Backtimer in smart contract

Question

I want to add a thing to my contract where every 10minutes all the ETH from a contract is sent to my wallet. I don't know how to do it. Any help appreciated

Answer 1

There is no way to have timers in smart contracts. You'll have to write a script off-chain that sends a transaction to the contract telling it to withdraw. Alternatively you could just forward all payments to the contract to your address.

Answer 2

There is a way to do this.

The contract can get the time directly but cannot execute itself.

You can use services like Chronos, which allows you to schedule calls to your contract in a simple way. You will find examples of how to do exactly what you are asking for here look at the examples. This can be used on Rinkeby for testing. You can, for instance, request your contract to be called every N blocks.

Others services are available as well, like Oraclize and ethereum alarm clock

Example of how to do what you asked using in Chronos (contract balance should be enough to pay for gas or you can pre-charge you contract address using the functions of Chronos, you can always claim back what you don't use):

pragma solidity ^0.4.20; 


contract _Chronos {
    function registerCall(address contractAddress, uint256 callOnBlock, uint256 gasAmount) public returns (uint256);
    function clientWithdraw(uint256 value) public;
    function clientFunding(address contractAddress) public payable;

}

contract Client {
    function setCallrequest(uint256 blockNumber, uint256 gasAmount) public;
    function callBack() public;
    function withdrawFromChronos(uint value) public;
    function getDepositsFromChronos() public payable;
}



contract YourContract is Client {
    address public chronosAddress;
    address public admin;

    function YourContract() public {
        chronosAddress = address(0x4896FE22970B06b778592F9d56F7003799E7400f);
        admin = msg.sender;
    }




    function setCallrequest(uint256 blockNumber, uint256 gasAmount) public {
        _Chronos ChronosInstance = _Chronos(chronosAddress);
        uint256 costs = ChronosInstance.registerCall(address(this), blockNumber, gasAmount);
        require(address(this).balance >= costs);
        ChronosInstance.clientFunding.value(costs)(address(this));
    }


    function callBack() public {
        setCallrequest(block.number + 40, 200000); // 40 indicated how many blocks to wait to receive the call, 40 blocks * 15sec/block = 600 sec = 10 min

        admin.transfer(this.balance); // you may want to leave some ether in your contract to pay for the next call. The gas used is small but is not zero, in this example 200000 gas is passed. If this is not consumed the contract will save it and you can withdraw what you do not use. if the gas you pass is not enough the call is not executed. 
    }



    function () public payable {}



}

Disclaimer: I wrote the code for Chronos.

Let me know if this works for you. hope it helps