Automatic white/red light for analog locomotive (DC)

 original article

   Most of the simple analog locomotive use DC voltage with normal or reverse polarity, normal polarity go locomotive forward and reverse voltage go locomotive backward.

   I used for test on breadboard a 5mm bicolour led (red/white) LTW30EEDYJA but for 3mm can be used OSRWPA3132A.

   I designed a simple schematic with additional 3 pieces: 2 diodes (1N4007) and a resistor (680Ω..1kΩ):

   For normal polarity for power supply of the analog locomotive white led is on

and for reverse polarity red led is on

   I make movie named automatic white/red light for loco with a 3 pins led:

Arduino automatic model train

original article

   As a noobie with the model train system and because I haven't too much free space for test with big railways, I search for an automatic model train system, where it used IR module for define frake momment (stop position is not instant, as in rea case, if push brake pedal and car stop is after few meters).

    First I found the video I Made an Automated Model Train With An Arduino! where it used direct control (DC voltage with normal or reversed polarity). I tested manually the functionality of the system with my adapted sketch as in video Automatic Model Train (test)

After that, I found article Back-and-forth train control by Arduino with IR sensor

with PWM control for speed, so I adapt the sketch (my sketch) and made a first test with push a carriage push by me, to see how system work, as in video Automatic Model Train (test 2)

   Finally, I added L298 H-bridge module as in schematic

using same sketch.

    First video is Arduino automatic model train

and second (with an oscilloscope on railway power) is Arduino automatic model train (2)

5-March-2022

    After I clean and greased an old Fleischmann 1966 as in movie 1966 Fleischmann 1306 Shunter: O&K MV9 - Bringing it back to life I make a new video named Fleischmann 1966 on Arduino automatic model train.

   PS: Improved sketch is controlled_model_train_1b.ino where it used for start PWM at 105 (aprox. 40%) not 0, remain maximum at 255 from 255 (100%). This mode to start the loco is useful for old DC motor.

   In next image you can see how automatic system for control the train ("loco") works:

   If train go forward, speed is constant, at maximum, if IR module 2 is actuated, speed decrease slow until train stop. After a small pause, train go backward, with speed increase from zero to maximum, and than IR module 1 is actuated, speed decrease slow to until train stop. Again, after a small pause, train go forward and cycle is repeated, as in next image: