K33 sensor interface using I2C with matlab

HI all, I have interfaced K30 sensor using I2C with matlab below is the code: a=arduino('com1', 'nano3', 'Libraries', 'I2C'); scanI2CBus(a); dev = i2cdev(a,'0x68'); mod_read=[34,0,8,42];%hex values converted to decimal write(dev, mod_read); pause(20e-3); out = read(dev, 4,'uint8'); ppm=int16(out(2))*256+int16(out(3));

When i try the same code with K33 sensor i am getting “Failed to read 4 uint8 value(s) from the device.”

when i went through the some documents i found sensor will be sleep mode so to wake it up we need to send pulse on SDA line hence i modified the code as shown below:

a=arduino('com1', 'nano3', 'Libraries', 'I2C'); scanI2CBus(a); dev = i2cdev(a,'0x68'); mod_read=[1,0]; write(dev, mod_read); mod_read=[34,0,8,42];%hex values converted to decimal write(dev, mod_read); pause(20e-3); out = read(dev, 6,'uint8')

output which I am getting is: out =

33 0 0 33

2nd and 3rd I am getting zero that means K33 sensor is not responding, I think it is because sensor does not start to measure CO2 and also I am not getting why first byte is 33.

also in below link: http://co2meters.com/Documentation/Datasheets/DS-K33ELGBLG-PRODUCTDESCRIPTION.pdf

i see on page 2

There are three ways to activate measurement/logging, here I few questions: 1. Do I need to short AnIn1, means do I need to short both the pins as mentioned on page 2 of PDF

  1. Same goes for Zero calibration and Background calibration, to get the same done do I need to short the pins as mentioned on page 2 of PDF

  2. What is Command “Force start measurement” and Command “Single measurement”?

kindly help me on the same, it would be great help.

Thanks Mahadev

sensor i am using :http://www.co2meter.com/products/k33-environmental-logger-co2-sensor