I find myself scratching my head as I know there are audit reports for the site collections, which is good, and I know there are third-party applications that can collate the audit data and present it nicely, but I want to collate all the data from each site collection and store it in a single csv file every 60 minutes... or even better, 'simply' store all SharePoint audit data(view, download, create, delete, etc) in a custom event log file (similar to system or application or setup for Windows Logs).

Is there anyone out there that uses custom code to do either of the above?
or do you have any advice? it's not that I don't want to use third-party solutions, I'm just looking for a way to capture it using the simplest possible method.

Thank you for your help.

**UPDATE**(source at bottom of scipt)<br>
So I found this site and script and its almost perfect. what its missing is the direct URL to the library/list/document that I was hoping for and the audit comments are missing specifics of the audit event (like what document was viewed/ updated for example) the export functionality is great, but I need to figure out a way to specify times...

have a look below and give it a try, any improvements you make, please share

Thanks again

    Add-PSSnapin Microsoft.SharePoint.PowerShell

	$tabName = "AuditLog"

	#Create Table object
	$table = New-Object system.Data.DataTable "$TabName"

	#Define Columns
	$col1 = New-Object system.Data.DataColumn SiteUrl, ([string])
	$col2 = New-Object system.Data.DataColumn SiteID, ([string])
	$col3 = New-Object system.Data.DataColumn ItemName, ([string])
	$col4 = New-Object system.Data.DataColumn ItemType, ([string])
	$col5 = New-Object system.Data.DataColumn UserID, ([string])
	$col6 = New-Object system.Data.DataColumn UserName, ([string])
	$col7 = New-Object system.Data.DataColumn Occurred, ([DateTime])
	$col8 = New-Object system.Data.DataColumn Event, ([string])
	$col9 = New-Object system.Data.DataColumn Description, ([string])
	$col10 = New-Object system.Data.DataColumn EventSource, ([string])
	$col11 = New-Object system.Data.DataColumn SourceName, ([string])
	$col12 = New-Object system.Data.DataColumn EventData, ([string])
	$col13 = New-Object system.Data.DataColumn MachineName, ([string])
	$col14 = New-Object system.Data.DataColumn MachineIP, ([string])

	#Add the Columns
	$table.columns.add($col1)
	$table.columns.add($col2)
	$table.columns.add($col3)
	$table.columns.add($col4)
	$table.columns.add($col5)
	$table.columns.add($col6)
	$table.columns.add($col7)
	$table.columns.add($col8)
	$table.columns.add($col9)
	$table.columns.add($col10)
	$table.columns.add($col11)
	$table.columns.add($col12)
	$table.columns.add($col13)
	$table.columns.add($col14)

	# =================================================== 
	# =================================================== 
	# =================================================== 

	$site = Get-SPSite -Identity 'http://spsql/'
    #$web = Get-SPWeb -Site $site
	$wssQuery = New-Object -TypeName Microsoft.SharePoint.SPAuditQuery($site)
	$auditCol = $site.Audit.GetEntries($wssQuery)
	$root = $site.RootWeb

	for($i = 0; $i -le ($auditCol.Count) - 1; $i ++)
	{
		 #Get the Entry Item from the Collection
		 $entry = $auditCol.item($i)
		 #Create a row
		 $row = $table.NewRow()

			   #find the Current UserName
			   foreach($User in $root.SiteUsers)
	{
					if($entry.UserId -eq $User.Id)
	{
						 $UserName = $User.UserLogin
	}
	}
			   #find the Item Name
			   foreach($List in $root.Lists)
	{
					if($entry.ItemId -eq $List.Id)
	{
						 $ItemName = $List.Title
	}
	}
	#Define Description for the Event Property
		 switch($entry.Event)
	{
	AuditMaskChange { $eventName = "The audit flags are changed for the audited object."}
	ChildDelete { $eventName = "A child of the audited object is deleted." }
	ChildMove { $eventName = "A child of the audited object is moved." }
	CheckIn { $eventName = "A document is checked in." }
    'Copy' { $ eventName = "The audited item is copied." }
	Delete { $eventName = "The audited object is deleted." }
	EventsDeleted { $eventName = "Some audit entries are deleted from SharePoint database." }
	'Move' { $eventName = "The audited object is moved." }
	Search { $eventName = "The audited object is searched." }
	SecGroupCreate { $eventName = "A group is created for the site collection. (This action also generates an Update event.See below.)" }
	SecGroupDelete { $eventName = "A group on the site collection is deleted." }
	SecGroupMemberAdd { $eventName = "A user is added to a group." }
	SecGroupMemberDelete { $eventName = "A user is removed from a group." }
	SecRoleBindBreakInherit { $eventName = "A subsite's inheritance of permission level definitions (that is, role definitions) is defined." }
	SecRoleBindInherit { $eventName = "A subsite is set to inherit permission level definitions (that is, role definitions) from its parent." }
	SecRoleBindUpdate { $eventName = "The permissions of a user or group for the audited object are changed." }
	SecRoleDefCreate { $eventName = "A new permission level (a combination of permissions that are given to people holding a particular role for the site collection) is created." }
	SecRoleDefDelete { $eventName = "A permission level (a combination of permissions that are given to people holding a particular role for the site collection) is deleted." }
	SecRoleDefModify { $eventName = "A permission level (a combination of permissions that are given to people holding a particular role for the site collection) is modified." }
	Update { $eventName = "An existing object is updated." }
	CheckOut { $eventName = "A document is checked Out." }
	View { $eventName = "Viewing of the object by a user." }
	ProfileChange { $eventName = "Change in a profile that is associated with the object." }
	SchemaChange { $eventName = "Change in the schema of the object." }
	Undelete { $eventName = "Restoration of an object from the Recycle Bin." }
	Workflow { $eventName = "Access of the object as part of a workflow." }
	FileFragmentWrite { $eventName = "A File Fragment has been written for the file." }
	Custom { $eventName = "Custom action or event." }
	default { $eventName = "The Event could not be determined." }
	}
		 #Enter data in the row
		 $row.SiteUrl = $web.Url
		 #$row.SiteID = $entry.SiteID
		 $row.ItemName = $ItemName
		 $row.ItemType = $entry.ItemType
		 #$row.UserID = $entry.UserID
		 $row.UserName = $UserName
		 $row.Occurred = $entry.Occurred
		 $row.Event = $entry.Event
		 $row.Description = $eventname
		 $row.EventSource = $entry.EventSource
		 $row.SourceName = $entry.SourceName
		 $row.EventData = $entry.EventData
		 $row.MachineName = $entry.MachineName
		 $row.MachineIP = $entry.MachineIP

		 #Add the row to the table
		 $table.Rows.Add($row)
	}

	# =================================================== 
	# =================================================== 
	# =================================================== 

		 #Display the table (Optional)
		 $table | format-table -AutoSize

	$date = get-date -format "dd-MM-yyyy HH-MM"
	$sDtae = [string] $date
	$FileName = "AuditLogReport_For_" + $sDtae
	
    #Export the CSV File to Folder Destination
    $tabCsv = $table | export-csv C:\$FileName.csv -noType

source: http://shokochino-sharepointexperience.blogspot.com/2013/05/create-auditing-reports-in-sharepoint.html?m=1