GroveColourSensor.hpp

00001 /*
00002  * Copyright (c) 2006-2013 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 #ifndef __GROVE_COLOUR_SENSOR_HPP__
00018 #define __GROVE_COLOUR_SENSOR_HPP__
00019 
00020 #include "mbed.h"
00021 
00022 /**
00023  * This module is based on the color sensor TCS3414CS with digital output over I2C.
00024  * http://www.seeedstudio.com/wiki/index.php?title=Twig_-_I2C_Color_Sensor_v0.9b
00025  *
00026  * example use:
00027  *
00028  *     GroveColourSensor colorSensor(I2C_SDA0, I2C_SCL0);
00029  *
00030  *     colorSensor.powerUp();
00031  *     unsigned colour;
00032  *     for (colour = GroveColourSensor::GREEN; colour < GroveColourSensor::NUM_COLORS; colour++) {
00033  *         uint16_t colourValue = colorSensor.readColour(colour);
00034  *         ...
00035  *     }
00036  *     colorSensor.powerDown();
00037  */
00038 
00039 class GroveColourSensor {
00040 public:
00041     enum Colour_t {
00042         GREEN = 0,
00043         RED,
00044         BLUE,
00045         CLEAR,
00046         NUM_COLORS
00047     };
00048 
00049     GroveColourSensor(PinName sda, PinName scl) : i2c(sda, scl) {
00050         /* empty*/
00051     }
00052 
00053     void powerUp(void) {
00054         static const char powerUpCommand[] = {0x80, 0x03};
00055         /* turn on the color sensor */
00056         if (i2c.write((SEVEN_BIT_ADDRESS << 1), powerUpCommand, sizeof(powerUpCommand)) != 0) {
00057             error("failed to power up the sensor");
00058         }
00059     }
00060 
00061     void powerDown(void) {
00062         static const char powerDownCommand[] = {0x80, 0x00};
00063         /* turn on the color sensor */
00064         if (i2c.write((SEVEN_BIT_ADDRESS << 1), powerDownCommand, sizeof(powerDownCommand)) != 0) {
00065             error("failed to power down the sensor");
00066         }
00067     }
00068 
00069     uint16_t readColour(Colour_t colour) {
00070         char readColorRegistersCommand = 0xb0 + (2 * static_cast<unsigned>(colour));
00071         i2c.write((SEVEN_BIT_ADDRESS << 1), &readColorRegistersCommand, 1 /* size */);
00072 
00073         uint16_t colourValue;
00074         i2c.read((SEVEN_BIT_ADDRESS << 1), reinterpret_cast<char *>(&colourValue), sizeof(uint16_t));
00075         return colourValue;
00076     }
00077 
00078     uint16_t readColour(unsigned colour) {
00079         if (colour >= NUM_COLORS) {
00080             return 0;
00081         }
00082 
00083         return readColour(static_cast<Colour_t>(colour));
00084     }
00085 
00086 private:
00087     static const uint8_t SEVEN_BIT_ADDRESS = 0x39;
00088 
00089     I2C i2c;
00090 };
00091 #endif /* #ifndef __GROVE_COLOUR_SENSOR_HPP__ */