Picopet

Pico Pet

A virtual pet that requires the user to complete pomodoros for the health of their pet.

Hardware

• Raspberry Pi Pico
  • Raspberry Pi Pico for development
  • Waveshare RP2040-Tiny for release
• Waveshare 1.44" LCD
• DS3231
• Any 5v to 3v3 shifter for the DS3231, for example
• Any 5v speaker or buzzer, for example
• Any 3v-5v vibrating motor, for example

NVM Utilization

The NVM (Non-Volatile Memory) module included with the DS3231 provides 4KiB arranged in 512 pages of 8 bytes each.

Permanent storage must be serializable to a specified number of pages, and write to an assigned page address.

Pages are addressed from hexidecimal 0x000 to 0x1ff.

note: If the NVM becomes corrupted, try changing the const NVM_SENTINEL to force a header guard check failure. This will factory reset the device, and all data will be lost.

Max juice is 9999ml as a u16

Max HP = Daily Hunger + 4

Last Fed Year is probably excessive, but it'd be a weird bug if someone started the pet up after exactly 1 year, and their pet showed no signs of missed days of hunger...

Pin Out For Raspberry Pico

graph LR
    subgraph RP2040
        Pin1
        Pin2
        %%Pin3[GND]
        Pin4
        Pin5
        Pin6
        Pin7
        %%Pin8[GND]
        Pin9
        %%Pin10
        Pin11
        Pin12
        %%Pin13[GND]
        Pin14
        Pin15
        Pin16
        Pin17
        %%Pin18[GND]
        %%Pin19
        Pin20
        %%Pin21
        Pin22

Pinout for Waveshare RP2040-Tiny

graph LR
    subgraph RP2040-Tiny
        TinyPin0
        TinyPin1
        TinyPin2
        TinyPin3
        TinyPin4
        TinyPin5
        TinyPin6
        %%TinyPin7
        TinyPin8
        TinyPin9
        TinyPin10
        TinyPin11
        TinyPin12
        TinyPin13
        %%TinyPin14
        TinyPin15
        %%TinyPin16
        %%TinyPin17
        %%TinyPin18
        TinyPin19
        %%TinyPin20
        %%TinyPin21[3V3]

Development Breakboard Build

Below are my recommendations for how to build the development board.

Shopping List

All amazon links are tracking free and affiliate free; feel free to source these where you wish, but compatability is not guaranteed for other similar products. The current iteration of the software is absolutely tied to the LCD module below, as well as the combination DS3231 & AT24C32 board. Theoretically any RTC and NVM module could replace the aformentioned, but the I2C addresses have been set to match the product below. Additionally, any ST7735S driven 128x128 display could be adapted. All four buttons provided on the waveshare LCD hat are used as well.

• Components
  • Expansion Board https://www.amazon.com/dp/B08X6FPRYF/
  • Breakout Board https://www.amazon.com/dp/B0B982B9HV/
  • Breadboard https://www.amazon.com/dp/B07VFFXPH3/
  • LCD Module https://www.amazon.com/dp/B0957NJP97/
  • Raspberry Pico w/ presoldered headers https://www.amazon.com/dp/B08X7HN2VG/
  • RTC Board https://www.amazon.com/dp/B09KPC8JZQ/
  • Vibrating Motor https://www.amazon.com/dp/B073YFR5WR/
  • Piezo Buzzer https://www.amazon.com/dp/B07P6X9YX7/
• Tools/Resources
  • 22 AWG solid hookup wire https://www.amazon.com/dp/B07TX6BX47/
  • 22 AWG wire stripper https://www.amazon.com/dp/B06X9875Z7/
  • CR2032 battery https://www.amazon.com/dp/B071D4DKTZ/
  • Command strip https://www.amazon.com/dp/B07P32RHQ4/

Assembly

1. Socket the Raspberry Pico into center of the Expansion Board.
2. Socket the LCD Module into the left slot of the Expansion Board.
3. Using a command strip, attach the breadboard to the flat side of the breakout board.
   • The 1A point of the breadboard should be in the top left, near where the word VBUS is printed on the back of the breakout board.
   • While many breadboards do come with stickers, there is often no solid insulating layer for the conductive rails, and the breakout board has sharp solder points that can stab through this thin soft layer. Whatever you do, I recommend insulating these two boards or you will risk a short...
4. Connect the breakout terminal VSYS and tie point 1A on the breadboard, preferably using a red wire.
   • I recommend running this wire over the top of the board rather than the side as it would be natural to do, because there will be essentially no space between the Raspberry Pico and this specific Breakout Board when they are eventually mated.
5. Connect the breakout terminal GND (the one adjacent to VSYS) and tie point 2A on the breadboard, preferably using a black wire.
   • Again, I recommend running this wire over the top of the board.
6. Connect the data lines to the breadboard, this time allowing the wires to wrap around the side of the board (recommended colors in parenthesis):
   • GP0 to J1 (green)
   • GP1 to J2 (white)
   • GP4 to J5 (yellow)
   • GP5 to J6 (blue)
   • GP6 to J7 (green)
7. Connect new lines on the breadboard for the RTC module:
   • C2 to C3 (black)
   • D1 to D4 (red)
   • H1 to B5 (green)
   • H2 to B6 (white)
   • H6 to B7 (blue) (I recommend routing this cable up then following the other 2 data lines)
8. Connect new lines on the breadboard for the piezo buzzer:
   • G5 to F17 (orange)
   • E2 to G13 (black) (I recommend routing this along the top side, then down the gap I left in the I column)
9. Connect new lines on the breadboard for the vibration motor:
   • G7 to K16 (green)
   • F13 to F15 (black)
10. Stick the vibration motor onto the bottom of the breadboard.
11. Attach the vibration motor wires (letting the wires lay to the right):
    • red wire to G16
    • blue wire to G15
12. Place the piezo buzzer onto pins J17 and J13 (placement will secure the vibration motor wires)
13. Insert a CR2032 battery into the RTC module.
14. Place the RTC module onto pins A3, A4, A5, A6, A7, and A8.
15. Finally, socket the breakout board onto the right slot of the Expansion Board.

Development Environment Setup

NixOS

I recommend running the following to open the VSCodium development environment:

nix develop --command codium .

You can of course just use whatever text editor you like, and simply enter the flake in a terminal with:

nix develop

Other Linux Distros

You'll need Rust installed and set to nightly-2023-11-16. Other versions may not be supported. You will likely also need udev to detect the raspberry pico. To use the makefile, you'll also want gnu make. You can review the flake.nix and attempt to reproduce it in your own OS.

First Time Setup

Your first time opening this repo, you'll need to setup the dependencies and enable the thumbv6m-none-eabi target. This has been automated for you:

make init

Running The Code

The build process performs a number of actions. The sprites will be converted from PNG files to raw binary files containing RGB332 data. Fonts will be converted from PNG files to binary files containg black&white data. The custom PEAT audio files will be converted from plaintext files to the binary custom BEAT format. With all assets converted, the project will finally build and attempt to upload.

All of this is as simple as invoking:

make run

Attributions

Placeholder artwork (lofi.png) copyright belongs to Juan Pablo Machado.