| 摘要 |
A sun dial including a housing, a light detector mounted on the housing exposed to detect ambient light, a logic circuit mounted in the housing for processing the detected light for determining over a preselected period of time the average light detected by the light detector, and an indicator to indicate upon demand, the average light detected during the preselected period of time. A method for determining average light detected over a period of time by detecting light above a preselected threshold indicative of darkness, while noting the time of darkness, adjusting the period of time by subtracting the time of darkness from the period of time, calculating the average light detected over the adjusted period of time, and giving a visual indication of the average light detected.
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