1 /* 2 * Author: Jon Trulson <jtrulson@ics.com> 3 * Copyright (c) 2015 Intel Corporation. 4 * 5 * Permission is hereby granted, free of charge, to any person obtaining 6 * a copy of this software and associated documentation files (the 7 * "Software"), to deal in the Software without restriction, including 8 * without limitation the rights to use, copy, modify, merge, publish, 9 * distribute, sublicense, and/or sell copies of the Software, and to 10 * permit persons to whom the Software is furnished to do so, subject to 11 * the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be 14 * included in all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 17 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 18 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 19 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE 20 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION 21 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION 22 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 23 */ 24 #pragma once 25 26 #include <string> 27 #include <iostream> 28 29 #include <stdint.h> 30 #include <stdlib.h> 31 #include <unistd.h> 32 #include <string.h> 33 #include <fcntl.h> 34 #include <errno.h> 35 #include <termios.h> 36 #include <sys/time.h> 37 #include <sys/select.h> 38 #include <sys/types.h> 39 #include <sys/stat.h> 40 41 #include <mraa/uart.h> 42 43 const int MHZ16_DEFAULT_UART = 0; 44 45 // protocol start and end codes 46 const uint8_t MHZ16_START = 0x7e; 47 const uint8_t MHZ16_END = 0x7e; 48 49 namespace upm { 50 /** 51 * @brief MHZ16 Serial CO2 Sensor library 52 * @defgroup mhz16 libupm-mhz16 53 * @ingroup seeed uart gaseous 54 */ 55 56 /** 57 * @library mhz16 58 * @sensor mhz16 59 * @comname Grove CO2 Sensor 60 * @altname MHZ16 Serial CO2 Sensor 61 * @type gaseous 62 * @man seeed 63 * @con uart 64 * 65 * @brief API support for the Grove CO2 sensor 66 * 67 * This class implements support for the Grove CO2 sensor. 68 * 69 * Its CO2 detection range is 0-2,000 ppm. It requires a 70 * 2-3 minute warm-up time before reporting valid data. 71 * 72 * @image html mhz16.jpg 73 * @snippet mhz16.cxx Interesting 74 */ 75 class MHZ16 { 76 public: 77 78 79 /** 80 * MHZ16 constructor 81 * 82 * @param uart Default UART to use (0 or 1) 83 */ 84 MHZ16(int uart); 85 86 /** 87 * MHZ16 destructor 88 */ 89 ~MHZ16(); 90 91 /** 92 * Checks to see if there is data available for reading 93 * 94 * @param millis Number of milliseconds to wait; 0 means no waiting. 95 * @return True if there is data available for reading 96 */ 97 bool dataAvailable(unsigned int millis); 98 99 /** 100 * Reads any available data in a user-supplied buffer. Note: the 101 * call blocks until data is available to be read. Use 102 * dataAvailable() to determine whether there is data available 103 * beforehand, to avoid blocking. 104 * 105 * @param buffer Buffer to hold the data read 106 * @param len Length of the buffer 107 * @return Number of bytes read 108 */ 109 int readData(char *buffer, int len); 110 111 /** 112 * Writes the data in the buffer to the device 113 * 114 * @param buffer Buffer to hold the data read 115 * @param len Length of the buffer 116 * @return Number of bytes written 117 */ 118 int writeData(char *buffer, int len); 119 120 /** 121 * Sets up proper tty I/O modes and the baud rate. The default 122 * baud rate is 9,600 (B9600). 123 * 124 * @param baud Desired baud rate. 125 * @return True if successful 126 */ 127 bool setupTty(speed_t baud=B9600); 128 129 /** 130 * Verifies the packet header and indicates its validity 131 * 132 * @param pkt Packet to check 133 * @return True if the checksum is valid, false otherwise 134 */ 135 bool verifyPacket(uint8_t *pkt, int len); 136 137 /** 138 * Queries the sensor and returns gas (CO2) concentration and 139 * temperature data. 140 * 141 * @param gas Returned gas concentration 142 * @param temp Returned temperature in Celsius 143 * @return True if successful 144 */ 145 bool getData(int *gas, int *temp); 146 147 /** 148 * Sets the zero point of the sensor 149 * 150 */ 151 void calibrateZeroPoint(); 152 153 protected: ttyFd()154 int ttyFd() { return m_ttyFd; }; 155 156 private: 157 mraa_uart_context m_uart; 158 int m_ttyFd; 159 }; 160 } 161 162 163