> ## Documentation Index
> Fetch the complete documentation index at: https://docs.otim.com/llms.txt
> Use this file to discover all available pages before exploring further.

# At Time Intervals

For this example let's say you're terrible with remembering birthdays 😬 so you want to set up automatic on-chain reminders. Let's write a smart contract that will emit an event to remind you:

```solidity BirthdayReminder.sol theme={null}
// SPDX-License-Identifier: MIT OR Apache-2.0
pragma solidity ^0.8.26;

contract BirthdayReminder {

    event HappyBirthday(string name, uint8 month, uint8 day);

    function remind(string calldata name, uint8 month, uint8 day) external {
        emit HappyBirthday(name, month, day);
    }
}
```

Now, let's say you want to remind yourself about your friend Alice's birthday. Simply construct an Instruction that uses the `Call` Action to call your `BirthdayReminder` contract one week before Alice's birthday every year. Let's break this down:

* set `Instruction.action` to the address of the `Call` Action

* set `Instruction.arguments` to encoded calldata specifying:

  * set `Schedule.startAt` to a Unix timestamp that's about one week before Alice's next birthday

  * set `Schedule.interval` to one year in seconds

  * the address of your `BirthdayReminder` contract

  * the function selector for `remind`

  * the encoded arguments `name = "Alice"`, `month = 1`, and `day = 1`

These steps might look intimidating, but never fear, the Otim App will walk you through this process and abstract away these low-level details.

Now, activate this Instruction and you'll never forget Alice's birthday again!