diff options
Diffstat (limited to 'peripheral/libupm/src/mg811/mg811.cxx')
-rw-r--r-- | peripheral/libupm/src/mg811/mg811.cxx | 94 |
1 files changed, 0 insertions, 94 deletions
diff --git a/peripheral/libupm/src/mg811/mg811.cxx b/peripheral/libupm/src/mg811/mg811.cxx deleted file mode 100644 index 622dd85..0000000 --- a/peripheral/libupm/src/mg811/mg811.cxx +++ /dev/null @@ -1,94 +0,0 @@ -/* - * Author: Jon Trulson <jtrulson@ics.com> - * Copyright (c) 2015 Intel Corporation. - * - * Thanks to public domain code by Martin Liddament for some useful clues! - * http://www.veetech.org.uk/CO2_Monitor_Sketch_2_Operation.txt - * and sandbox electronics (http://sandboxelectronics.com/?p=147). - * - * Permission is hereby granted, free of charge, to any person obtaining - * a copy of this software and associated documentation files (the - * "Software"), to deal in the Software without restriction, including - * without limitation the rights to use, copy, modify, merge, publish, - * distribute, sublicense, and/or sell copies of the Software, and to - * permit persons to whom the Software is furnished to do so, subject to - * the following conditions: - * - * The above copyright notice and this permission notice shall be - * included in all copies or substantial portions of the Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, - * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF - * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND - * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE - * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION - * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION - * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. - */ - -#include <iostream> -#include <math.h> -#include "mg811.h" - -using namespace std; -using namespace upm; - -// voltage gain of the DC amplifier -static const float dcGain = 8.5; - -MG811::MG811(int pin, int dpin, float aref) : - m_aio(pin), m_gpio(dpin) -{ - m_aRes = m_aio.getBit(); - m_aref = aref; - - m_gpio.dir(mraa::DIR_IN); - - // these are just placeholder values (coarsely measured during - // development), you should determine the appropriate values (in - // volts) for your environment at the specified concentrations. Use - // the getReferenceVoltage() method to get these values at 400ppm - // and 1000ppm respectively. Good luck. - setCalibration(0.5514, 0.370); -} - -MG811::~MG811() -{ -} - -float MG811::volts() -{ - int val = m_aio.read(); - - return(float(val) * (m_aref / float(1 << m_aRes))); -} - -void MG811::setCalibration(float ppm400, float ppm1000) -{ - m_zeroPointValue = ppm400; - m_reactionValue = ppm1000; -} - -float MG811::getReferenceVoltage() -{ - return (volts() / dcGain); -} - -float MG811::ppm() -{ - static const float log400 = log10f(400); - static const float log1000 = log10f(1000); - - float val = volts(); - - if ((val / dcGain) >= m_zeroPointValue) - return 0.0; - else - return powf(10.0, ((val/dcGain)-m_zeroPointValue) / - (m_reactionValue / (log400-log1000))+log400); -} - -bool MG811::thresholdReached() -{ - return (m_gpio.read() ? true : false); -} |