diff --git a/externals/rules/cynthion.nix b/externals/rules/cynthion.nix
new file mode 100644
index 0000000..c1321f3
--- /dev/null
+++ b/externals/rules/cynthion.nix
@@ -0,0 +1,7 @@
+{ writeTextFile }:
+
+writeTextFile {
+  name = "cynthion-udev-rules";
+  text = builtins.readFile ./cynthion.rules;
+  destination = "/etc/udev/rules.d/54-cynthion.rules";
+}
diff --git a/externals/rules/cynthion.rules b/externals/rules/cynthion.rules
new file mode 100644
index 0000000..6da1054
--- /dev/null
+++ b/externals/rules/cynthion.rules
@@ -0,0 +1,16 @@
+# Configures Linux to allow access to Cynthion hardware for anyone logged into the physical terminal.
+#
+#     # install udev rules
+#     sudo cp 54-cynthion.rules /etc/udev/rules.d
+#
+#     # reload udev rules
+#     sudo udevadm control --reload
+#
+#     # apply udev rules to any devices that are already plugged in
+#     sudo udevadm trigger
+
+SUBSYSTEM=="usb", ATTR{idVendor}=="1d50", ATTR{idProduct}=="615b", SYMLINK+="cynthion-%k", TAG+="uaccess"
+SUBSYSTEM=="usb", ATTR{idVendor}=="1d50", ATTR{idProduct}=="615c", SYMLINK+="cynthion-apollo-%k", TAG+="uaccess"
+
+SUBSYSTEM=="usb", ATTR{idVendor}=="1209", ATTR{idProduct}=="000a", SYMLINK+="cynthion-test-%k", TAG+="uaccess"
+SUBSYSTEM=="usb", ATTR{idVendor}=="1209", ATTR{idProduct}=="000e", SYMLINK+="cynthion-example-%k", TAG+="uaccess"
diff --git a/sets/hardware.nix b/sets/hardware.nix
index 8fd3465..b25b411 100644
--- a/sets/hardware.nix
+++ b/sets/hardware.nix
@@ -2,6 +2,7 @@
 {
   services.udev.packages = with pkgs; [
     (callPackage ../externals/rules/adafruit.nix { })
+    (callPackage ../externals/rules/cynthion.nix { })
     (callPackage ../externals/rules/limesuite.nix { })
     glasgow
     libsigrok
@@ -10,6 +11,7 @@
   ];
 
   environment.systemPackages = with pkgs; [
+    cynthion
     glasgow
     jlink
     kicad