diff --git a/.envrc b/.envrc
new file mode 100644
index 0000000..3550a30
--- /dev/null
+++ b/.envrc
@@ -0,0 +1 @@
+use flake
diff --git a/.gitignore b/.gitignore
index be8d07a..aa17621 100644
--- a/.gitignore
+++ b/.gitignore
@@ -150,3 +150,7 @@ dkms.conf
 *.out
 *.app
 
+# direnv cache
+.direnv
+# build directory
+build
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..643f237
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "pico-sdk"]
+	path = pico-sdk
+	url = https://github.com/raspberrypi/pico-sdk
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..a006037
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,22 @@
+cmake_minimum_required(VERSION 3.13...3.27)
+
+# initialize pico-sdk from submodule
+# note: this must happen before project()
+include(pico-sdk/pico_sdk_init.cmake)
+
+project(my_project)
+
+# initialize the Raspberry Pi Pico SDK
+set(PICO_BOARD, "pico")
+pico_sdk_init()
+
+# rest of your project
+add_executable(hello_world
+    hello_world.c
+)
+
+# Add pico_stdlib library which aggregates commonly used features
+target_link_libraries(hello_world pico_stdlib)
+
+# create map/bin/hex/uf2 file in addition to ELF.
+pico_add_extra_outputs(hello_world)
diff --git a/flake.lock b/flake.lock
new file mode 100644
index 0000000..5e6deae
--- /dev/null
+++ b/flake.lock
@@ -0,0 +1,64 @@
+{
+  "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": [
+          "systems"
+        ]
+      },
+      "locked": {
+        "lastModified": 1731533236,
+        "narHash": "sha256-l0KFg5HjrsfsO/JpG+r7fRrqm12kzFHyUHqHCVpMMbI=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "11707dc2f618dd54ca8739b309ec4fc024de578b",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1737255904,
+        "narHash": "sha256-r3fxHvh+M/mBgCZXOACzRFPsJdix2QSsKazb7VCXXo0=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "eacdab35066b0bb1c9413c96898e326b76398a81",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "ref": "release-24.11",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "flake-utils": "flake-utils",
+        "nixpkgs": "nixpkgs",
+        "systems": "systems"
+      }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
diff --git a/flake.nix b/flake.nix
new file mode 100644
index 0000000..252e013
--- /dev/null
+++ b/flake.nix
@@ -0,0 +1,33 @@
+{
+  description = "flake for rp2040 dev";
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/release-24.11";
+    systems.url = "github:nix-systems/default";
+    flake-utils = {
+      url = "github:numtide/flake-utils";
+      inputs.systems.follows = "systems";
+    };
+  };
+
+  outputs =
+    { nixpkgs, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          packages = with pkgs; [
+            gcc
+            cmake
+            gnumake
+            python312Full
+            gcc-arm-embedded
+            newlib
+          ];
+        };
+      }
+    );
+}
+
diff --git a/hello_world.c b/hello_world.c
new file mode 100644
index 0000000..e588b0e
--- /dev/null
+++ b/hello_world.c
@@ -0,0 +1,53 @@
+/**
+ * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include "pico/stdlib.h"
+
+// Pico W devices use a GPIO on the WIFI chip for the LED,
+// so when building for Pico W, CYW43_WL_GPIO_LED_PIN will be defined
+#ifdef CYW43_WL_GPIO_LED_PIN
+#include "pico/cyw43_arch.h"
+#endif
+
+#ifndef LED_DELAY_MS
+#define LED_DELAY_MS 250
+#endif
+
+// Perform initialisation
+int pico_led_init(void) {
+#if defined(PICO_DEFAULT_LED_PIN)
+    // A device like Pico that uses a GPIO for the LED will define PICO_DEFAULT_LED_PIN
+    // so we can use normal GPIO functionality to turn the led on and off
+    gpio_init(PICO_DEFAULT_LED_PIN);
+    gpio_set_dir(PICO_DEFAULT_LED_PIN, GPIO_OUT);
+    return PICO_OK;
+#elif defined(CYW43_WL_GPIO_LED_PIN)
+    // For Pico W devices we need to initialise the driver etc
+    return cyw43_arch_init();
+#endif
+}
+
+// Turn the led on or off
+void pico_set_led(bool led_on) {
+#if defined(PICO_DEFAULT_LED_PIN)
+    // Just set the GPIO on or off
+    gpio_put(PICO_DEFAULT_LED_PIN, led_on);
+#elif defined(CYW43_WL_GPIO_LED_PIN)
+    // Ask the wifi "driver" to set the GPIO on or off
+    cyw43_arch_gpio_put(CYW43_WL_GPIO_LED_PIN, led_on);
+#endif
+}
+
+int main() {
+    int rc = pico_led_init();
+    hard_assert(rc == PICO_OK);
+    while (true) {
+        pico_set_led(true);
+        sleep_ms(LED_DELAY_MS);
+        pico_set_led(false);
+        sleep_ms(LED_DELAY_MS);
+    }
+}
diff --git a/pico-sdk b/pico-sdk
new file mode 160000
index 0000000..95ea6ac
--- /dev/null
+++ b/pico-sdk
@@ -0,0 +1 @@
+Subproject commit 95ea6acad131124694cda1c162c52cd30e0aece0