Petkit T4 ESPHome Firmware

Firmware.Dreams.mp4

Custom. Fully replaces the stock firmware while introducing some extra neat features, as well as native Home Assistant integration.

It's able to work completely offline & without HA, although it's recommended to calibrate the load cell weight sensor before use.

Extra features added

• Top (menu) button: Maintenance mode / Reboot
• Bottom (ok) button: Maintenance done & Level the litter
• Advanced status displaying
• Collected waste amount tracking
• Beep after reaching set amount of litter in maintenance mode
• QR code with a Wi-Fi AP connection shortcut
• Optional Improv-BLE support
• Various internal sensors exposed to HA
• Additional safety checks compared to the stock fw
• Manual motor controls

Yet to implement

• Auto cleaning start (a.k.a. non-kitten mode)
• Pet weight saving
• Multiple pets support
• Extra unknown packets
• Better & more failsafe motor control
• Parametrized MCU init
• Automated calibration
• Dumping the stock calibration data from factory binaries (per-chip)
• Weight as additional safety check

Weight Sensor Calibration

1. Place the T4 on a reasonably flat surface, make sure it's standing on all four its feet, as load cells are attached to each of them.
2. Press the Weight Calibration Zero configuration button until the Weight diagnostic sensor reads positive zero exactly.
3. Put a precisely (to 0.01 kg) known weight on top of the T4.
4. Enter its exact weight in decimal kilograms to Weight Calibration configuration number input and press enter.
5. Remove the weight and check for exact positive zero again, press the button again to reach it.
6. Place the weight again and check for its weight drift, re-input the value if needed (you might need to add/remove a trailing non-significant zero in order for the value to be actually sent and saved).
7. Rinse, repeat as desired (a perfect 0.01 kg precision is known to be reachable on T4).

Thanks to:

• @earlynerd with his repo for the pioneering and enormous help in the reverse engineering.
• @dwyschka for the idea and the upstart (earlynerd/petkit-pura-max-serial-bus#1).
• My loved girlfriend Sharea & my lovely kitty Xayah for the lots of testing.

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Petkit.T4.ESPHome.Firmware.mp4