Initialize LED objects for each pin in the list
leds = [LED(pin) for pin in ledPins]

# Setup ADC0834 module
ADC0834.setup()

def LedBarGraph(value):
    # Turn off all LEDs
    for i in range(10):
        leds[i].off()
    # Turn on LEDs up to the specified value
    for i in range(value):
        leds[i].on()

try:
    # Main loop to continuously update LED bar graph
    while True:
        # Read analog value from ADC0834
        analogVal = ADC0834.getResult()
        # Convert analog value to LED bar graph level
        LedBarGraph(int(analogVal/25))
except KeyboardInterrupt:
    # Turn off all LEDs when program is interrupted
    for i in range(10):
        leds[i].off()

Code Explanation

1. This section imports the necessary libraries. gpiozero is for controlling the LEDs, ADC0834 for interfacing with the ADC module, and time for time-related operations.

   #!/usr/bin/env python3
   from gpiozero import LED
   import ADC0834
   import time
   

2. Defines the GPIO pins to which the LEDs are connected and initializes an array of LED objects for each pin. This allows for easy control of each LED in the array.

   # List of GPIO pins to which LEDs are connected
   ledPins = [25, 12, 16, 20, 21, 5, 6, 13, 19, 26]
   # Initialize LED objects for each pin in the list
   leds = [LED(pin) for pin in ledPins]
   

3. Initializes the ADC0834 module for analog-to-digital conversion.

   # Setup ADC0834 module
   ADC0834.setup()
   

4. This function turns off all LEDs and then turns on a number of LEDs based on the input value, effectively creating a bar graph representation.

   def LedBarGraph(value):
       # Turn off all LEDs
       for i in range(10):
           leds[i].off()
       # Turn on LEDs up to the specified value
       for i in range(value):
           leds[i].on()
   

5. Continuously reads the analog value from the ADC0834 and updates the LED bar graph based on this value. The analog value is scaled down to a range of 0-10 for the 10 LEDs.

   try:
       # Main loop to continuously update LED bar graph
       while True:
           # Read analog value from ADC0834
           analogVal = ADC0834.getResult()
           # Convert analog value to LED bar graph level
           LedBarGraph(int(analogVal/25))
   

6. Ensures all LEDs are turned off when the program is interrupted (e.g., by pressing Ctrl+C).

   except KeyboardInterrupt:
       # Turn off all LEDs when program is interrupted
       for i in range(10):
           leds[i].off()