19. Final project requirements¶
Assignment (week 19):
Document a final project masterpiece that integrates the range of units covered, answering:
- What does it do?
- Who's done what beforehand?
- What did you design?
- What materials and components were used?
- Where did they come from?
- How much did they cost?
- What parts and systems were made?
- What processes were used?
- What questions were answered?
- What worked? What didn't?
- How was it evaluated?
- What are the implications?
Prepare a summary slide and a one minute video showing its conception, construction, and operation
Your project should incorporate 2D and 3D design, additive and subtractive fabrication processes, electronics design and production, embedded microcontroller design, interfacing, and programming, system integration and packaging Where possible, you should make rather than buy the parts of your project
Projects can be separate or joint, but need to show individual mastery of the skills, and be independently operable
Present your final project, weekly and group assignments, and documentation
Answering:¶
- What does it do?¶
My final project is a Smart Cat Toilet that uses Eco-friendly Wood Litter instead of commercial chemical litter. This machine is used as a toilet for pets. The machine will change litter and separate pee from litter automatically. I will use wood pellet technology which has been widely used as biomass, and try to use it as an absorber as pet litter.
- Who’s done what beforehand?¶
There are several similar products from commercial manufacturers of automatic toilet paint. This commercial product uses litter in the form of chemical sand to place the cat’s pee. While in my project I will use wood pellets (which have different sizes) which will also function as an odor absorber and cat urine which environmentally friendly.
- What did you design?¶
I designed a toilet for pets that has an automatic litter change mechanism which also provides a play area for pets. There are several steps/process to be design:
- the box house using CAD Fusion 360 and CAM Cut 2D Pro
- the drums as toilet room using CAD Fusion 360
- a mechanism for changing litter and separate the feces
- electronics system for sensors and motion for automatic change using KiCAD for the PCB design
- What materials and components were used?¶
Materials used for this equipment:
- 18mm thick plywood = 4 sheets
- MDF wood thickness 5mm, size 30mm x 50mm = 4 sheets
- High Pressure Laminates (HPL) for coating drums
- Sensors (Input devices): IR Proximity, Ammonia Sensor (MQ-137), Temperature and Humidity sensor (DHT11)
- Output Devices : Stepper Motor Nema 32, RGB Led, Buzzer
- Electronic Components: PCB board, ATtiny-3216, Resistors, Leds, Capacitors, Connectors, Cable
- Bearings
- Wood Pellet
- Acrylic 3mm
- Where did they come from?¶
Most of the material is obtained from the local market. There are some materials that are not available in the local market but sent from Fablab Kamakura
- How much did they cost?¶
| Qty | Description | Price | Link | Notes |
|---|---|---|---|---|
| 4 | Plywood 18mm | 18.20 $ | Local market | |
| 1 | MCU: Attiny 3216 | 9.60 $ | Digikey | |
| 1 | Ammonia sensor MQ-137 | 22.00 $ | Amazon | |
| 1 | High torque Nema 23 stepper | 39.99 $ | Amazon | |
| 1 | Temperatur & Humidity sensor DHT-11 | 9.99 $ | Amazon | |
| 1 | LED | 6.99 $ | Amazon | |
| 1 | RGB Led | 7.98 $ | Amazon | |
| 1 | Power supply 24v 20A | 44.99 $ | Amazon | |
| 1 | PCB Board FR-1 | 1.03 $ | Local Market | |
| 1 | Rotating Turntable Bearing | 22.99 $ | Amazon | |
| 1 | TB6600 Stepper Motor Driver | 15.99 $ | Amazon | |
| 1 | IR Proximity Switch | 12.99 $ | Amazon | |
| 1 | Buzzer Active | 6.98 $ | Amazon | |
| 1 | Acrylic 12 in x 24 in | 35.95 $ | Amazon | |
| 1 | JST-XH Connector Kit | 11.99 $ | Amazon | |
| 2 | Dupont Jumper Wires | 9.79 $ | Amazon | |
| TOTAL | 341.84 $ |
- What parts and systems were made?¶
There are several subsystems and parts that must be made in this Final project:
- Box building
-
Toilet section with automatic litter cleaning system mechanism. It has several parts, including:
- drum chamber
- power transmission system
- litter separator system
- Waste Tray
-
An electronic system that regulates the work process of a smart toilet. It has several parts, including:
- Main controller
- Sensors to detect the presence of a cat in the drum, odors in the toilet, the temperature and humidity conditions of the toilet
- Actuator to rotate the drum during the process of automating the separation and cleaning of liters
- Display for status of machine running
- What processes were used?¶
- CNC router : Box house (plywood)
- Laser Cutting : drum chamber
- Electronics Production : PCB (Mini CNC Rolland),
- 3D Printer : Box of PCB board
- Vinyl Cutting : Front display
- What questions were answered?¶
What is the mechanism for sorting and separating feces/pees from liters
- What worked? What didn’t?¶
Overall the system has worked well, including:
- System power supply: able to handle the power needed by the system
- Electronic: able to take sensor data and adjust the output to the motor and display (LED and Buzzer)
- the work order of the system has been running according to the specified sequence
- The drum rotation mechanism is working well
- The feces separation mechanism is already running, but it needs a little improvement on the better sorting mechanism (Need research on technical sorting/separating wood liters that are still good with cat litter)
- How was it evaluated?¶
To make sure everything run well, I evaluated with some tests, namely:
-
functional testing:
- the strength of the material in both the housing and the drum for the litter
- test the motor’s ability to rotate and move the separator (power/torque)
- Test PCB track to make sure MCU can work
- testing programming algorithms to make sure all sensors and working sequences match
- Overall system testing
-
real test with animal behavior : Cats need to be trained first to be able to use this toilet.
- What are the implications?¶
This final project gives more value to wood pellet products that can be used as an absorber in pet litter. Utilization of wood liters is more eco-friendly to the environment. The resulting waste can be used for plant fertilizers For pet-lovers, an automatic pet litter cleaning system will make daily pet care easier.