Schematics

Electronic schematics for all three Robomates PCBs. Designed in KiCad.

Main PCB

The central board carrying the ESP32, IMU, crypto chip, radio, LED driver, and battery management.

Main PCB
📄 Download Main PCB Schematic (PDF)

Key Components

ComponentPartPurpose
MCUESP32-S3Dual-core processor, Wi-Fi + BLE
IMUMPU60506-axis gyroscope + accelerometer
CryptoATECC508AHardware ECDSA P-256 identity
RadioCC1101Sub-GHz RF transceiver (869.525 MHz)
LEDs12× WS2812BAddressable RGB LEDs
Temp sensorTMP117High-accuracy temperature (main board)
UVPExternal chip3.0 V undervoltage protection

I2C Bus Architecture

BusPinsSpeedDevices
Primary SDA=19, SCL=23 400 kHz MPU6050, Right motor encoder (AS5600), Main TMP117, Right TMP117
Secondary SDA=21, SCL=22 200 kHz ATECC508A, Left motor encoder (AS5600), Left TMP117

Left Motor PCB

Motor driver board for the left BLDC motor.

Left Motor PCB
📄 Download Left Motor PCB Schematic (PDF)
ComponentPartPurpose
Motor driver3-phase PWMBLDC field-oriented control
EncoderAS5600Magnetic rotary position sensor
Temp sensorTMP117Motor temperature monitoring
Phase AGPIO 25
Phase BGPIO 33
Phase CGPIO 32
EnableGPIO 13

Right Motor PCB

Motor driver board for the right BLDC motor.

Right Motor PCB
📄 Download Right Motor PCB Schematic (PDF)
ComponentPartPurpose
Motor driver3-phase PWMBLDC field-oriented control
EncoderAS5600Magnetic rotary position sensor
Temp sensorTMP117Motor temperature monitoring
Phase AGPIO 14
Phase BGPIO 27
Phase CGPIO 26
EnableGPIO 12

Motor Specifications

TypeBLDC, 3-phase
Pole pairs7
Phase resistance20.0 Ω
Voltage limit9 V
ControlFOC (SimpleFOC 2.3.2)
EncoderAS5600 magnetic (I2C)

Radio (CC1101)

Frequency869.525 MHz
ModulationFSK
Bit rate38.4 kbps
TX power10 dBm
Deviation20.0 kHz
RX bandwidth135.0 kHz
SPI SCKGPIO 2
SPI MISOGPIO 35
SPI MOSIGPIO 15
SPI CSGPIO 4

Power System

BatterySingle-cell LiPo
Voltage range2500–4200 mV
ADCGPIO 36, 12-bit, 2:1 divider
Low battery3800 mV for 40 s
Discharge spike3100 mV within 5 min
Hardware UVP3.0 V cutoff