Echtzeit-Uhr

Realtime clock (RTC)

The robot requires a clock, so that it can start mowing automatically at certain time intervals (timer).

A realtime clock (RTC) returns current time (minute, hour) and date (day of week, day, month, year) - by the help of a battery the time continues to run even if the robot mower is switched off.

Additionally, the RTC module contains an EEPROM memory (non volatile memory) that can hold 4K of permanent user data.

Example: DS1307

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  ds1307

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  ds1307_schematics

Wiring

The RTC module is connected on the I2C bus of the Arduino Mega (in parallel with any other I2C modules).

 DS1307 Module SDA       — Arduino SDA Pin
 DS1307 Module SCL       — Arduino SCL Pin
 DS1307 Module VCC (+5V) — Arduino VCC (+5V)
 DS1307 Module GND       — Arduino GND

Note

If you experience communication problems when using multiple I2C modules on one I2C bus, it is recommended to reduce the length of the cables.

Timer

On the robot, several timers can be programmed (via Android pfodApp). For each timer, you can define a time interval ('time windows') for the desired days. As long as the actual time is within any time window, the robot can freely mow, charge, mow, charge etc.

Example:

Timer 1: 08:00 - 13:00 Monday, Thuesday, Wednesday

Timer 2: 14:00 - 16:00 every day

Timer 3: off

Timer 4: off