Diff: main.cpp

Revision:

0:99fdd85b4929

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+++ b/main.cpp	Sat Jun 14 02:25:52 2014 +0000
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+#include "mbed.h"
+#include "NOKIA_5110.h"
+
+/*
+Sketch to use with a Nucleo F401RE and a
+Sharp Optical Dust Sensor GP2Y1010AU0F to measure dust with a
+Nokia 5110 display to show result. Will also show results via USB on PC terminal program
+
+NOTE THAT THIS SENSOR USES 5V AND THE NUCLEO 3.3V. USE AT YOUR OWN RISK.
+I SHALL NOT BE HELD RESPONSIBLE FOR ANY DAMAGE TO YOUR HARDWARE.
+
+For non-Nucleo mbed platforms you need to change the pins. 
+
+!!!IMPORTANT!!!
+A brief note on the sensor and board voltage   !!!IMPORTANT!!!
+STM specify in their datasheet (Feb 2014, DocID025644 Rev 2, page 38) that
+pin PA1 is "FT" meaning 5V tolerant. Moreover, I have measured voltages of
+no more than 3.71V in my experiments. So you should make your own decision
+whether and how you want to connect the sensor. Use at your own risk.
+I shall not be liable for any damage. 
+
+This sketch is based on code by the following authors: Cyrille Médard de Chardon (serialC), Christophe Trefois (Trefex)
+Their work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
+To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-sa/3.0/ or send a letter
+to Creative Commons, 444 Castro Street, Suite 900, Mountain View, California, 94041, USA.
+Changelog:
+2014-Jun-08: Adapted to Nucleo
+2014-Jun-13: Added Nokia 5110 display
+
+Original documentation
+http://arduinodev.woofex.net/2012/12/01/standalone-sharp-dust-sensor/
+http://www.howmuchsnow.com/arduino/airquality/
+
+The code for the Nokia 5110 is adapted from work by Chris Yan as Revised: January, 2014
+
+For the scientifically inclined who are pressed for time there is a nice writeup about dust here:
+http://www.who.int/occupational_health/publications/en/oehairbornedust3.pdf
+
+Pin connections
+Sharp dust sensor GP2Y1010AU0F
+Data sheet: https://www.sparkfun.com/datasheets/Sensors/gp2y1010au_e.pdf
+App note:   http://sharp-world.com/products/device/lineup/data/pdf/datasheet/gp2y1010au_appl_e.pdf
+Remember to include the resistor and capacitor (polarity!) as described in the Sharp datasheet
+    Pin 1: Resistor - 5V (see datasheet)
+    Pin 2: Gnd (capacitor between 1 and 2 - see datasheet)
+    Pin 3: Digital D8
+    Pin 4: Gnd
+    Pin 5: +5V
+    Pin 6: Analog A0
+    Pins are counted left to right when looking at the connector from the front (i.e. so that you can see the pins)
+
+5110 Display
+    myPins.sce  = PB_6;
+    myPins.rst  = D2;
+    myPins.dc   = D3;
+    myPins.mosi = PA_7;//SPI_MOSI;
+    myPins.miso = NC;
+    myPins.sclk = PA_5;//SPI_SCK;
+I am not using the backlight. Feel free use another digital pin to power it
+*/
+
+Serial pc(SERIAL_TX, SERIAL_RX); //output for debugging
+ 
+DigitalOut myled(LED1);
+DigitalOut ledPower(D8);
+AnalogIn analog_value(A0);
+
+
+int samplingTime = 280;//280 microseconds
+int deltaTime = 40;//40 us to give total pulse width of 0.32ms
+int sleepTime = 9680;//LED off for 9680 us to take 1 measurement per second
+
+float dustDensityCN = 0,dustDensitySharp = 0, voMeasured=0, voCalc=0;
+ 
+int main() {
+  pc.printf("Starting sensor. It can take a few measurements until it becomes stable.\n");
+    LcdPins myPins;
+    myPins.sce  = PB_6;
+    myPins.rst  = D2;
+    myPins.dc   = D3;
+    myPins.mosi = PA_7;//SPI_MOSI;
+    myPins.miso = NC;
+    myPins.sclk = PA_5;//SPI_SCK;
+    pc.printf("LCD pins set ok\n");
+    NokiaLcd myLcd( myPins );
+    
+    // Start the LCD
+    myLcd.InitLcd();
+    myLcd.SetXY(char(0),char(0));
+    myLcd.DrawString("SHARP DUST SENSOR"); 
+
+    pc.printf("LCD started\n");
+
+  while(1) { 
+      myled = !myled;
+      ledPower=0; // power on the LED. Pull-down to activate
+      wait_us(samplingTime);
+      voMeasured = analog_value.read(); // Converts and read the analog input value  
+      wait_us(deltaTime);
+      ledPower=1; // turn the LED off. Pull up to turn off
+      wait_us(sleepTime);
+
+      voCalc = voMeasured*3.3;//Map 0:1 measured range to 0:3.3V
+  
+  // Original equation taken from Sharp data sheet measured in mg/m3
+  // Sharp don't give you a best fit line, so you have to guess
+     dustDensitySharp = 0.5/2.8 * (float(voCalc) - 0.7);
+
+  // Eqaution calibrated by Chris Nafis (c) 2012
+  // see http://www.howmuchsnow.com/arduino/airquality/
+  // measured in parts per 0.01 cf
+  // [I did not get meaningful values on my sensor with Chris' formula
+  // For me the Sharp graph works just fine. So make your own tests]
+     dustDensityCN = (float(voCalc) - 0.0356)*1.2;
+  
+      pc.printf(" - Measurment value: %1.3f", voMeasured);
+      pc.printf(" - Voltage calculated: %1.3f", voCalc);
+      pc.printf(" - Sharp's Dust Density [mg/m3]: %f", dustDensitySharp);
+      pc.printf(" - C. Nafis' Dust Density [pp.01cf](x10^4): %f\n", dustDensityCN,"\n");
+      
+        myLcd.SetXY(char(1),char(1));
+        myLcd.DrawString("Raw value:"); 
+        char measurestring[(((sizeof voMeasured) * 8) + 2)/3 + 2];
+        sprintf(measurestring, "%1.2f", voMeasured);
+        myLcd.DrawString(measurestring);
+
+        myLcd.SetXY(char(1),char(2));
+        myLcd.DrawString("Voltage:  "); 
+        char voltagestring[(((sizeof voCalc) * 8) + 2)/3 + 2];
+        sprintf(voltagestring, "%1.3f", voCalc);
+        myLcd.DrawString(voltagestring);
+
+        myLcd.SetXY(char(1),char(3));
+        myLcd.DrawString("Sharp dd: "); //Units: refer to printf above
+        char sharpstring[(((sizeof dustDensitySharp) * 8) + 2)/3 + 2];
+        sprintf(sharpstring, "%1.2f", dustDensitySharp);
+        myLcd.DrawString(sharpstring);
+
+        myLcd.SetXY(char(1),char(4));
+        myLcd.DrawString("Nafis dd: "); //Units: refer to printf above
+        char nafisstring[(((sizeof dustDensityCN) * 8) + 2)/3 + 2];
+        sprintf(nafisstring, "%1.2f", dustDensityCN);
+        myLcd.DrawString(nafisstring);
+ 
+  wait(1);
+}
+}
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