Rolling Line now has a bunch of props and tools which make circuitry and automation possible.
You can use automation props (like levers and doors) to make simple or complex interactions. Things like turning on a light when a lever is pulled, opening doors when a train passes over a trigger, playing a sound when the player stands in a set location or opening locked doors with keys.

The circuity tools (like wires and logic gates) can be used to make much more advanced creations. These can be simple circuits like making lights enable based on whether a train is parked in a certain spot, or incredibly advanced logic like giant circuit boards to replicate calculators!

This guide will explain how to make use of these new automation & circuitry props.
You can find them in the drawer "Room -> Automation":



And in the drawer "Room -> Electronics":

The main part of the system to understand is how these objects interact with each other.
You can link automation props together either with physical wires, or passwords.

Using a password you can send a "pulse" from one prop to another, like clicking a lever and opening a door. Think of these passwords as like sending a trigger message, it acts as a single pulse and has no true/false state.
If you just want to make simple interactions (like turning lights on/off, or interacting with doors) then passwords is all you need. They are much more simple, and dont require any use of wires.

Here is an example of a lever linked to a light using a password (when the lever is clicked, it sends a "pulse" to the light, which then toggles on/off):



Wires allow for much more detailed circuits. Wires need to be manually attached from one prop to another using the "electrical wire tool" found in the "Room -> electronics" drawer.
If you are using wires then no passwords are necessary, the wires will do the "transmitting" instead of passwords.
Wires allow for both "pulses" (like what passwords do) as well as true/false states.
This means a wire can either be on or off, and stay that way. This is very useful for more advanced circuitry since it behaves much more like real electricity.

Here is an example of a wire sending a pulse (which behaves just like using a password):



And here is an example of a light using a true/false state (the lever is toggled to either be on/off, which then sets the light to be on/off as well):



Both of these systems will be explained in more detail during this guide!

A core aspect of this automation system is the use of passwords.

When you place down one of these automation props you will have the option to set a password.
All objects that share the same password will be linked to each other, which means that a trigger (like clicking a lever) will open any doors that share the same password.

Multiple objects can all share the same password, so one lever can open multiple doors and multiple levers can open the same door.

For a simple example, lets make a system where the player can stand on a trigger to open a pair of locked doors in front of them:

1 - place down two of the iron door props (these can only be opened using password activation, they cannot be clicked by the player).

2- place down a "player trigger activator"



3 - open the options editing menu on each of the doors (press Q for the left-hand hover option). From here you can set the password for each door prop. Set both of the doors passwords to "doors":



4 - Edit the player trigger activator and set the password to "doors", so that this trigger will activate the two doors which share the same password when stood on by the player.

You can also change the "radius" value to set how close the player needs to be to the button for it to trigger.
A value like "0.1" for the radius is good. Please note that the trigger is activated by the position of the players head, not their feet, so make sure the radius is large enough to include their head.



5 - That's everything! Choose "apply edits" on the edit tool to disable editing. You can now go into miniature mode and try standing on the button:

Another set of props you can use are keys & locked doors.
These work similarly to the password-activated doors in the first example, but you can only use a physical key object to open them.

Here is an example of how to make a working key & door:

1 - place a locked door (the one with the padlock) on the ground, as well as a key:



2 - Just like in the previous example, you will need to set the password for both the key and the door to be the same.
You can open the password edit menu even when in miniature mode (if you have miniature mode interaction enabled in the "gameplay -> miniature mode options" menu).



Once you have done this, simply hold the key in your hand and then click on the padlock, if the passwords match then the lock will be removed and the door can be opened:



Please note that the key prop works in a special way, where it can only be placed on the ground while in large scale. Meanwhile in miniature scale it will act as a usable key when held. This means you can only click-to-open doors while in miniature mode, and can only place the key down on your map in large scale mode.
Once placed on the ground, keys can also be cloned at any time, regardless of whether editing is enabled or not.

Here is an example map which makes use of keys and doors:

https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3021839949

Now things get a bit more complex! (and more interesting).

You can use the "remote trigger activator" prop to essentially "click" on any objects near it when activated.
These use the same password system as doors, but when the password is activated (e.g. by a lever or button) it will make the remote trigger activator perform it's "click" on all nearby objects.

This "click" that it does is just like the player clicking on an object, so it can do things like toggling a light switch on/off, decoupling a wagon, switching a turnout, etc.
It can even be used to click on other levers! Which can be used to create much more complex logic and circuits.

But for now let's just look at some basic examples.
Here is a quick example of how to use a remote trigger activator to toggle a light on/off when the player clicks a lever.

1 - place down a light source (anything with a button that the player can click). Then right next to the button place down a remote trigger activator. Then nearby place down a lever:



2 - set the password for both the lever and the remote trigger activator to the same value, and make sure the "radius" for the remote trigger activator is the right size so that it overlaps the button control on the light:



(notice how the control button for the light is within the remote trigger activators range)



3 - If everything is set up correctly, clicking the lever will cause the remote trigger activator to "trigger" and click the control button on the light:




Lots of automation props also have a "delay" setting, you can use this to add a delay (in seconds) between when the object is triggered, and when it acts on that trigger.

For example, you can make a lever only send out a signal a set time after it is used, or make a remote trigger activator only perform its "click" on nearby objects after a delay.

You can use these delays to make some interesting effects, like activating lights one-by-one from a single lever click:



Or you could even make an infinite loop of lights which activate each other:




Remote trigger activators can be used for some very complex behaviour if you get creative with them, since they can activate other levers, and therefore be used to create lots of kinds of advanced logic.
Some things to consider about remote trigger activators behaviour are:

• They will not "click" on the object that activated them, so if you use a remote trigger activator to click on another remote trigger activator, it will not activate the previous one and create an infinite loop.
  
• Remote trigger activators cannot "click" on any other remote trigger activators, if you want to trigger another one then you can use a lever instead, which activates another remote trigger activator.
  
• When a remote trigger activator is used, a record is kept of every object that has been "clicked" by it, and no objects will be clicked twice. It doesn't matter how many activators are used, no object will be clicked more than once. This is to prevent infinite loops.
  
• The above rule only applies when there are no delays involved. If you add a delay then all objects will be able to be clicked on again. This means you need to be careful when using delays since it is completely possible to create an infinite loop!
  
• You can enable "allow cloning" in the options menu to allow remote trigger activators to clone props/trains/track by clicking on them. This can be used for spawning in objects remotely, but be careful as this can very easily cause chaos by cloning unwanted props. Make sure only the props you want to clone are editable!
  
• Remote trigger activators can't be used to click on confirmation popup boxes in menus. This is to prevent things like deleting save files, exiting the game, etc. You can still use them to click on any other menu buttons though, which can be used for some very interesting effects (like changing the weather/time when a custom lever is clicked).

By default, the light source and particle source props do not have a clickable button, but you can easily enable this in the options popup menu (press Q for the left-hand context option).

Once the particle/light source has a visible button object, you can use a remote trigger activator to click on it and control it.




Using prop modding you can create some very interesting effects! Since prop mods can do things like playing sounds, lights, animations and particles on click, you can combine this with these automation tools to make all kinds of cool things happen!

For example, you could make a prop mod play an animation when clicked, and link this up with a lever and remote trigger activator to make a situation where the player can click a lever to play a custom animation.
Or you could make a mock explosion effect by playing a particle effect, flash of light, and a sound effect when clicked.

Another useful tool in the set of automation props is the range extender.

Range extenders are used to repeat a remote trigger activators "click" effect range further. Meaning that if a remote trigger activator clicks on a range extender, then the range extender will repeat the same "click" effect within its range.

Like in this example, the remote trigger activator on the left tries to "click" the range extender, and the range extender repeats the "click" so that the lever on the right is clicked:





You can also toggle whether the range extender is active or not, it will only relay the click effect of nearby remote trigger activators if it is enabled, otherwise it will do nothing.
This can be very useful for having control over whether a circuit is linked or disconnected, e.g. you can use a range extender to either block or allow a trigger message to pass from one prop to another.

Please note that remote trigger activators cannot click on the range extender on/off lever, this can only be toggled by the player manually or set using the password.



Here is an example of how to use a range extender to setup a circuit that only allows a particle system to be controlled if a mock "power generator" is switched on.
The power generator is just for visual purposes, it doesn't actually do anything, this is just to show a scenario where you could use a system like this.



In this example, the lever on the generator shares a password with the range extender (green boxes). This means that when you click the lever to "activate" the generator, it will enable the range extender and allow the signal to pass through.

The orange boxes also share a password, so that when you click the lever on the bottom left the remote trigger activator in the middle is activated, which then "clicks" on the range extender.

If the range extender is enabled, then it will relay the signal on to the next lever (the red box) which then triggers the remote trigger activator on the right next to the particle system.

Here is what the system looks like in motion:
(note the lever on the left being repeatedly clicked, then the lever on the generator being clicked once, which breaks the connection in the circuit)



While this is all quite complex to explain, I recommend just testing out the range extenders yourself and see what you can make.

Here is a more complex example of how to use a mixture of range extenders, levers, doors and remote trigger activators to make a puzzle map:
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3021340468

Some other more specific tools are:




You can use this prop to teleport the player to its location when activated.
These can be "activated" either by clicking on them (which can be done with a remote trigger activator) or using their password, just like with doors. Clicking a lever/button that shares the same password as a teleporter will activate the teleporter.




These triggers work in the same way as a lever, so that when they are "activated" they send out a trigger signal using the chosen password. Any objects that share the same password will be activated.


The player trigger will be activated when the player enters the chosen range of the object. You can use this to do things like opening doors when the player stands in front of them, or playing a sound when the player enters a new area.

You can use the "Allow repeat trigger" and "repeat trigger delay" options to change the behaviour of these triggers.
If "Allow repeat trigger" is disabled, then this trigger will only activate once when the player enters the range. It will only trigger again once the player has left the range and has re-entered the range.

meanwhile if you enable "Allow repeat trigger" then a trigger signal will be sent out repeatedly while the player is within range. The time between each repeated trigger can be set using the "repeat trigger delay" setting.
E.g. if you enable "Allow repeat trigger" and set "repeat trigger delay" to 1, then a trigger signal will be sent out every second while the player is within range.


This works in the same way as the player trigger, but it detects trains.
It will send out a trigger signal when a moving train (which is on tracks, not dropped) passes over it.



You can choose between a bunch of different control options:

• Once per wagon - trigger once per new wagon which passes the trigger
  
• Constant - trigger constantly while a train is crossing the trigger. Use the repeat trigger delay to control the time between signal triggers
  
• Start and end - Trigger once at the start of a whole train, and once again at the end
  
• Start only - Trigger once at the start of a whole train
  
• End only - Trigger once at the end after a whole train has passed

The "repeat trigger delay" will only have effect if you choose the "constant" detection mode option.


You can use this to display a popup message to the player when it is activated:

In addition to the simpler password method for transmitting messages between props, you can also connect up some components with physical wires.

Connecting two props with a wire behaves just like sharing a unique password, so connecting a lever to a teleporter will make the teleporter activate when the lever is clicked.



But wires allow for some more interesting behaviour!

Wires can also be either true/false (on/off) in addition to just sending out a single pulse.
For this to work you need an input source that creates a true/false signal instead of just a normal pulse signal.

For example, in the "Room -> Electronics" drawer you can find two different kinds of levers, one which sends out a pulse, and one which sends out a state (true/false):



If you use the state lever instead of the normal lever it will output a true/false state.
Link this up with an LED (light emmiting diode) to see this in action:



Other props can output a true/fase state if chosen.

For example, you can change the "trigger type" option for a player/train sensor to "on/off state" to make it output a true signal when the player/train is nearby, and a false signal when not.



When you set this up correctly, it will behave like this:



Most electrical props will behave differently based on whether they receive a pulse or a true/false state signal.

For example, when receiving a true/false state an LED will turn on/off, but if it receives a pulse it will toggle. So if it is on, it will turn off, and if it is off it will turn on.

In addition to the standard "Remote trigger activator" prop which clicks on nearby objects, there is also another version which can directly set the state of things like lights, particles, turnouts and signals based on a true/false wire input.

You can find this version in the "Room -> Electronics" drawer:



If given a true/false input state, then it will have the same effect on any surrounding objects, if it is given a pulse, then it will toggle between on/off.



These can be used to set the state of lights, particles and prop mods (animations, audio, etc).
They can also be used to control turnouts (straight = on, curve = off) and signals (green = on, red = off):

A more advanced feature you can make use of is logic gates.
In real-world electronics, logic gates are a way to create actual logic out of circuits, and is quite a deep topic that can be learnt about outside of Rolling Line:

https://www.khanacademy.org/computing/computers-and-internet/xcae6f4a7ff015e7d:computers/xcae6f4a7ff015e7d:logic-gates-and-circuits/a/logic-gates

The logic gate prop inside Rolling Line works in exactly the same way, it takes two inputs and creates an output, depending on the kind of logic gate you have chosen.

These logic gate types are:

• AND - triggers if both inputs are true
  
• OR - triggers if both or just one of the inputs are true
  
• XOR - Triggers if either one of the inputs is true, but not both
  
• NAND - The opposite of AND, triggers if none or one input is true
  
• NOR - The opposite of OR, triggers only if both inputs are false
  
• XNOR - The opposite of XOR, triggers when none or both inputs are true

For example, here is an AND gate, which will only output a signal if both of its inputs are true:



Logic gates can use both passwords (pulse signals) as well as true/false states.
E.g. if an AND gate receives pulses for both inputs on the same frame, it will output a pulse on that same frame.

Pulses and states can even be mixed, so one input might be a true/false state, while the other is a pulse.
E.g. an AND gate has one "true" input, and receives a pulse on the other input. This will send out a pulse on the output.

(note: when an LED, shown in this example, receives a pulse input it will toggle between on/off)




Logic gates can be taken to absolute extremes, since when you look deeply into digital electronics literally everything just breaks down into simple logic and electrical signals.

All the systems inside computers are made of just massive complex combinations of logic!

This means you can make some pretty insane stuff using these very simple base tools.
Adders[en.wikipedia.org] are a good example of how logic gates can be used to create something that has a very tangible input and output.

And yes, an amazing adder has already been made inside the Rolling Line circuit system! This was made by methylcyclo on the Discord server: