SHARP Gesture sensor GP2AP054A00F EVB Question

[Finalc]

Q:

目前開發版一上電後，螢幕上會顯示Lx 跟 r

Lx是環境亮度，那r 指的是甚麼呢?

有發現r 會依轉動板子的角度在0.1M跟0.1L間跳換

After the current development version is powered on, the screen will display Lx and r.

Lx is the ambient brightness, what does r mean?

It is found that r will jump between 0.1M and 0.1L depending on the angle of rotating the board.

 

A:
“r”表示IR和Clear PD數據的比率。如果比率大，則傳感器測量的光源具有大量IR光。“L”，“M”，“H”的最後一個字符表示寄存器的內部範圍設置。自動增益控制功能安裝在MCU軟件中。

關於ALS功能，Lux數據由兩個PD輸出計算。
（CLR = CLEAR）
例:
Lux =α✕CLEAR – β✕IR
比率= IR / CLEAR

α，β由比率優化。
根據面板，這些係數也是必要的。

該傳感器根據兩個波長Clear＆IR計算照度（Lux）。
r0.1：“r”表示Clear＆IR的比率，
r = IR / Clear
L，M，H：表示Lux的測量模式。
 (Low Lux Mode / Middle Lux Mode / High Lux Mode)

關於波長，您可以從附頁-23中的圖片更容易地對其進行了解。
它顯示了GP2AP054A00F的波長響應度。
此外，LED燈或熒光燈或白熾燈的波長成分也不同。
因此，我們的傳感器在計算照度時計算比率。
在你的照片中，r = 0.1和M.
這意味著低IR條件。也許光源是LED或熒光燈。
“M”表示“中間勒克斯模式”。
這種“Lux mode”差異不會影響實際“Lux ”值的顯示。
所以你不需要關心它。

“r” means the ratio of IR and Clear PD data.
If the ratio is large, the light source which a sensor is measuring has a lot of IR light.
The last character of “L”,”M”,”H” show the internal range setting of register.Auto gain control function is installed in MCU software.
We don’t have Arduino software, so please refer to the PIC MCU sample code.

ex:

About ALS function, Lux data is calculated by two PD outputs.
(CLR = CLEAR)

ex:
Lux = α✕CLEAR – β✕IR
ratio = IR/CLEAR

α、β is optimized by the ratio.
These coefficients are also necessary to change according to the panel.This sensor calculates illuminance(Lux) based on two wavelength, Clear & IR.
r0.1 : “r” means ratio of Clear & IR, r=IR/Clear

L, M, H : it means measurement mode of Lux. (Low Lux Mode / Middle Lux Mode / High Lux Mode)

Regarding the wavelength, you may more easily image it from the picture in the attached page-23.

It shows the wavelength responsivity of GP2AP054A00F.

And also the wavelength components is different at LED lamp or Fluorescent lamp or Incandescent lamp.

Therefore, our sensor is calculating the ratio when calculating illuminance.

At your picture, r=0.1 & M.

It means low IR condition. Maybe the light source was LED or Fluorescent lamp.

And “M” means “Middle Lux Mode”.

Such “Lux mode” difference would not affect the showing of actual “Lux” value.

So you don’t need to care of it.

 

 

Document : GP2AP054A00F__ApplicationNote_20161228

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