Bottle filling station

Parts in this circuit

Wiring, pin by pin

Red = 5 V, orange = 3.3 V, black = GND, other colours = signals. “Pin” is the position on the 40-pin header; the GPIO number is what the code uses. Power the Pi from a 5.1 V supply and wire with the power off.

Python code (gpiozero)

from gpiozero import Button, OutputDevice, LEDBarGraph, Buzzer
from time import sleep

bottle = Button(17)                           # beam broken = bottle in place
pump = OutputDevice(22, active_high=False)
box = LEDBarGraph(5, 6, 13, 19, 26)
horn = Buzzer(18)

FILL_TIME = 3
BOX_SIZE = 5
filled = 0

print("Click the beam sensor to place a bottle")
while True:
    bottle.wait_for_press()
    print("Bottle detected: filling")
    pump.on()
    sleep(FILL_TIME)
    pump.off()
    filled += 1
    in_box = filled % BOX_SIZE
    print("Bottle", filled, "filled")
    if in_box == 0:
        box.value = 1
        horn.beep(0.2, 0.1, n=3)
        print("BOX FULL: replace the box")
        sleep(2)
        box.value = 0
    else:
        box.value = in_box / BOX_SIZE

How the code works

• The beam sensor is a Button: broken beam means pressed.
• The pump runs for FILL_TIME seconds. Nothing else is read while it runs, so a second bottle cannot start a second fill.
• The remainder (filled % BOX_SIZE) tells how many bottles are in the current box.

Parts to buy

The links open a search on each store, so you see what is in stock today. Check the model, voltage and price before you order.