How to lock eth into a smart contract for a certain amount of time?

Question

Is there any way to send an amount of eth to a smart contract address setting a delay time before the sender address could redeem?

Answer 1

The code below allows several users to lock ether in a smart contract. Each subject can withdraw the ether that he/she deposited after a certain amount of time (in this example 1 day).

pragma solidity ^0.5.1;

contract timeLock {

    uint256 lockTime = 1 days;

    struct locked{
        uint256 expire;
        uint256 amount;
    }

    mapping(address => locked) users;

    function lockEther() public payable {
        require(msg.value>0);
        locked storage userInfo = users[msg.sender];
        userInfo.expire = block.timestamp + lockTime;
        userInfo.amount = msg.value;
    }

    function withdraw() public {
        require(block.timestamp>=users[msg.sender].expire);
        locked storage userInfo = users[msg.sender];
        uint256 value = userInfo.amount;
        userInfo.expire = 0;
        userInfo.amount = 0;
        msg.sender.transfer(value);
    }



}

Hope this helps.

Answer 2

OpenZeppelin has a TokenTimelock contract and you could use a similar idea for Ether. https://docs.openzeppelin.com/contracts/2.x/api/token/erc20#TokenTimelock