GummySlime

GummySlime

A Cheesecake compatible SlimeVR tracker PCB.

Overview

GummySlime is my own take on a Cheesecake PCB. The main features this has over regular Cheesecake PCBs are as follows:

• Designed to be (slightly) possible to solder by hand; this uses 0603 sized SMD components instead of 0402 equivalents. (Emphasis on slightly. You MUST be comfortable with SMD soldering.)
• Use of BMI compatible module PCBs instead of soldering the IMU directly on the board itself.
• Use of the ESP32 MCU instead of now outdated ESP12F modules.
• Exposed pads for adding auxilary modules.

Building

When you order PCBs, remember to change the PCB thickness to 1mm!
Most basic guidelines when building Cheesecake PCBs apply here; the general process is mostly the same. The one "gotcha" you should keep note of while building is the USB-C connector: you should solder it on BEFORE soldering the ESP32 module. It is by far the most difficult component to solder on to the PCB.

BOM

Flashing

You will most likely have to flash using VS Code. Here are all of the relevant settings I personally use for flashing these boards:

platformio.ini

[env:esp32c3]
platform = espressif32 @ 6.7.0
platform_packages =
  framework-arduinoespressif32 @ https://github.com/espressif/arduino-esp32.git#3.0.1
  framework-arduinoespressif32-libs @ https://github.com/espressif/arduino-esp32/releases/download/3.0.1/esp32-arduino-libs-3.0.1.zip
build_flags =
  ${env.build_flags}
  -DESP32C3
  -DARDUINO_USB_MODE=1
  -DARDUINO_USB_CDC_ON_BOOT=1
board = lolin_c3_mini
upload_speed = 921600

defines.h

#define IMU IMU_LSM6DSO
#define SECOND_IMU IMU
#define IMU_ROTATION DEG_270
#define SECOND_IMU_ROTATION DEG_270

#define PRIMARY_IMU_OPTIONAL false
#define SECONDARY_IMU_OPTIONAL true

#define BATTERY_MONITOR BAT_EXTERNAL

#define PIN_IMU_SDA 5
#define PIN_IMU_SCL 4
#define PIN_IMU_INT 6
#define PIN_IMU_INT_2 8
#define LED_PIN LED_OFF
//  #define LED_INVERTED false
#define PIN_BATTERY_LEVEL 3

#define BATTERY_SHIELD_RESISTANCE 0
#define BATTERY_SHIELD_R1 100
#define BATTERY_SHIELD_R2 100