Parents of newborns sometimes devise ingenious MacGyver-esque devices to keep their babies entertained, or to, more importantly, soothe them to sleep. One inventive techie, who goes by the YouTube handle macjonesnz, has created a ridiculously inexpensive self-rocking chair using only his computer and a piece of string.

The creative parent, using Ubuntu Linux, wrote a program commanding his CD-ROM tray to repeatedly eject and then pull back in. Connecting the tray to his baby’s car seat with a piece of string, macjonesnz effectively created a continuous baby-rocker. As the video clearly demonstrates, Baby Charlotte v1.0 is resting peacefully — and for a fraction of the price of some other non-traditional baby toys.

Checkout the video here