| 摘要 |
<p>The icy surface indicator sign comprises a light source, such as a plurality of LEDs, that are arranged to illuminate when a detected temperature falls below a predetermined value. The sign may comprise a front plate 1 behind which is located a back shell 2 that houses a printed circuit board (PCB) 3 having a micro-controller, the LEDs and a temperature sensing chip. The PCB may be powered by batteries contained in a battery box 4 covered by a silicone/rubber battery cover plate 5. The LEDs may flash to indicate a frozen road surface when a temperature measured by the temperature sensing chip falls to 3 degrees centigrade. If the temperature subsequently rises above 3 degrees centigrade, the micro-controller may be arranged to ensure that the LEDs continue to flash until 48 hours has passed, thereby ensuring that the ice creating the frozen road surface has thawed.</p> |
