# Getting Started

## Prerequisites

- Elixir 1.17 or later
- Erlang/OTP 26 or later
- A DJI Tello or Tello EDU (optional -- the simulator works without hardware)

## Installation

Add `ex_drone` to your dependencies:

```elixir
def deps do
  [
    {:ex_drone, "~> 0.3.0"}
  ]
end
```

Then run:

```shell
mix deps.get
```

## Your First Flight (Simulator)

The simulator requires no hardware and is the best way to learn ex_drone:

```elixir
{:ok, drone} = Drone.connect(:sim, name: :my_drone)
Drone.connect_sdk(drone)
Drone.takeoff(drone)
Drone.move(drone, :up, 40)
Drone.move(drone, :forward, 100)
Drone.rotate(drone, :cw, 90)
Drone.land(drone)
Drone.disconnect(drone)
```

## Querying State

```elixir
{:ok, drone} = Drone.connect(:sim, name: :test)
Drone.connect_sdk(drone)

{:ok, battery} = Drone.query(drone, :battery)
{:ok, telemetry} = Drone.telemetry(drone)
```

## Safety Policies

Configure safety limits at connection time:

```elixir
# Indoor mode (tight limits)
{:ok, drone} = Drone.connect(:sim, name: :indoor, safety: [indoor: true])

# Custom limits
{:ok, drone} = Drone.connect(:sim, name: :custom,
  safety: [
    max_altitude_cm: 200,
    max_distance_cm: 500,
    min_battery_percent: 20,
    prop_guards: true
  ]
)

# Dry-run mode (validate without flying)
{:ok, drone} = Drone.connect(:sim, name: :dry, safety: [dry_run: true])
```

## Emergency Stop

```elixir
Drone.emergency(drone)  # Bypasses all safety checks, stops motors immediately
```

## Connecting to a Tello

1. Power on your Tello drone
2. Connect to the Tello's Wi-Fi network (SSID: `TELLO-XXXXXX`)
3. Connect with ex_drone:

```elixir
{:ok, drone} = Drone.connect(:tello, name: :tello_1)
Drone.connect_sdk(drone)
Drone.takeoff(drone)
```

Always test your missions in the simulator first.

## Connecting to a Crazyflie (mock)

No hardware required — use the in-process mock transport:

```elixir
{:ok, drone} =
  Drone.connect(:crazyflie,
    name: :cf_1,
    uri: "mock://ready",
    positioning: :flow
  )

Drone.connect_sdk(drone)
Drone.takeoff(drone)
Drone.move(drone, :forward, 50)
Drone.land(drone)
Drone.disconnect(drone)
```

For Crazyradio hardware, pass a `usb_backend` implementing
`Drone.Adapters.Crazyflie.USB`. See the [Crazyflie guide](crazyflie.md).

## Next Steps

- [Safety](safety.md) — policies, geofencing, allowlists
- [Simulator](simulator.md) — failure injection and initial pose
- [Crazyflie](crazyflie.md) — radio URIs, logging, SafeLink, readiness
- [Swarms](swarm.md) and [Formations](formations.md) — multi-drone coordination
- [Further Reading](further_reading.md) — platforms, planners, and research