Though the Lichttonorgel was not a commercial success, it was the very first sample player ever. It was invented and developed by Edwin Welte, a member of the famous company known for their orchestrions and reproducing pianos. The latter instruments can be seen in action in several museums in the south-west of germany.
BTW: The piano roll they invented still can be found as an editor in many software sequencers to create and manipulate control events.
The Lichttonorgel can be seen as one of the predecessors of the Optigan and Orchestron, a competitor of the Mellotron. New sound disks for the Optigan are still available via optigan.com, including sound samples.