diff --git a/lib/DnWiFiDoorLock/DnWiFiDoorLock/Arduino/Esp8266/EspAsyncWebServer/Http/ServoButtonController.h b/lib/DnWiFiDoorLock/DnWiFiDoorLock/Arduino/Esp8266/EspAsyncWebServer/Http/ServoButtonController.h
index 85f0f7b..f422e8f 100644
--- a/lib/DnWiFiDoorLock/DnWiFiDoorLock/Arduino/Esp8266/EspAsyncWebServer/Http/ServoButtonController.h
+++ b/lib/DnWiFiDoorLock/DnWiFiDoorLock/Arduino/Esp8266/EspAsyncWebServer/Http/ServoButtonController.h
@@ -529,9 +529,12 @@ namespace DnWiFiDoorLock::Arduino::Esp8266::EspAsyncWebServer::Http {
                 return tl::unexpected{PSTR("No required data given")};
             }
 
+            // todo: better conversion to int
+            //       `toInt()` uses `atol()` and has no error handling at all…
+            //       * https://en.cppreference.com/w/cpp/string/byte/strtol
+            //       * https://www.cppstories.com/2018/12/fromchars/
             const auto newPressingAngle = Servo::Angle::withDegrees(maybeNewPressingAngle->toInt());
             const auto newNotPressingAngle = Servo::Angle::withDegrees(maybeNewNotPressingAngle->toInt());
-            // todo: what if a negative number was given?
             const auto newMilliseconds = Button::PressingMilliseconds::create(maybeNewMilliseconds->toInt());
 
             if (!newPressingAngle) {
diff --git a/lib/DnWiFiDoorLock/DnWiFiDoorLock/Arduino/Servo/Button.h b/lib/DnWiFiDoorLock/DnWiFiDoorLock/Arduino/Servo/Button.h
index b741e24..7c04b9d 100644
--- a/lib/DnWiFiDoorLock/DnWiFiDoorLock/Arduino/Servo/Button.h
+++ b/lib/DnWiFiDoorLock/DnWiFiDoorLock/Arduino/Servo/Button.h
@@ -21,11 +21,12 @@ namespace DnWiFiDoorLock::Arduino::Servo {
     public:
         class PressingMilliseconds final {
         public:
+            template<typename T>
             static
             auto create(
-                uint32_t value
+                T value
             ) -> tl::expected<PressingMilliseconds, String> {
-                if (value == 0) {
+                if (value <= 0) {
                     return tl::unexpected{PSTR("Positive integer required")};
                 }