Hitechnic Color Sensor 測試

一、硬體方面

color sensor 接在nxt主機上的IN_4。

二、軟體方面

根據［Third-party sensors: a review of some Hitechnic’s sensors］一文提到：
The new and totally redesigned HiTechnic Color Sensor Version 2 (V2) operates by using a single white LED (light emitting diode) to illuminate the target and analyses the color components of the light reflected by the target’s surface and calculates a Color Number that is returned to the NXT program.

Sensor Register Layout

Adress	Type	Contents
42H	byte	Color number
43H	byte	Red reading
44H	byte	Green reading
45H	byte	Blue reading

Procedures are already available in Bricxcc to use the sensor:

• SetSensorLowspeed() initializes the I2C communication with the sensor.
• SensorHTColorNum(port) returns the value of Color number.
• ReadSensorHTRawColor(port, rouge, vert, bleu) returns the RGB readings.
• ReadSensorHTColor(port, index, rouge, vert, bleu) returns the value of Color number, and the RGB readings. See the code example at the end of the article ...

所以在NXC的程式基本採用的指令，包含二個:
1.　SetSensorLowspeed(IN_4)
2.　ReadSensorHTColor(IN_4,colorvalue,r,g,b)
其中，IN_4是彩色感應器接向IN_4，而colorvalue是經由color sensor回應的讀值，r,g,b分別為red,green,blue三原色的數值。

三、程式碼

#define ColorSensorPort IN_4

task main()
{

 byte r,g,b;
 byte colorvalue;
 SetSensorLowspeed(ColorSensorPort);

 while(true)
 {
     ReadSensorHTColor(ColorSensorPort, colorvalue,r,g,b);
     NumOut(0,LCD_LINE3,colorvalue);
     if (colorvalue==0)  PlayTone(880,25);
     Wait(25);
     ClearScreen();
 }
}

上述程式是說:
當color sensor讀值(colorvalue)=0，則PlayTone一個短音。
colorvalue=0-->黑色