diff --git a/platformio.ini b/platformio.ini
index b32eea3..61412cd 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -28,6 +28,23 @@ lib_deps =
 lib_ignore =
     mbedtls
 
+[env:nrf52840_mdk]
+platform = nordicnrf52
+board = nrf52840_mdk
+framework = zephyr
+monitor_speed = 115200
+test_ignore = test_desktop
+build_flags = 
+    -Iinclude/tls_config
+    # For testing: -DUNITY_EXCLUDE_SETJMP_H=1
+    -DEN_INCLUDE_ZEPHYR_DEPS=1
+    -DEN_INIT_MBEDTLS_ENTROPY=0
+    -DCOVID_MEASURE_PERFORMANCE=0   # Used to measure device performance
+lib_deps =
+    prathje/exposure-notification @ ^0.1
+lib_ignore =
+    mbedtls
+
 [env:desktop]
 platform = native
 test_ignore = test_embedded
diff --git a/zephyr/nrf52840_mdk.overlay b/zephyr/nrf52840_mdk.overlay
new file mode 100644
index 0000000..b9f3b97
--- /dev/null
+++ b/zephyr/nrf52840_mdk.overlay
@@ -0,0 +1,14 @@
+
+/ {
+	buttons {
+		compatible = "gpio-keys";
+		button1: button_1 {
+			gpios = <&gpio0 15 (GPIO_PULL_DOWN | GPIO_ACTIVE_HIGH)>;
+			label = "button1";
+		};
+	};
+	aliases {
+		sw1 = &button1;
+	};
+
+};