/*
Step-A-Sketch: A digital etch-a-sketch
Example project for the Stepdance control system.
A part of the Mixing Metaphors Project
// (c) 2025 Ilan Moyer, Jennifer Jacobs, Devon Frost
*/
#define module_driver // tells compiler we're using the Stepdance Driver Module PCB
// This configures pin assignments for the Teensy 4.1
// Machine Selection
// Choose one of the two machines below
#define axidraw
// #define pocket_plotter
#include "stepdance.hpp" // Import the stepdance library
// -- Define Input Ports --
InputPort input_a;
// -- Define Output Ports --
// Output ports generate step and direction electrical signals
// Here, we control two stepper drivers and a servo driver
// We choose names that match the labels on the PCB
OutputPort output_a; // Axidraw left motor
OutputPort output_b; // Axidraw right motor
OutputPort output_c; // Z axis, a servo driver for the AxiDraw
// -- Define Motion Channels --
// Channels track target positions and interface with output ports
// Generally, we need a channel for each output port
// We choose names that match the axes of the AxiDraw's motors
Channel channel_a; //AxiDraw "A" axis --> left motor motion
Channel channel_b; // AxiDraw "B" axis --> right motor motion
Channel channel_z; // AxiDraw "Z" axis --> pen up/down
// -- Define Kinematics --
// Kinematics convert between two coordinate spaces.
// We think in XY, but the axidraw moves in AB according to "CoreXY" (also "HBot") kinematics
KinematicsCoreXY axidraw_kinematics;
// -- Define Encoders --
// Encoders read quadrature input signals and can drive kinematics or other elements
// We use rotary optical encoders for the two etch-a-sketch knobs
Encoder encoder_1; // left knob, controls horizontal
Encoder encoder_2; // right knob, controls vertical
// -- Define Input Button --
Button button_d1;
Button button_d2;
// -- Position Generator for Pen Up/Down --
PositionGenerator position_gen;
// --- GCode Interpreter ---
GCodeInterface gcode_interface;
void setup() {
// -- Configure and start the output ports --
output_a.begin(OUTPUT_A); // "OUTPUT_A" specifies the physical port on the PCB for the output.
output_b.begin(OUTPUT_B);
output_c.begin(OUTPUT_C);
// Enable the output drivers
enable_drivers();
// -- Configure and start the channels --
channel_a.begin(&output_a, SIGNAL_E); // Connects the channel to the "E" signal on "output_a".
// We choose the "E" signal because it results in a step pulse of 7us,
// which is more than long enough for the driver IC
channel_a.invert_output(); // CALL THIS TO INVERT THE MOTOR DIRECTION IF NEEDED
channel_b.begin(&output_b, SIGNAL_E);
channel_b.invert_output();
// #ifdef axidraw
// channel_a.set_ratio(25.4, 2874);
// channel_b.set_ratio(25.4, 2874);
// #endif
// #ifdef pocket_plotter
channel_a.set_ratio(40, 3200); // Sets the input/output transmission ratio for the channel.
channel_b.set_ratio(40, 3200);
// #endif
// This provides a convenience of converting between input units and motor (micro)steps
// For the pocket plotter, 40mm == 3200 steps (1/16 microstepping)
channel_z.begin(&output_c, SIGNAL_E); //servo motor, so we use a long pulse width
channel_z.set_ratio(1, 50); //straight step pass-thru.
// -- Configure and start the input port --
input_a.begin(INPUT_A);
input_a.output_x.set_ratio(0.01, 1); //1 step is 0.01mm
input_a.output_x.map(&axidraw_kinematics.input_x);
input_a.output_y.set_ratio(0.01, 1); //1 step is 0.01mm
input_a.output_y.map(&axidraw_kinematics.input_y);
input_a.output_z.set_ratio(0.01, 1); //1 step is 0.01mm
input_a.output_z.map(&channel_z.input_target_position);
// -- Configure and start the encoders --
encoder_1.begin(ENCODER_1); // "ENCODER_1" specifies the physical port on the PCB
encoder_1.set_ratio(24, 2400); // 24mm per revolution, where 1 rev == 2400 encoder pulses
//We're using a 600CPR encoder, which generates 4 edge transitions per cycle.
encoder_1.invert(); //invert the encoder direction
encoder_1.output.map(&axidraw_kinematics.input_x);
encoder_2.begin(ENCODER_2);
encoder_2.set_ratio(24, 2400);
encoder_2.invert();
encoder_2.output.map(&axidraw_kinematics.input_y); // map the right encoder to the y axis input of the kinematics
// -- Configure and start the kinematics module --
axidraw_kinematics.begin();
axidraw_kinematics.output_a.map(&channel_a.input_target_position);
axidraw_kinematics.output_b.map(&channel_b.input_target_position);
// -- Configure Button --
button_d1.begin(IO_D1, INPUT_PULLDOWN);
button_d1.set_mode(BUTTON_MODE_TOGGLE);
button_d1.set_callback_on_press(&pen_up);
button_d1.set_callback_on_release(&pen_down);
button_d2.begin(IO_D2, INPUT_PULLDOWN);
button_d2.set_mode(BUTTON_MODE_TOGGLE);
button_d2.set_callback_on_press(&motors_enable);
button_d2.set_callback_on_release(&motors_disable);
// -- Configure Position Generator --
position_gen.output.map(&channel_z.input_target_position);
position_gen.begin();
// -- Start the G-Code interface
SerialUSB1.begin(115200);
gcode_interface.begin(&Serial);
gcode_interface.output_x.map(&axidraw_kinematics.input_x);
gcode_interface.output_y.map(&axidraw_kinematics.input_y);
gcode_interface.output_z.map((&channel_z.input_target_position));
// -- Start the stepdance library --
// This activates the system.
dance_start();
}
LoopDelay overhead_delay;
void loop() {
// overhead_delay.periodic_call(&report_overhead, 500);
dance_loop(); // Stepdance loop provides convenience functions, and should be called at the end of the main loop
}
void pen_down(){
position_gen.go(-4, ABSOLUTE, 100);
}
void pen_up(){
position_gen.go(4, ABSOLUTE, 100);
}
void motors_enable(){
enable_drivers();
}
void motors_disable(){
disable_drivers();
}
void report_overhead(){
// Serial.println(channel_z.target_position, 4);
// Serial.println(stepdance_get_cpu_usage(), 4);
}
1.14.0