# # train controller based on rp2040 RPi Pico board with micropython rev. 1.20 # # functionality: # controls direction and speed of a model train # does control two independent tracks # gives status indication to user with LEDs for direction, stop, overlead # # all objects related to hardware are defined in module cfg.py. # If you use different Pins or interfaces for your implementation adjust cfg.py accordingly # # # # by wolf2810 # initial rev. 3-Oct-2023 # 6-Oct-2023 : implementation of overload management # from track_controller import Track_control import cfg import time # if cfg.debug == 1: import print_status # instantiate track controller's rails rail1 = Track_control(cfg.R1Dir, cfg.R1Enable, cfg.R1Ovl, cfg.R1OLreset) rail2 = Track_control(cfg.R2Dir, cfg.R2Enable, cfg.R2Ovl, cfg.R2OLreset) # define and initialize power supplies pws = cfg.track_power rail1_pws = 0 # power supply 0 for rail1 rail2_pws = 1 # power supply 1 for rail2 pws.write(0, rail1_pws) pws.write(0, rail2_pws) if cfg.debug > 1: print("track controller for rail1 and rail2 initialized, power off") OL_counter1 = 0 # loop counter for rail1 overload condition OL_counter2 = 0 # loop counter for rail2 overload condition # define functions def speed_input(rail_pot): # read potentiometer and return values for setting the track power and direction # function expects and ADC object # pot_value = rail_pot.read_u16() # determine direction and speed. Map to 0-255 range of rail power supply. if pot_value in range(cfg.stop_lower, cfg.stop_upper): # value is in dead band around mid point if cfg.debug > 1: print("speed= 0, direction= stop") return(0, "stop") if pot_value > cfg.stop_upper: # to the right of mid point, direction forward speed = int((255-cfg.min_speed) * (pot_value-cfg.stop_upper) / (cfg.ADCmax - cfg.stop_upper)) + cfg.min_speed if cfg.debug > 1: print("speed= ", int(speed), " direction= forward") return(speed, "forward") if pot_value < cfg.stop_lower: # to the left of mid point, direction reverse speed = int((255-cfg.min_speed) * (cfg.stop_lower-pot_value) / cfg.stop_lower) + cfg.min_speed if cfg.debug > 1: print("speed= ", int(speed), " direction= reverse") return(speed, "reverse") def toggle(LED): # function to toggle state of an LED # expects a Pin object if LED.value(): # print("LED off") LED.value(0) elif not LED.value(): LED.value(1) # print("LED on") # start of program try: # wait for both pots to be in stop position for safe startup speed1, rail1_dir = speed_input(cfg.rail1_pot) speed2, rail2_dir = speed_input(cfg.rail2_pot) while rail1_dir != "stop": if cfg.debug > 0: print("rail 1 potentiometer not on stop position", end="") print(".", end="") toggle(cfg.rail1_LED) time.sleep_ms(500) speed1, rail1_dir = speed_input(cfg.rail1_pot) while rail2_dir != "stop": if cfg.debug > 1: print("rail 2 potentiometer not on stop position", end="\r") toggle(cfg.rail2_LED) time.sleep_ms(500) speed2, rail2_dir = speed_input(cfg.rail2_pot) # Both Potentiometers on stop position, start main loop cfg.rail1_LED.value(1) cfg.rail1_status["direction"] = "stop" cfg.rail2_LED.value(1) cfg.rail2_status["direction"] = "stop" # start of main loop if cfg.debug == 1: # clear terminal to enable status printout at top left position print_status.clear_terminal() # # start of control loop # while True: # # control rail 1 # # read speed and direction speed, rail_dir = speed_input(cfg.rail1_pot) # check for overload condition if rail1.OL_test() is True: # if cfg.debug > 1: print("rail 1 overload detected", end="\r") # switch off rail power pws.write(0, rail1_pws) rail1.enable(False) # update status cfg.rail1_status["power"] = "off" cfg.rail1_status["overload"] = True cfg.rail1_status["speed"] = 0 if cfg.debug == 1: print_status.print_rail_status() # wait for stop position if cfg.rail1_status["direction"] != "stop": OL_counter1 += 1 if OL_counter1 > 20: toggle(cfg.rail1_LED) OL_counter1 = 0 if rail_dir == "stop": # in stop position, reset overload condition now cfg.rail1_status["direction"] = "stop" resetted = rail1.OL_reset() if resetted is True: # overload condition removed cfg.rail1_status["overload"] = False OL_counter1 = 0 # reset loop counter if cfg.debug > 1: print("rail 1 overload condition removed", end="\r") else: # overload condition prevails if cfg.debug > 1: print("rail 1 overload condition prevails", end="\r") else: # no overload condition if rail_dir == "stop": # stop the train and update status pws.write(0, rail1_pws) # power supply off rail1.enable(False) # switch off track power cfg.rail1_status["direction"] = "stop" cfg.rail1_status["power"] = "off" cfg.rail1_status["speed"] = 0 cfg.rail1_LED.value(1) # STOP LED on if cfg.debug > 1: print("rail 1 STOP position ", end="\r") else: # run the train rail1.direction(rail_dir) rail1.enable(True) # track power on cfg.rail1_status["power"] = "on" cfg.rail1_LED.value(0) # "Stop" LED off # check if train was at stop if cfg.rail1_status["direction"] == "stop": # set power supply to break free power and wait to allow train starts moving pws.write(cfg.break_free, rail1_pws) time.sleep_ms(cfg.break_free_time) cfg.rail1_status["speed"] = cfg.break_free # update status direction cfg.rail1_status["direction"] = rail_dir if cfg.debug > 1: print("rail 1 speed is ", str(speed), " direction is ", rail_dir, " ", end="\r") else: pws.write(speed, rail1_pws) cfg.rail1_status["speed"] = speed # update status direction cfg.rail1_status["direction"] = rail_dir if cfg.debug > 1: print("rail 1 speed is ", str(speed), " direction is ", rail_dir, " ", end="\r") # # control rail 2 # # read speed and direction speed, rail_dir = speed_input(cfg.rail2_pot) # check for overload condition if rail2.OL_test() is True: # if cfg.debug > 1: print("rail 2 overload detected", end="\r") # switch off rail power rail2.enable(False) pws.write(0, rail2_pws) # update status cfg.rail2_status["power"] = "off" cfg.rail2_status["overload"] = True cfg.rail2_status["speed"] = 0 if cfg.debug == 1: print_status.print_rail_status() # wait for stop position if cfg.rail2_status["direction"] != "stop": OL_counter2 += 1 if OL_counter2 > 50: toggle(cfg.rail2_LED) OL_counter2 = 0 if rail_dir == "stop": # in stop position, reset overload condition now cfg.rail2_status["direction"] = "stop" resetted = rail2.OL_reset() if resetted is True: # overload condition removed cfg.rail2_status["overload"] = False OL_counter2 = 0 # reset loop counter if cfg.debug > 1: print("rail 2 overload condition removed", end="\r") else: # overload condition prevails if cfg.debug > 1: print("rail 2 overload condition prevails", end="\r") else: # no overload condition if rail_dir == "stop": # stop the train and update status pws.write(0, rail2_pws) # power supply off rail2.enable(False) # switch off track power cfg.rail2_status["direction"] = "stop" cfg.rail2_status["power"] = "off" cfg.rail2_status["speed"] = 0 cfg.rail2_LED.value(1) # STOP LED on if cfg.debug > 1: print("rail 2 STOP position ", end="\r") else: # run the train rail2.direction(rail_dir) rail2.enable(True) # track power on cfg.rail2_status["power"] = "on" cfg.rail2_LED.value(0) # "Stop" LED off # check if train was at stop if cfg.rail2_status["direction"] == "stop": # set power supply to break free power and wait to allow train starts moving pws.write(cfg.break_free, rail2_pws) time.sleep_ms(cfg.break_free_time) cfg.rail2_status["speed"] = cfg.break_free # update status direction cfg.rail2_status["direction"] = rail_dir if cfg.debug > 1: print("rail 2 speed is ", str(speed), " direction is ", rail_dir, " ", end="\r") else: pws.write(speed, rail2_pws) cfg.rail2_status["speed"] = speed # update status direction cfg.rail2_status["direction"] = rail_dir if cfg.debug > 1: print("rail 2 speed is ", str(speed), " direction is ", rail_dir, " ", end="\r") if cfg.debug == 1: print_status.print_rail_status() # slow down control loop, to enable easier debugging with debug=2 if cfg.debug > 1: # input("press Enter to continue") time.sleep_ms(500) # # End of control loop # except KeyboardInterrupt: print("\n\nGot Ctrl-C exiting program") except ValueError as error: print(error) finally: # pws.shut_down(2) rail1.enable(False) rail2.enable(False) if cfg.debug: print("\nfinally: disabled rail power, exiting ...")