As you can see in the schematic all three TC74 sensors have their SDA and SCL pins connected in series to pin A4 and A5 on the Arduino board. The two 4.7K pull-up resistors must be used when using I2C ...

He wanted to do a little more with the equipment so he ditched the watch and built an Arduino-based heart rate monitor. He’s still using the chest strap and was happy to find that SparkFun sells ...

This article describes the construction of a simple Arduino RFID Access control DIY (Do It Yourself) Project using Arduino UNO and a RFID reader module (EM-18) to control an LED and a Relay. Circuit ...