STEM与日常科技·英语30篇（9）

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超市购物车如何在昏暗停车场自动照亮行进路径

Each cart has small motion-activated LED strips embedded along its front frame and wheel hubs.
When the cart moves faster than walking speed, the lights brighten and widen their beam angle.
A light sensor detects ambient brightness, so the system only activates after sunset or in covered garages.
The battery recharges through kinetic energy generated each time wheels rotate on pavement.
You’ll see a soft blue glow outlining the cart as you push it toward your car.
If you pause for more than ten seconds, the lights dim but stay ready to brighten again.
Parents often notice how much easier it is to spot their cart among dozens in the dark.
The light pattern changes subtly when turning, helping guide your path around obstacles.
No switches or apps are involved—everything responds naturally to movement and light levels.
This feature works reliably even during rainy or foggy evenings without extra maintenance.