Poop Conveyor belt

I really liked the idea of having a conveyor belt for my printer poop, but because of where I have my printer, I don’t have space for other designs I’ve seen, so I made this design. It is only 57.7 mm wide and fits perfectly beside the A1 and is no wider than the printer.

🛠️ Assembly Guide

 Join the Conveyor Housing

• Interlock the two housing halves.
• Insert the 90° elbow pieces into their side slots.
• For extra strength, secure joints with a small amount of hot glue if needed.

Bearings & Rear Shaft

• Press-fit the four printed bearings into the housing.
• Slide in the long rear shaft.
• Mount the belt drive spindle and attach the drive pulley to the outside end.

 Build the Belt

• Print 32 belt links (you’ll use 31, plus 1 spare).
• Assemble using the pins and links.
• Wrap the belt around the rear drive shaft and over the front rollers.

Frame & Front Shaft

• Pull the housing together and insert the short front shaft.
• Secure with the two end caps.

 Motor & Electronics

• Mount your stepper motor in the motor housing.
• Use the spacer plate if needed for a snug fit.
• Connect the motor to the Pico Motor Driver HAT, then stack it onto the Raspberry Pi Pico.
• Power via the Pico’s micro-USB port.

💡 Cooling Tip:
Apply a thin layer of thermal paste (or toothpaste if you don't have any) between two pennies. Use pennies made in or before 1976 as they conduct heat better being 95% copper and 5% zinc. Newer pennies are the opposite: 95% zinc and 5% copper.  
Place them flat against the hat’s main chip and hold them in place with a rubber band.
It’s a quick, inexpensive DIY heatsink that works well for light-duty use.

The code runs it for 20 seconds every 30 minutes.

======================================

from machine import Pin

import time

# LED indicator

led = Pin("LED", Pin.OUT)

# Stepper driver pins (for Pico Motor Driver HAT)

M1E = Pin(17, Pin.OUT)

M1A = Pin(21, Pin.OUT)

M1B = Pin(20, Pin.OUT)

M2E = Pin(16, Pin.OUT)

M2A = Pin(19, Pin.OUT)

M2B = Pin(18, Pin.OUT)

# Enable both driver channels

M1E.value(1)

M2E.value(1)

# 8-step half-step sequence

steps = [

    [1,0,1,0],

    [1,0,1,1],

    [0,0,1,1],

    [0,1,1,1],

    [0,1,0,1],

    [0,1,0,0],

    [1,1,0,0],

    [1,1,1,0]

]

def setStep(p1, p2, p3, p4):

    M1A.value(p1)

    M1B.value(p2)

    M2A.value(p3)

    M2B.value(p4)

# Main loop — run forward then stop

while True:

    for i in range(512):  # one rotation (for 64:1 gearbox)

        for step in steps:

            setStep(*step)

            led.toggle()

            time.sleep(0.005)  # 5 ms between steps → adjust for speed

    print("Pause 30 minutes")

    time.sleep(30*60)

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Note: this design was based on “A1 Poop Conveyor” and used some parts from it. Credit to @nigeljohnson73l.

The drive system has been completely redesigned along with new code. I also added printed bearings and designed a motor housing and pins to hold the links together.