Making realistic working level-crossing lights for model railway - Raspberry Pi Pico + simple code

There is nothing like working track-side equipment to enhance your model railway, and here’s how to make your own realistic level-crossing signs, complete with Raspberry Pi Pico controlled flashing lights - all built from scratch - and all for around £25!
Phase 1: Building and coding the controller, based around a Raspberry Pi Pico WH, complete with buttons to activate the lighting sequence. Here, I’ll run through all the stages: wiring, set-up and the Micropython code required - which is all very doable, even for a relatively inexperienced programmer.
Phase 2: Modelling the signs themselves using surface mounted LEDs, glued behind laminated ink-jet printed boards, internally cabled using fine enamelled wire fed down the post, which acts as a common negative. This is quite a challenging build, incorporating as it does the soldering of small electrical components, but not beyond the skills of more experienced modellers. As well as modern era signs, I’ve got a bonus for Rail Blue fans modelling the 1970s and 80s.
You can download the complete code and a pdf of the sign for printing here: github.com/PaterPracticus/Lev....
This is quite a long video, with some quite detailed information, so feel free to skip about using these timecodes.
Timecodes:
0:00 - Introduction
0:47 - Phase 1: THE CONTROLLER
0:56 - Wiring the Raspberry Pi Pico
3:00 - Pico set up
4:10 - Basic coding for the light sequence
7:53 - Adding the buttons
9:48 - Coding for the buttons
12:18 - Saving the program as main.py
12:34 - Phase 2: MODELLING THE SIGNS
12:39 - Building the scale prototype
13:38 - Surface mounted LEDs
15:42 - Wiring and testing
16:44 - Building the final design
16:50 - Designing and printing the signs
18:05 - Assembly
19:28 - Fitting the LEDs
20:46 - Filling between the LEDs
21:34 - Wiring the signs
21:40 - Making and wiring the post
22:14 - The base of the post
22:53 - Soldering the LEDs
25:42 - Soldering the base
26:25 - Making the light hoods
28:39 - Mounting on the layout
29:39 - Completing all four signs
30:00 - Final wiring to the controller
31:45 - Finishing touches - detailing the base
32:05 - Tweaking the code
32:56 - ‘Keep Crossing Clear’ and detailing the base
33:29 - Adapting for the 1970s and 80s
Components price list:
RaspberryPi Pico WH - £7.20
Breadboard - £3.00
Buttons - about £2.00 for 10
10x Red LEDs - £2.79
10x Orange LEDs - £2.79
Brass Strip - £1.74
Brass Tube - £1.69
Enamelled wire - £1.68
Controller and 4 signs £22.89
Not costed: jumper cables, test LEDs, Veroboard, paper/acetate, heat-shrink tubing, decoder wires and some P&P.

[@andrewstephenson3594]

Hi really enjoyed your video. Makes me think of using the PI pico myself. Just in case you haven't found out yet, The pull up/down command is to make sure that an unconnected input has a definite logic level. With the switch open the input can meander up and down because it has a high impedance (it doesn't take much current to make it high or low) so can be affected by other voltages and currents nearby giving a false input. A common practice is to have pull up resistors (or programmed as pull up) on inputs. To activate the input, the switch connects to ground or 0V. The advantage of this is that if the switch is remote from the input pin no power rail is needed at the switch for operation. This reduces the risk for shorting out the power supply. Hope this helps.

[@paterpracticus]

Great explanation. Thank you.