The InterActivator is a holding rail located inside an elevator. Its goal is to enhance the elevator ride experience, whether a single person is taking the ride and whether two or more people are. By counting the number of people that are holding the rail at any given time, the InterActivator selects and plays appropriate music:

For one person – quiet songs are played, such as Akon’s “Lonely”.
For two people – more joyful songs are played, such as Bill Wither’s “Just The Two Of Us”.
For three people – happy and faster pop music is played, such as “1, 2, 3″.
For four people and more – dance and party music, such as Pinks’ “Get The Party Started”.

interactivator by dor leist and udi oren



The project brief focused on the interaction between two or more people which takes part in a shared situation. We chose the elevator ride situation because we were interested in exploring how can we reduce or even eliminate the awkwardness in an elevator when two people who don’t know each other take a ride together. With time, the project developed to provide the experience for up to four people.

When we tested the InterActivator in a real elevator (within our university), we found that people were happy to discover that they can control the played music. They started to talk with each other, and some did not want to get out when the elevator arrived to their floor! There were even some who forgot to press the elevator’s button.


The rail is built from two units made of a bent metal profile that are connected to an Arduino board from their bases. By measuring the capacity in each of the two parts of the rail, the program can determine how many people are holding the rail simultaneously (there is no influence if one holds in one or both hands). In total it can distinguish between one, two, three and four people.

The base of InterActivator houses an Arduino board, a speaker and a computer that contains the processing software and sound files. The software is a combination of Max and Arduino programs (using the “MaxDuino” component to communicate between the two). It reads the capacity value, calculates how many people holding the rail at any given time and then selects and plays the appropriate song from memory.


Udi Oren, Dor Leist