Litar: The LIDAR Air-Guitar
Hema Nookala posted on March 30, 2018 |
Play your own solo after checking out the Litar: the LiDAR Air Guitar.

The divide between the arts and sciences is nothing new; it’s a battle that has been waging since the dawn of humankind. However, in recent years there has been a distinct marriage between the two. More and more people are turning ideas into reality using the technology we’ve become accustomed to along with the creativity with which we were born. Every realm—music, art and theater—is being augmented with smart technology.

What used to be humans dreaming of the impossible has become humans creating the impossible. Many people have memories, as children or even adults, of rocking out to a guitar solo on an air guitar in front of tiny television screens. The air guitar is a phenomenon that seems to surpass age, and now it has surpassed imagination.

One intrepid inventor has created the Litar, a functional air guitar. It features four light detection and ranging (LIDAR) air strings that use a remote sensing method of pulsing lasers to measure variable distances. While LIDAR has been used to generate 3D information about Earth’s surface, this particular project proves that even technology created for data collection may have limitless ways people can alter it to suit them.

The current Litar, after a few iterations.
The current Litar, after a few iterations.

To create the Litar, the first step was to make a bridge between human interaction and technology. This was done using MappyDot sensors—smart sensors used to measure distances up to 2 meters with a 25-degree field of view. For this air guitar, they were provided by a 2017 Hackaday Prize. The sensors can be used for area mapping, gesture recognition and motion sensing. With the Litar, they’re used to create the most important part of the guitar: the strings.

The air strings were initially created using three MappyDot sensors. Two were used to define two borders for the strings and the last one obtains the distance of the finger on the string. For practicality there is a larger gap between the larger-than-average air guitar strings. Low latency input, or low-lag processing of information, along with Bluetooth capabilities, allows for physical strumming or precise control through a phone or laptop.

A representation of how the sensors overlap to create the air guitar strings.
A representation of how the sensors overlap to create the air guitar strings.

The inventor wanted more than just to slash a hand through the air for a symphony of sound but also to have chord control and vibrato effects. This was first attempted by using 2D Hall effect joysticks. When the design was tested, it was soon realized that moving fingers laterally for the joysticks while holding the Litar caused undue strain. Using this feedback, the inventor simplified the joysticks to linear Hall effect sensors, which can be easily wiggled for a vibrato feel. 

Comparison between joystick sensors and linear sensors.
Comparison between joystick sensors and linear sensors.

The sensors and linear buttons together create a simple yet stylistic version of the air guitar. Using MappyDot+, a more advanced sensor, the guitar can be refined with increased light sensing capabilities in differently lit settings, an adjustable field of view and ability to alter string size via software. These additions also increase user-friendliness.

The blend of music and technology seems to have no end, and others are forging new paths with inventions such as laser guitars or LED light strips that change color based on sound. One such creation that blends sensor applications with the creative side is the BioMuse. It is a bioelectric signal controller that allows the user to send signals to an interface that translates muscle or eye movement or brainwaves into music. Check out this video for a demonstration.

Atau Tanaka - new Biomuse demo from STEIM Amsterdam on Vimeo.

While creativity may have no bounds, sometimes it’s tough to know where to start. The new engineering.com ProjectBoards provide a forum to brainstorm ideas, request help, get project feedback or share a project.. Pursue your passions without fear and start a project today. 

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