SAN FRANCISCO, May 7 (Reuters) - Luminar Technologies ( LAZR )

, a maker of lidar sensors for self-driving cars, said

on Tuesday that Tesla was the largest customer for its

sensors in the first quarter, accounting for more than 10% of

its total revenue of $21 million during the period.

Tesla's electric vehicles that are sold do not use lidars

and it is not clear where Tesla used the sensors. Tesla CEO Elon

Musk previously slammed rivals' use of the lidar sensors, which

he called "expensive appendices."

"Lidar is a fools' errand. And anyone relying on Lidar is

doomed," Musk said in 2019.

Lidar, which stands for light detection and ranging, shoots

out light pulses that are reflected off objects, allowing

self-driving systems and driver-assistance software to gain a

three-dimensional map of the road. Many self-driving companies

and experts regard it as a crucial component, especially during

low-light situations.

Tesla eliminated other sensors like radars and sound sensors

in recent years. It relies on cameras to detect objects for its

Autopilot or Full Self-Driving software, which does not make its

vehicles autonomous.

Photos of Tesla vehicles with lidar sensors on their roofs

were circulated on social media. Tesla in the past denied

speculation that it may use lidars as part of its Autopilot

system, saying, "We regularly test our own technologies against

other sensors to calibrate our camera, sonar and radar system."

Musk is betting big on self-driving cars, planning to unveil

a robotaxi in August. Rivals like GM's Cruise have scaled

back on investments in self-driving cars, hampered by heavy

investments and technological and regulatory challenges.

Luminar ( LAZR ) posted a loss of $10.46 million in the first

quarter. Its shares closed at $1.65 each on Tuesday, compared

with its peak of $41.80 in 2020.

The Florida-based company said last week it would cut its

workforce by about 20% and reduce in-house manufacturing as part

of restructuring plans.