An open-source remote controller based on ESP32 with dual analog joysticks, designed for DIY robotics projects.
Firmware is a PlatformIO project located in the DJC-Firmware directory. All dependencies are declared and managed in platformio.ini.
The project uses:
A makefile wraps common PlatformIO commands for convenience.
| Command | Action | Note |
|---|---|---|
make |
pio run |
Compile the project |
make u |
pio run --target upload |
Compile and upload to the ESP32 |
make m |
pio device monitor |
Open serial monitor |
make clean |
pio run --target clean |
Delete compiled objects |
| Feature | Status |
|---|---|
| Dual joystick with calibration | Implemented |
| ST7735 display (SPI) | Implemented |
| ESPNOW peer discovery & connection | Implemented |
| Raw and MAVLink control modes | Implemented (Basic) |
| Persistent configuration (NVS) | Implemented |
| MAVLink telemetry (partial) | SCALED_IMU, ATTITUDE_QUATERNION, SERIAL_CONTROL messages supported |
| Peer explorer with signal age | Implemented (shows last seen time) |
| On‑screen text input (virtual keyboard) | Implemented (Basic) |
The device operates in three modes. Switching between UI Navigation and Control is done with the left button; Virtual Keyboard Input appears automatically when a text field is activated.
| Mode | Purpose | Activation |
|---|---|---|
| UI Navigation | Menu navigation and widget interaction | Default after power‑on; return from Control by pressing left button |
| Control | Transmit joystick data over ESPNOW | Left button from UI Navigation |
| Virtual Keyboard Input | Text entry | Automatically when a text field is activated |
| Input | UI Navigation | Control (Raw) | Control (MAVLink) | Virtual Keyboard Input |
|---|---|---|---|---|
| Left stick X | Unused | left_x |
Yaw |
Unused |
| Left stick Y | Unused | left_y |
Thrust |
Unused |
| Right stick X | Change value of active widget (left/right) | right_x |
Roll |
Move cursor horizontally on keyboard |
| Right stick Y | Move cursor between widgets (up/down) | right_y |
Pitch |
Move cursor vertically on keyboard |
| Left button | Switch to Control | Return to UI Navigation | Return to UI Navigation | Close virtual keyboard |
| Right button | Activate selected widget (press, follow link) | Ignored | Ignored | Enter the selected key |
- When the virtual keyboard is active, the left button closes it and does not switch modes.
- In Control mode, the right joystick does not affect the UI – all its movements are transmitted.
- Only ST7735 display is currently supported
- MAVLink telemetry limited to basic IMU/attitude
- No CLI, no sleep
The project roadmap is maintained in GitHub Issues.
View open issues and planned features
Click to see high‑level planned items
- Finalize power supply documentation
- KiCad schematic and single‑sided PCB shield
- Idle sleep for power saving
- Calibration visual feedback
- Custom peer names/aliases
- Extended MAVLink telemetry
- CLI over Serial
- SSD1306 support
- Hybrid storage (LittleFS + SD card)
| Group | Component | Part / Model | Qty | Notes |
|---|---|---|---|---|
| MCU | ESP32 DevKit | ESP32‑WROOM‑32 (V4) | 1 | Any DevKit variant works |
| Power | Li‑ion cell | 18650 1S1P | 1 | Protected or unprotected (BMS required) |
| Boost converter | XR2981 module | 1 | Step‑up to 5V | |
| Charger (planned) | TP4056 module | 1 | With battery protection (DW01) | |
| Power switch | KCD‑11‑2P | 1 | Rocker switch | |
| Controls | Joystick | HW‑504 | 2 | Analog, 5V (works at 3.3V) |
| Micro switch | V‑153‑1C25 (NO) | 2 | External button | |
| Display | TFT LCD | ST7735 160×128 SPI | 1 | With SD‑card slot |
| Comm | Radio | ESPNOW (integrated) | – | Direct ESP32‑to‑ESP32 |
| Name | Component | № | Pin | Board Network |
|---|---|---|---|---|
| Joystick Left | HW-504 | 1 | GND | Devboard-GND |
| 2 | +5V | Devboard-3V3 | ||
| 3 | VRX | Devboard-GPIO_32 | ||
| 4 | VRY | Devboard-GPIO_33 | ||
| 5 | SW | NC | ||
| Joystick Right | HW-504 | 1 | GND | Devboard-GND |
| 2 | +5V | Devboard-3V3 | ||
| 3 | VRX | Devboard-GPIO_34 | ||
| 4 | VRY | Devboard-GPIO_35 | ||
| 5 | SW | NC | ||
| Button Left | V-153-1C25 | 1 | COM | Devboard-GND |
| 2 | NO | Devboard-GPIO_14 | ||
| 3 | NC | NC | ||
| Button Right | V-153-1C25 | 1 | COM | Devboard-GND |
| 2 | NO | Devboard-GPIO_4 | ||
| 3 | NC | NC | ||
| Display | ST7735 | 1 | LED | Devboard-5V |
| (Module SPI 160x128) | 2 | SCK | Devboard-GPIO_18 | |
| 3 | MOSI | Devboard-GPIO_23 | ||
| 4 | DC | Devboard-GPIO_22 | ||
| 5 | Reset | Devboard-GPIO_17 | ||
| 6 | CS | Devboard-GPIO_5 | ||
| 7 | GND | Devboard-GND | ||
| 8 | VCC | Devboard-3V3 | ||
| Power Switch | KCD-11-2P | 1 | COM | B+ |
| 2 | NO | PowerSwitch-NO | ||
| Voltage Converter | XR2981 | X1-1 | OUT+ | Devboard-5V |
| (Step-up Module) | X1-2 | OUT- | Devboard-GND | |
| X2-1 | IN+ | PowerSwitch-NO | ||
| X2-2 | IN- | B- | ||
| Battery Sense | Resistor R1 (100 kΩ) | 1 | – | PowerSwitch‑NO |
| 2 | – | Devboard‑GPIO_36 | ||
| Resistor R2 (33 kΩ) | 1 | – | Devboard‑GPIO_36 | |
| 2 | – | Devboard‑GND | ||
| Capacitor C1 (0.1 µF) | 1 | – | Devboard‑GPIO_36 | |
| 2 | – | Devboard‑GND |
NC means Not Connected
Devboard means ESP32 Devkit v4 prototyping board
ST7735 backlight LED requires a current‑limiting resistor (440Ω, e.g., two 220Ω in series) when powered from 5V.
Buttons are external micro switches
NO(normally open) connected between GND and the respective GPIO. Internal pull‑ups are enabled in firmware.B+ and B- denote battery contacts
| Left Header | Status | Project Assignment | Right Header | Status | Project Assignment |
|---|---|---|---|---|---|
| 3V3 | ✓ | Logic power | GND | ✓ | Common ground |
| EN | ✓ | Reset (EN button) | GPIO23 | ✓ | SPI MOSI (display + SD) |
| GPIO 36 | ✓ | Battery voltage divider | GPIO 22 | ✓ | Display DC |
| GPIO 39 | ○ | Free (input only) | GPIO 1 | ✓ | UART0 TX (Serial debug) |
| GPIO 34 | ✓ | Right joystick X | GPIO 3 | ✓ | UART0 RX (Serial debug) |
| GPIO 35 | ✓ | Right joystick Y | GPIO 21 | ○ | Free (reserved for I2C SDA) |
| GPIO 32 | ✓ | Left joystick X | GPIO 19 | ✓ | SPI MISO (SD card) |
| GPIO 33 | ✓ | Left joystick Y | GPIO 18 | ✓ | SPI SCK (display + SD) |
| GPIO 25 | ○ | Free (DAC) | GPIO 5 | ✓ | SPI CS (display) |
| GPIO 26 | ○ | Free (DAC) | GPIO 17 | ✓ | Display RESET |
| GPIO 27 | ○ | Free | GPIO 16 | ✓ | SPI CS (SD card) |
| GPIO 14 | ✓ | Left button | GPIO 4 | ✓ | Right button |
| GPIO 12 | ✗ | Avoid (MTDI) | GPIO 0 | ✓ | BOOT button (use with caution) |
| GND | ✓ | Common ground | GPIO 2 | ○ | Free (strapping, use with care) |
| VIN | ✓ | 5V input (from XR2981) | GPIO 15 | ○ | Free (strapping, use with care) |
Symbol Meaning Note ✓ Occupied Already used in the project or reserved ○ Free Available for new components ✗ Unavailable Not recommended for use (boot conflicts)
Feature Used pins Note MTDI GPIO 12 controls flash voltage at startup; using it may cause boot instability UART0 GPIO 1 / GPIO 3 Serial BOOT GPIO 0 It can be used as GPIO if held high at boot. GPIO 39 input-only and lacks an internal pull‑up resistor DAC GPIO 25 / GPIO 26 Can be used as DAC outputs Strapping GPIO 2 / GPIO 15 Freed in this design; safe to use with care (must be low at boot)
3D models (Kompas 3D format) are located in Models-Legacy (outdated) and Models (under development).
No production‑ready files yet.
v0.1.0(SSD1306 display)v0.1.1(Using ST7735 display)
v0.2.0(Add microswitch buttons)v0.2.1(Improved cable management)
This project is licensed under the GNU General Public License v3.0 or later (SPDX: GPL-3.0-or-later).
See the LICENSE file for the full text.
