Table 5.

Mean RSSI values joined for two BT communication modules measured in three experimental conditions.

BT Module (A)/Condition	OD&NS	CD&NS	CD&RS
HC-06 (5 V, BT 2.0)	−60 dBm	−90 dBm	−91 dBm
MLT-BT05 (3.3 V, BT 4.1)	−86 dBm	−92 dBm	−94 dBm

^(A) PPG-EP and PPG-PS1 prototypes consist of the same BT module HC-06; PPG-BLE includes the MLT-BT05 module.