Real-Time Clock (RTC) Module
Background
The real-time clock (RTC) module is a very important component for data logging or scheduling things to happen at specific times of the day. As you know, the Arduino can keep track of the passage of time somewhat, but it really only knows the amount of time that has passed since it was last powered on. It has no idea of the time of year or even the time of day. The RTC allows us to know the particular date and time which can be necessary for certain projects. It has a coin cell battery which allows is to keep this time information across power cycles.
Hardware Description
Pinout
- GND - GND
- VCC – 5V
- SDA - I2C Data Pin. Connect to pin A4 on the Arduino Uno
- SCL - I2C Clock Pin. Connect to pin A5 on the Arduino Uno
- SQW - optional square-wave output
Software Description
See tutorial below.