Elevator Project

Cross platform program for controlling m elevators over n floors, written in Elixir.

Program flow

Boot node
Ping other Nodes
IO_poller polls sensors and buttons

Button pushed?
  IO sends to the order module.
  Order auctions the order, all the elevators respond with their cost.
  Order accepted (for hall_up/hall_down one other elevator responds)?
    Send the order to the watchdogs.
    Update order_map with the corresponding elevator & order that won the auction.

Finished an order?
  Send a message to all order modules that you finished it.

Order in order_map?
  Calculate the cheapest order and send to elevator.

Order timed out?
  WatchDog sends the order back to auction.

Modules

Quick overview of existing modules and what they do.

Order

The brain of the elevator, sends orders to auction, updates the order map/sends orders to the watchdog, takes in new orders from IO and sends the next order to the elevator.

WatchDog

Used to handle orders that were not taken in time, sends these back to the Order module for redistribution.

Network

Keeps the elevator on the network by pinging the other elevators(if not in single elevator mode).

Lights

Retrieves the order map, and updates the lights accordingly.

Elevator

State machine for controlling the elevator. Is given a floor, and stops upon reaching that floor.

IO_poller

Polls the hardware buttons of the Driver module, and sends these to Elevator and Order accordingly.

Driver

For interfacing with the Simulator/elevator at the lab.

Supervision

All of these modules are implemented under the Main application, which starts the supervision tree in ElevProject.Supervisor.

How to run

IMPORTANT Assumes that you have both elixir and mix installed on your computer.

The entry point to the program is the elev_project/lib/main.ex file, or the elev_project/elevator_run.sh bash script. To change config parameters go to elev_project/config/config.exs.

IMPORTANT the network config needs to be changed based on IP, as we manually add them to the list of node_ips in elev_project/config/config.exs. Here the format is :"<elevator_number>@<node_ip>", which predetermines what IP is what elevator number. As long as one of the elevators have the correct IPs in its config it should work, due to elixir's Node module.

Navigate to the elev_project folder and run the following to get the dependencies.

mix deps.get

Run using the script (Linux only)

Install tmux

On ubuntu

sudo apt install tmux

Run the script

If you have tmux installed you can run the elevator_run.sh script.

To navigate the tmux windows visit tmux-cheat-sheet, to enable mouse clicking create ~/.tmux.conf and add the line set-window-option -g mouse on

With 1,2 or 3 total_number_of_elevators. Navigate to the elevator_run_sh script.

./elevator_run.sh <total_number_of_elevators>

Run using commands

First you need to run the simulators, these can be found in the simulator folder. Navigate to the Simulator folder. The simulator port has to match the elevator port. 6000, 6001, 6002 are examples of usable ports.

On Linux:

./SimElevatorServer --port <port>

On Windows:

SimElevatorServer.exe -port <port>

Then the elevators can seperately be started with the following commands from within the elev_project folder. Here the elevator_number starts at 1. The second elevator you start has the number 2 and so on. The total_number_of_elevators are 1-indexed as well.

Navigate to the elev_project folder.

On Linux/Windows:

iex -S mix
Main.run_elevator <port>, <elevator_number>, <total_number_of_elevators>

If it is not already running, start the Erlang port mapper daemon: On Linux:

epmd -daemon

On Windows, you need to locate epmd.exe and run it:

epmd.exe -daemon

Credits

GenStateMachine is used for FSM in the elevator.

Inspiration from Jostein Løwer's kokeplata in Network and IO_poller. And also for his Driver module.