Universal Railway Bus unit is first and foremost a convenient and reliable connector, replacing the breadbord and a bunch of wires. A more important feature of URB is the integration of several blocks into a chain, and on this basis the construction of any electronics for layout and control. In other words, it is a universal controller for railway modeling electronics.
Sketches for URB you will find on Arduino Central. So, you can send commands via the I2C bus to any of the end peripherals connected to any URB on the layout. According to the specification, the maximum length I2C bus when using a twisted pair of about eight meters. In practice, with a total cable length of five meters, everything works correctly.
Two serial ports provide the ability to receive commands from two different control devices, or a toggled control from one independent line to another control 2 trains without DDC. For example, if you insert two Bluetooth modules (like HC-06), two gamers on Android smartphone’s can independently control trains using the full version of the ArduinoTrain BtControl Pro app. By using USB, you can manage the layout directly from your computer. Also, you can also use the control of DDC and URB as service block together.
The I2C bus needs resistors pulling the data line to a high potential. You can install resistors of any type on the board. I recommend 10K resistors.
If you do not use outputs with high current load, then ULN2003 is not needed. In this case, for your convenience, on the back of the board jumpers are provided, by closing them with a solder, you can connect the periphery to the screw terminals of the SP4 connector instead of the needles of the DP1 connector. Also you can solder to this place SMD resistors.
Current version PCB: 2.7Make URB
This board uses Arduino NANO. Therefore, the dimensions of URBs are only 60x70 mm, which makes it possible to hide it even inside model building. This solution provides excellent flexibility, maintainability, simple mass production and low cost.
All features Arduino Nano, plus:
Optional: install I2C pull-up resistors and smoothing capacitor for power supply
As you can see, the board is set only passive connectors without any electronic components. But here there is nothing to break! By plugs Arduino components to URB, you get many various options for connecting to the railroad peripheries. You can even set empty URBs along the entire length of the builded layout, and then, if necessary, install the Arduino components in them.
Arduino NANO and optional 3.3 to 5V level converter and 2 bluetooth modules HC-06(05).
HC-05 and HC-06, in fact it, is absolutely identical bluetooth modules with identical chips. One of the chips of these modules is a microcontroller. On the HC-05 there are two additional pins for its programming. There are no such pins on HC-06 and its module is easier to use for my project.Make URB