diff --git a/i2c_qmp6988.h b/i2c_qmp6988.h
index 4118b12..f9fae28 100644
--- a/i2c_qmp6988.h
+++ b/i2c_qmp6988.h
@@ -8,6 +8,9 @@
 #include "NmeaXDR.h"
 #include "Nmea0183Msg.h"
 
+#define QMP6988_SLAVE_ADDRESS_L (0x70)
+#define QMP6988_SLAVE_ADDRESS_H (0x56)
+
 m5::unit::UnitQMP6988 i2c_qmp6988_sensor;
 bool i2c_qmp6988_found = false;
 
diff --git a/i2c_sht30.h b/i2c_sht30.h
index 238b81d..bf075ba 100644
--- a/i2c_sht30.h
+++ b/i2c_sht30.h
@@ -8,6 +8,8 @@
 #include "NmeaXDR.h"
 #include "Nmea0183Msg.h"
 
+#define SHT3X_I2C_ADDR 0x44
+
 m5::unit::UnitSHT30 i2c_sht30_sensor;
 bool i2c_sht30_found = false;