RoboHeart Hercules
ESP32-powered robotics board with motor drivers and sensor inputs - great for educational robotics kits.
RoboHeart Hercules Pinout
26 pins · 2.54 mm pitch| Pin | GPIO | Labels | Status | Capabilities | Notes |
|---|---|---|---|---|---|
| 1 | 0 | BUTTON_ROBOHEARTG0A11 | strapping | adc | |
| 2 | 1 | G1PWM | uart | - | |
| 3 | 2 | SLEEP_MOTOR_ABCG2A12PWM | strapping | adc | |
| 4 | 3 | G3PWM | uart | - | |
| 5 | 4 | MOTOR_C_IN2A10PWM | safe | adc | |
| 6 | 5 | SSG5PWM | strapping | spi | |
| 7 | 12 | GSM_PWRKEYG12A15PWM | strapping | adc | |
| 8 | 13 | GSM_DTRG13A14PWM | strapping | adc | |
| 9 | 14 | LED_ROBOHEARTGSM_RTSA16PWM | strapping | adc | |
| 10 | 15 | GSM_CTSG15A13PWM | strapping | adc | |
| 11 | 16 | RXD1RXD2G16PWM | safe | - | |
| 12 | 17 | TXD1TXD2G17PWM | safe | - | |
| 13 | 18 | SCKG18PWM | safe | spi | |
| 14 | 19 | MISOG19PWM | safe | spi | |
| 15 | 21 | IMU_SDASDAG21PWM | safe | i2c | |
| 16 | 22 | IMU_SCLSCLG22PWM | safe | i2c | |
| 17 | 23 | MOSIG23PWM | safe | spi | |
| 18 | 25 | MOTOR_A_IN1G25DAC1A18PWM | safe | adc · dac | |
| 19 | 26 | MOTOR_A_IN2G26DAC2A19PWM | safe | adc · dac | |
| 20 | 27 | MOTOR_B_IN1A17PWM | safe | adc | |
| 21 | 32 | MOTOR_B_IN2A4PWM | safe | adc | |
| 22 | 33 | MOTOR_C_IN1A5PWM | safe | adc | |
| 23 | 34 | RXG34A6 | strapping | adc · uart | |
| 24 | 35 | TXG35A7 | strapping | adc · uart | |
| 25 | 36 | BATTERY_PING36A0 | strapping | adc | |
| 26 | 39 | A3 | strapping | adc |
Start with these
13 pins with no boot or system involvementFreely assignable - no strapping, flash, USB or JTAG duties. Ideal first picks for buttons, sensors and LEDs.
Fine - with a little care
13 pins · 12 things to knowBUTTON_ROBOHEARTGPIO0 Bootstrapping pin (enter bootloader when low); internal pull-up. Strapping
Must be HIGH during boot for normal startup; if held LOW on reset, forces flash programming mode.
G1GPIO1 Default UART0 TX pin for USB-serial programming and console. UART
Connected to on-board USB-UART for uploading and logs; drives serial output at boot, so using as GPIO can disrupt programming or console.
SLEEP_MOTOR_ABCGPIO2 Bootstrapping pin (must be low or floating at reset); internal pull-down. Strapping
If driven HIGH on reset (while IO0 is LOW), selects an unsupported SDIO boot mode, causing boot failure.
G3GPIO3 Default UART0 RX pin for USB-serial programming (console input). UART
Used for receiving data from USB-UART (programming); also pulled HIGH at boot for console communication, so using as GPIO can disrupt uploads.
SSGPIO5 Bootstrapping pin; internal pull-up; VSPI CS0 (default SPI chip-select); acts as FSPIWP (flash write-protect) on internal-flash variants. Strapping
Must be HIGH during boot; if pulled LOW at reset, alters SDIO slave timing and may prevent normal boot.
GSM_PWRKEYGPIO12 Bootstrapping pin; JTAG TDI; sets flash voltage (VDD_SDIO); also HSPIQ (flash data line). Strapping
Keep LOW during boot (internal PD); pulling HIGH at reset selects 1.8V flash mode, causing flash brownout if 3.3V flash is used.
GSM_DTRGPIO13 JTAG clock pin (TCK); also ADC2 channel 4 / Touch4 input. JTAG
Used for JTAG debugging (TCK); avoid using as GPIO if JTAG is needed.
LED_ROBOHEARTGPIO14 JTAG mode select pin (TMS); also HSPI CLK and PWM-capable GPIO. JTAG
Used for JTAG debugging (TMS); driving it as GPIO may interfere with JTAG or produce spurious signals at boot.
GSM_CTSGPIO15 Bootstrapping pin; JTAG TDO; controls UART0 boot log output; also HSPICS0 (secondary SPI CS). Strapping
Keep HIGH during boot (internal PU); if LOW on reset, bootloader log is silenced and boot mode may change.
RXGPIO34 Input-only GPIO (no output driver); ADC1 channel 6. Other
Cannot be used as output (no drive capability); only suitable for analog/digital input.
TXGPIO35A3GPIO39 Input-only GPIOs with ADC1 channels - no output driver Other
Cannot be used as output; only suitable for input.
- TXInput-only GPIO (no output driver); ADC1 channel 7.
- A3Input-only GPIO (no output); ADC1 channel 3, Hall sensor VN.
BATTERY_PINGPIO36 Input-only GPIO (no output); ADC1 channel 0, Hall sensor VP. Other
Cannot be used as output; only suitable for input (e.g., analog read).
The RoboHeart Hercules pinout brings out 26 GPIO pins at a 2.54 mm pitch - every one of them usable in your project.
For peripherals, I²C is mapped to SDA on GPIO21 and SCL on GPIO22; the SPI bus (MOSI, MISO, SCK, SS) is broken out in full; TX/RX on GPIO35 and GPIO34 cover serial logging and flashing.
On the analog side there are 16 ADC-capable pins for sensors and battery monitoring and 2 true DAC outputs.
If you want zero surprises, MOTOR_C_IN2, RXD1, TXD1, SCK and 9 more are free of any such role - the safest first picks. 13 of the exposed pins carry boot-time or system duties on the ESP32 (BUTTON_ROBOHEART, G1, SLEEP_MOTOR_ABC and 10 more).
Getting started
flash your first firmware in ~2 minutesBoard: ESP32 Dev Module Flash Size: 4MB (32Mb) Flash Mode: DIO Partition Scheme: Default 4MB with spiffs (1.2MB APP/1.5MB SPIFFS) Upload Speed: 921600
// toggle GPIO4 - wire an LED and resistor to it
void setup() {
pinMode(4, OUTPUT);
}
void loop() {
digitalWrite(4, HIGH); delay(500);
digitalWrite(4, LOW); delay(500);
}[env:roboheart_hercules]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200
upload_speed = 921600esp32dev - or type it after board =.esp32:
board: esp32dev
variant: esp32
framework:
type: esp-idf
# blink - GPIO4
output:
- platform: gpio
pin: 4
id: led_out
light:
- platform: binary
name: "LED"
output: led_outesp32dev (same ids as PlatformIO).esptool.py --chip esp32 --port /dev/ttyACM0 \
--baud 921600 write_flash 0x1000 firmware.bin--port = your /dev/tty* (macOS/Linux) or COMx (Windows).Specifications
ESP32 · 61 × 61 mm · vs other ESP32 chips →Dimensions
About this board
At its core is the ESP32 - a dual-core Xtensa with both Bluetooth Classic and BLE.
Expect to pay about $42.00 - above the ~$20 typical for ESP32 boards.
Onboard you'll find a Grove connector, an IMU, battery charging via JST-PH and status LEDs (User).
- 3-channel DC motor driver (Texas Instruments DRV8836); drives up to 3 DC motors or 1 stepper motor
- JTAG debug connector for hardware debugging
- 1S LiPo support: onboard charging with reverse-battery, over-charge and over-discharge protection
- Two Grove connectors (one UART, one I2C)
- Built on the ESP32-WROOM-32 module
Where to buy
prices are typical street pricesResources
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