Applications and Implications

This week we had to propose a final project masterpiece. For that we should answer the following questions:

What will it do?

My final project is a smart cat litter box. My main focus is not the self cleaning, but rather tracking health data of my cats. It will use a 20kg load cell to calculate the weight of my cat upon entering and will keep track on how often the gou into the toilet, how long they stay there and if there are some variations.
It also uses a bluetooth module to communicate.

Who's done what beforehand?

There are some commercial smart litter boxes, that track the amount of visits per cad and clean the litterbox itselfe, but as far as I know, there is no litterbox that measures the weight of the cats.

What will you design?

I will design the litterbox aswell as the cleaning mechanism. For my design I referenced the litterbox at my home, to get an idea of how big the litterbox should be.

What materials and components will be used?

I use 18mm plywood as main material for my litterbox, which I painted with hydrophobic paint.
I use acrylic for the entrace door aswell as one of the sidepanel of the litterbox, just so I can demonstrate the functionality of it. Also some parts of the litter-bowl will be acrylic, so that there is no possibility, that the wood sucks in any liquid.
For the movement I use three Nema 17 Steppermorots, two for the Z axis and one for the rotation of the strainer, two 8mm lead screws and nuts.
To lock and unlock the door I used a smal servo motor with some 3D-printed parts.
For the motor brackets, the strainer-bar, the mount for the ultrasonic sensor aswell as the electronic-box, I used 3D-printed PLA.
And for my main PCB I used some external components: A ultrasonic sensor, a 20kg load cell with hx-711 analog to digital converter, a HC-06 bluetooth module, a DS1302 real time clock module, two A4988 stepper motor driver and a SD-CArd module.
As A power supply I used a generic 12V 5A DC Power supply.

Where will come from?

The wood, the paint and the acrylic material can be sourced from a local hardware store.
Nearly everything else can be sourced from Amazon, here are some links:
Nema 17 Stepper Motor
Servo Motor
8mm Lead screw and nut
A4988 Stepper driver
Ultrasonic Sensor
Bluetooth Module
Power supply
A complete BOM will be listed on my final page.

How much will they cost?

Component Price
Case Parts 75€
PCB and main components 15€
Electronic modules and components 50€
Stepper- and Servomotors 25€
Leadscrew and nut 20€
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Total 165€

What parts and systems will be made?

- A AtMega328p based main board
- A complete litterbox from wood
- A litter bowl made from acrylic
- A 3D-printed electronic-box for the main board and all electric components
- A 3D-printed strainer bar
- A the complete moition system for moving the strainer Up/Down and rotating it

What processes will be used?

- PCB milling and soldering for the main board
- Woodworking and CNC cutting for the Litterbox itselfe
- Lasercutting for the litterbox-door, the gitter, the litter bowl
- 3D printing for motor brackets, electronic-box, Sensor-mount, strainer-system

What questions need to be answered?

- Can this become a retail product, ready so be sold?
- Will my cats actualy use it?
Are the better ways to filter a litterbox?

How will it be evaluated?

It can be evaluated via my final presentation video.