Please refer to electronics-inventory for a list of available electronics and their state.
Seidentrasse runs on 24V. The trains are controlled digitally through DCC, a system that modulates the data signal onto the 24V connected to the rails by inverting the polarity. By default, this communication is only one-directional. We are not using any bi-The data signal is modeled onto the rails by inverting the polarity of the current.
While with conventional analog model trains, the polarity of the signal determines which direction the train goes in, digital locomotives have a specified forward direction that is independent of the polarity of the track. However, when we construct the network, we still need to make sure not to build loops that create shorts between the two rails, just like with analog trains. If we build rail layouts like that, we need to add interruptor tracks. Locomotives will be able to pass over them without issue since the direction of digital locomotives is not determined by the polarity of the track.
Most hardware we are using is self-developed or using open-source hardware. Since DCC has only a very limited bandwidth, we are only controlling the locomotives via DCC, any switches and other devices are controlled via WiFi/MQTT.
This is the central device that connects to our central computer. It is connected to a 24V DC power supply and modulates the data onto the track. In theory, you can connect multiple central units, as long as they are running on electrically seperated tracks. In practice, we will only use multiple ones if we are forced to do so for electrical reasons.
We are using DCC-EX central units based on arduino and a custom arduino motor shield. They can at most provide 5-6A of power, which as a general rule of thumb means you should not run more than 2 or 3 trains off it.
A booster is a device that repeats the DCC signal using its own power source. Simply put, the booster has two inputs: DCC in, connected to another track or central unit or booster, Power in, connected to a 24V DC power supply and DCC out, connected to a rail.
We are using our own self-developed boosters, which can provide 5-6A of power, so the same limitations for active trains in the area they are responsible for, applies.
Our boosters are able to detect how much current is drawn from the track. This means that they can detect if there is currently current being drawn and they can also react appropriately if the power being drawn is too high or there is a short. (Shorts can be caused very briefly if a locomotive runs over an interruptor track put in to made a looping track work.)
While our boosters don't communicate much, they are equipped with an ESP32-S3 chip and communicate over WiFi. While they are eletrically capable of reading or even manipulating the DCC signal, our firmware is currently not capable of doing so.
Our self-developed sensor controllers can be used to detect where trains are. Instead of feeding the DCC signal directly from the booster to a rail, we feed it to a sensor PCB, which has one input and divides it up onto 10 outputs. It's able to detect which outputs current is being drawn from and report this back to us. This way we can detect where trains are, which is a requirement for proper automatic operations.
Our sensor controllers are equipped with an ESP32-S3 chip and communicate over WiFi.
Important: The sensor controller needs an isolating 10-24V power supply, meaning the power supply must not be grounded. This means that you must not connect a laptop unless it runs off battery. In theory, it can run without a power supply and use the DCC in for power, but this does currently not work reliably yet until we fix an electrical issue.
The Sensor controllers have an expansion slot for our port extension, see below.
Our self-developed switch controller can control up to 8 switches and similar devices. Switches that have a feedback sensor to detect the position of the switch are also supported and the switch controller will be able to report the position back to our software.
Each switch output can also be used to control two simple 12V devices instead. It also features 16 multi-purpose inputs.
The switch controller can be extended using a switch controller extension, bringing up the number of controllable switches to 16. In this case, only 8 of the multi-purpose inputs can be used.
The switch controller is equipped with an ESP32-S3 chip and communicate over WiFi.
The switch controller can run of a 15-24V power supply. In theory, it can run without a power supply and use the DCC in for power, but this does currently not work reliably yet until we fix an electrical issue.
The switch controllers have an expansion slot for our port extension, see below. It does not conflict with the switch controller extension.
The port extension can be plugged on top of the sensor controller or switch controller. It provides 8 signal connectors, each of them can connect up to 7 daisy-chained signals (or to connect other devices that require 5V, 3.3V and one output pin). It also provides 8 connectors for NFC readers, which could be used to identify passing trains.
We have signals, which we unortunately can not use unless someone can 3D-print the cases for us. They are Deutsche Bahn Ks-style signals with an optional tiny LED matrix for a Zs-style destionation display.