diff --git a/README.md b/README.md
new file mode 100644
index 0000000..5656d4a
--- /dev/null
+++ b/README.md
@@ -0,0 +1,74 @@
+# arduino-nix
+
+A flake that allows building an `arduino-cli` environment with certain packages and libraries pre-installed.
+
+## Example
+
+You need to provide a package index and library index to use `arduino-nix`. You can find some at [arduino-indexes](https://github.com/bouk/arduino-indexes).
+
+Alternatively, you can download them at https://downloads.arduino.cc/packages/package_index.json and https://downloads.arduino.cc/libraries/library_index.json
+
+From the indexes you create overlays which then make the Arduino packages and libraries available for the wrapArduinoCLI function provided by this flake.
+
+```nix
+{
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+    arduino-nix.url = "github:bouk/arduino-nix";
+    arduino-library-index = {
+      url = "github:bouk/arduino-indexes/library_index";
+      flake = false;
+    };
+    arduino-package-index = {
+      url = "github:bouk/arduino-indexes/package_index";
+      flake = false;
+    };
+    arduino-package-rp2040-index = {
+      url = "github:bouk/arduino-indexes/package_rp2040_index";
+      flake = false;
+    };
+  };
+
+  outputs = {
+    self,
+    nixpkgs,
+    flake-utils,
+    arduino-nix,
+    arduino-package-index,
+    arduino-package-rp2040-index,
+    arduino-library-index,
+    ...
+  }@attrs:
+  let
+    overlays = [
+      (arduino-nix.overlay)
+      (arduino-nix.mkArduinoPackageOverlay (arduino-package-index + "/package_index.json"))
+      (arduino-nix.mkArduinoPackageOverlay (arduino-package-rp2040-index + "/package_rp2040_index.json"))
+      (arduino-nix.mkArduinoLibraryOverlay (arduino-library-index + "/library_index.json"))
+    ];
+  in
+  (flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = (import nixpkgs) {
+          inherit system overlays;
+        };
+      in rec {
+        packages.arduino-cli = pkgs.wrapArduinoCLI {
+          libraries = with pkgs.arduinoLibraries; [
+            (arduino-nix.latestVersion ADS1X15)
+            (arduino-nix.latestVersion Ethernet_Generic)
+            (arduino-nix.latestVersion SCL3300)
+            (arduino-nix.latestVersion TMCStepper)
+            (arduino-nix.latestVersion pkgs.arduinoLibraries."Adafruit PWM Servo Driver Library")
+          ];
+
+          packages = with pkgs.arduinoPackages; [
+            platforms.arduino.avr."1.6.23"
+            platforms.rp2040.rp2040."2.3.3"
+          ];
+        };
+      }
+    ));
+}
+```
diff --git a/lib.nix b/lib.nix
index 93e1daf..562153a 100644
--- a/lib.nix
+++ b/lib.nix
@@ -4,6 +4,21 @@ let
 in
 with builtins; rec {
   latestVersion = attrs: (builtins.head (builtins.sort (a: b: (builtins.compareVersions a.version b.version) == 1) (builtins.attrValues (builtins.mapAttrs (version: value: { inherit version value; }) attrs)))).value;
+
+  # From tools.go in arduino-cli
+  #	regexpLinuxArm   = regexp.MustCompile("arm.*-linux-gnueabihf")
+  #	regexpLinuxArm64 = regexp.MustCompile("(aarch64|arm64)-linux-gnu")
+  #	regexpLinux64    = regexp.MustCompile("x86_64-.*linux-gnu")
+  #	regexpLinux32    = regexp.MustCompile("i[3456]86-.*linux-gnu")
+  #	regexpWindows32  = regexp.MustCompile("i[3456]86-.*(mingw32|cygwin)")
+  #	regexpWindows64  = regexp.MustCompile("(amd64|x86_64)-.*(mingw32|cygwin)")
+  #	regexpMac64      = regexp.MustCompile("x86_64-apple-darwin.*")
+  #	regexpMac32      = regexp.MustCompile("i[3456]86-apple-darwin.*")
+  #	regexpMacArm64   = regexp.MustCompile("arm64-apple-darwin.*")
+  #	regexpFreeBSDArm = regexp.MustCompile("arm.*-freebsd[0-9]*")
+  #	regexpFreeBSD32  = regexp.MustCompile("i?[3456]86-freebsd[0-9]*")
+  #	regexpFreeBSD64  = regexp.MustCompile("amd64-freebsd[0-9]*")
+
   selectSystem = system: systems:
     if system == "aarch64-darwin" then
       alt (lib.findFirst ({host, ...}: (match "arm64-apple-darwin.*" host) != null) null systems) (selectSystem "x86_64-darwin" systems)
diff --git a/packages.nix b/packages.nix
index 691fa76..b284a96 100644
--- a/packages.nix
+++ b/packages.nix
@@ -1,17 +1,3 @@
-# From tools.go in arduino-cli
-#	regexpLinuxArm   = regexp.MustCompile("arm.*-linux-gnueabihf")
-#	regexpLinuxArm64 = regexp.MustCompile("(aarch64|arm64)-linux-gnu")
-#	regexpLinux64    = regexp.MustCompile("x86_64-.*linux-gnu")
-#	regexpLinux32    = regexp.MustCompile("i[3456]86-.*linux-gnu")
-#	regexpWindows32  = regexp.MustCompile("i[3456]86-.*(mingw32|cygwin)")
-#	regexpWindows64  = regexp.MustCompile("(amd64|x86_64)-.*(mingw32|cygwin)")
-#	regexpMac64      = regexp.MustCompile("x86_64-apple-darwin.*")
-#	regexpMac32      = regexp.MustCompile("i[3456]86-apple-darwin.*")
-#	regexpMacArm64   = regexp.MustCompile("arm64-apple-darwin.*")
-#	regexpFreeBSDArm = regexp.MustCompile("arm.*-freebsd[0-9]*")
-#	regexpFreeBSD32  = regexp.MustCompile("i?[3456]86-freebsd[0-9]*")
-#	regexpFreeBSD64  = regexp.MustCompile("amd64-freebsd[0-9]*")
-
 { fetchzip, stdenv, lib, packageIndex, pkgsBuildHost, pkgs, arduinoPackages }:
 
 with builtins;