It looks like you are using signed intergers/numbers for the reading from the light sensor. When it reaches the half way value it wraps around and goes negative. If you simply define the data as an unsigned type does it fix the issue.

Quick update. In esp32/mptask.h there exists: #define MICROPY_TASK_PRIORITY MP_THREAD_PRIORITY #define MICROPY_TASK_STACK_SIZE (8 * 1024) #define MICROPY_TASK_STACK_SIZE_PSRAM (12 * 1024) #define MICROPY_TASK_STACK_LEN (MICROPY_TASK_STACK_SIZE / sizeof(StackType_t)) I believe this is where we could increase the stack size, but I am unsure of the sanity and practicality of this... Thoughts?