The following StackOverflow question and answer raises the issue and provides a solution for this feature.

Resample Time Series Data using Javascript and Mongodb

In addition of creating a bucket with predefined boundaries ($bucket), or one with autogenerated boundaries ($bucketAuto), it would be helpful to have a bucket stage which is given an upper and lower boundary, and the buckets are generated automatically at fixed, predefined intervals, for example

{{{}}
  $bucketInterval: {
    groupBy: '$timestamp',
    }}{{lower: ISODate("2014-10-23T00:00:00.000+02:00"),
    }}{{upper: ISODate("2014-10-24T00:00:00.000+02:00"),
    }}{{interval: 5*60*1000,
    }}{{output: {
      total:    {$sum: 1},
      incoming: {$sum: "$i"},
      outgoing: {$sum: "$o"},
    }}{
{{  }}}
}