Page is under construction and model under development!!
The 3D Model - The LED's and the schematic - The 3D-parts - Arduino Software
I have been working some time to create a working Z-scale Railroad Crossing with cantilever and working gates, including blinking LED's on the moving gate.
The first test of the prototype, still not painted. Servo to move the gate is not installed yet, testing using my finger.
The mainproblem is the size and scale. Its so small. I could have created it, etching it in brass or newsilver, and that may have given even a better and more filigree look, but using my new Anycubic Photon Mono resin printer to print all the small pieces, gives a cheap and a result I think is acceptable. I like the result. The printer is a cheap, entrylevel printer, with enough resolution for my needs. I also bought the Anycubic Wash & Cure Machine.
Using a 1.5 mm and 1 mm brasstube to hold all the parts. The other parts are modeled in Fusion 360 and printed using Prima Tough Black resin. This resin is flexible and not break very easy, good to be used on this small parts, where the smallest beams are only 0.4x0.4 mm. The lattice on top of the cantilever have material down to 0.1 mm in width.
The model is created using Autodesk Fusion 360, from images and drawings found on internet, like this item from Western Cullen Hayes: Type 10 Flashing Lights PDF catalog.
For the cantliver, the search on internet has been similar. Since everything is so small in scale 1:220, some parts are bigger than in 1:1 size, but hopefully the proportions of the model look right, on the finished model.
All parts, expect for the brass tubes, are modeled as separte items and printed. Some testing were needed, because of some shrinking of the holes. So the 1.5 pipe, needed resinparts with 1.7 mm holes.
The model can be put together in different configurations, from the version with both cantilever and freestanding gate, to versions with lamps on both sides of the model, like the image below.
The LEDs and the schematic
There is a total number of 9 Red LED's on the singlesided models, 4 on the cantilever, and 5 on the signal with the gate. To reduce the number of wires needed, some clever connections need to be made. Not so unusual for the different double warning light signals, we can connect them using 2 wires for each group and connect the LED's in opposite polarity. For the gate, some thinking was needed, because I want as few wires as possible. I ended up using 3 wires. I explain it more in the schematic.
All the LED's are small 0402 SMD LED's, ordered from China with presoldered thin wires connected. To small for myself to solder it. The link gives you my source on Aliexpress.com, like this Red 402 prewired LED. They are equpped with a red and a blue, very thin wire.
The gates schematics need some extra explanation. LED1 are turned on when the gate is activated, LED2 and LED3 is blinking opposite of each other, like for the double warning flash. To achive that we can use 2 outputs from the microcontroller, and turn one on and the other off, and repeat that for the other cycle. THe LEDs are connected to ground with a resistor, to reduse the current. Since all LED's need about 2,2Volt, with 2 LED's in serie, the voltage drop over the resistor will be 0,6 Volt. The current is long below 20 mA, så the value of the resistor is small.
For the different groups of warning flash LED's, I am using 2 other outputs on the microcontroller, one in LOW state, and the other in HIGH state, creating the flashing effect. Both are in LOW state when the crossing is in idle state. The program I have developed, fades the LED's in and out, giving a nice effect.
The printing of the 3D-model is divided into several parts, to be placed on the brasspipe. The main cantilever is one big part, the same with the ladder, lamps and cross, but for the signal with the gate, there are several parts.
The Arduino Code will be discussed and placed here when its ready.