Actuators

All actuators use Teensy 4.1 + Waveshare CAN transceiver nodes on 250 kbps CAN bus.

Steering (0x200)

Stepper motor with closed-loop analog position feedback.

Control	Closed-loop position
Feedback	Analog potentiometer
ADC Range	350 (left) - 820 (right)
Deadband	±5 ADC counts
Safety	Left/right limit switches

Pins: DIR=4, STEP=5, Right limit=20, Left limit=21, Feedback=A0

CAN Command (2 bytes):

Byte	Value
0	Center flag (0/1)
1	Setpoint (-127 to +127)

Throttle (0x100)

MCP4728 quad-channel 12-bit DAC controls throttle voltage and drive mode lines.

DAC	MCP4728 (I2C 0x60/0x64)
Output Range	0 - 4.096V
Idle Voltage	0.30V
Max Voltage	4.00V
Watchdog	200ms → Neutral + Idle

DAC Channels: A=Throttle, B/C/D=Drive mode lines

Drive Mode Voltages:

Mode	Ch B	Ch C	Ch D
Neutral	3.15V	1.91V	3.20V
Drive	0.00V	1.91V	3.18V
Sport	0.55V	1.88V	0.00V
Reverse	3.15V	0.00V	3.18V

CAN Command (3 bytes):

Brake (0x300)

Linear actuator with H-bridge PWM control.

Pins: RPWM=12 (extend), LPWM=11 (retract), Feedback=A0

CAN Command (2 bytes):

Byte	Value
0	E-STOP flag (0/1)
1	Brake position (0-255)

E-STOP Behavior

When E-STOP activates:

• Throttle: 0V output, Neutral mode

• Brake: Full extension (100%)

• Steering: Holds position