const-ness is more essential than constexpr-ness here
Both could be used simultaneously but there would be little benefit
in this case.
using namespace sensesp;
-constexpr unsigned int read_delay = 500;
+const unsigned int read_delay = 500;
-constexpr uint8_t input_pin1 = 15;
-constexpr uint8_t output_pin1 = 18;
-constexpr uint8_t input_pin2 = 13;
-constexpr uint8_t output_pin2 = 21;
+const uint8_t input_pin1 = 15;
+const uint8_t output_pin1 = 18;
+const uint8_t input_pin2 = 13;
+const uint8_t output_pin2 = 21;
// This is a sample program to demonstrate how to instantiate a
// SensESPMinimalApp application and only enable some required components
