Mini 2DOF Spider Robot

Python gait/locomotion simulation for a custom 2DOF robot with MicroPython/ESP32 cross-communication and GUI design tutorial. The simulation currently ignores friction, vibration, and environmental factors.

Demo video (MP4)

Features

• Gait & Locomotion Simulation - Python-based kinematic modeling
• Real-time Communication - MicroPython/ESP32 ↔ PC cross-communication
• GUI Design Tutorial - Non-code Espressif GUI Builder setup

Prerequisites

• Python 3.12 with Robotics Toolbox from Peter Corke.

• MicroPython - ThonnyIDE

• Espressif C / IDF extension - Low-level control

• NXP GUI Guider - Interface design

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Design in NXP GUI Guider - Generate code - Espressif ESP-IDF Integration

Layer 1 — Design Tool: NXP GUI Guidera

• After finish your design, you will have the following files. | File | Purpose | |---|---| | gui_guider.h | Central lv_ui struct — one named pointer per widget | | gui_guider.c | setup_ui() entry point, animation helpers | | setup_scr_screen.c | All widget creation — sizes, styles, images, fonts | | events_init.c/h | Empty event stubs (generated skeletons) | | widgets_init.c/h | Widget helper utilities |

Layer 2 — implement your generated with lv_ui Struct

The key linking mechanism is the lv_ui struct in gui_guider.h. GUI Guider generates one named pointer per widget you placed in the designer: My case:

typedef struct {
    lv_obj_t *screen;
    lv_obj_t *screen_Spider_function_control;  // button matrix (TROT, SCAN, MOONWALK, SPM)
    lv_obj_t *screen_imgbtn_2;    // UP arrow
    lv_obj_t *screen_imgbtn_3;    // DOWN arrow
    lv_obj_t *screen_imgbtn_4;    // LEFT arrow
    lv_obj_t *screen_imgbtn_5;    // RIGHT arrow
    lv_obj_t *screen_imgbtn_6;    // E-STOP button
    lv_obj_t *screen_telementry;  // sensor data table
    lv_obj_t *screen_speedcontrol; // speed slider
    lv_obj_t *screen_animimg_1;   // robot animation (75 frames)
} lv_ui;

This struct is the contract between GUI Guider's generated code and your hand-written logic. GUI Guider fills in the pointers inside setup_scr_screen.c; your application code reads them to wire up real behaviour.

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Layer 3 — Your Logic: main.c + gui/custom/

The gui/custom/ folder is never overwritten by GUI Guider — it is your safe zone for application code:

gui/custom/
├── custom.c / custom.h    ← custom_init() hook called at boot
└── lv_conf_ext.h          ← LVGL config overrides

The boot sequence in main.c ties everything together:

init_wifi_espnow();                              // 1. Start WiFi + ESP-NOW radio
waveshare_esp32_s3_rgb_lcd_init();               // 2. Init display hardware
setup_ui(&guider_ui);                            // 3. Run generated code → creates all widgets
wire_biospider_events_to_demo3_ui(&guider_ui);   // 4. Attach YOUR callbacks to widget pointers
create_terminal_log_widget(&guider_ui);          // 5. Add custom terminal overlay
events_init(&guider_ui);                         // 6. Generated event stubs
custom_init(&guider_ui);                         // 7. Your custom_init() hook

The critical step is wire_biospider_events_to_demo3_ui(), which connects generated widget handles to your ESP-NOW send functions:

lv_obj_add_event_cb(ui->screen_imgbtn_2, bio_up_btn_cb,         ...); // UP    → "forward"
lv_obj_add_event_cb(ui->screen_imgbtn_3, bio_down_btn_cb,       ...); // DOWN  → "backward"
lv_obj_add_event_cb(ui->screen_imgbtn_4, bio_left_btn_cb,       ...); // LEFT  → "turn_left"
lv_obj_add_event_cb(ui->screen_imgbtn_5, bio_right_btn_cb,      ...); // RIGHT → "turn_right"
lv_obj_add_event_cb(ui->screen_imgbtn_6, bio_emergency_stop_cb, ...); // E-STOP → "STOP"
lv_obj_add_event_cb(ui->screen_speedcontrol, bio_speed_slider_cb, ...); // speed %

Each callback calls bio_send_movement() which fires esp_now_send() with a JSON command to the MicroPython slave:

// Example: pressing UP sends this to the robot over ESP-NOW
{"cmd":"MOVE","dir":"UP","speed":75}

The slave (main_espnow.py) receives, parses, and maps it to a movement call on the Quad robot class.

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Thanks for Stopping By

This project started as a personal challenge to bridge real-time embedded C, MicroPython, and GUI design into one cohesive robot platform — and it's still evolving.

If you found something useful here — whether it's the ESP-NOW communication pattern, the LVGL integration workflow, or just the gait code — I hope it saves you some time on your own build.

Feel free to:

• Open an issue if you spot something broken
• Fork it and make it your own

Build things, break things, learn things. Have a good one. 🕷️