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Author Topic: Arduino and MLX90620 16X4 pixel IR thermal array  (Read 32874 times)
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Hi guys!
In my case, it seems the program stops at i2c_start_wait()
Could you help me to solve this?

I am sure the connection is correct. I connect to arduino 3v3 and regulated to 2v6 by LM317 as suggested. I also connect 4k7 resistors to scl and sda.

Any help is really appreciated. Thanks.

=========================
void read_EEPROM_MLX90620()
{
  i2c_start_wait(MLX90620_EEPROM_WRITE);
//STOPS HERE...... :-(
=========================
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Hey All,

  I'm using the code from reply #23 (Mr.Sparkfun himself) to read data from the MLX90620.  It works, but I'm getting data that "jumps" around - i.e. there's sometimes a variation of 5 degrees between datasets when the sensor is pointed at nothing but the ceiling.  Anyone else experience this?  This is what I mean(I changed the output to Celcius - I'm Canadian!):
Code:
[size=10pt][size=10pt][size=10pt]
27.71 27.08 26.47 27.09 27.65 27.11 27.63 24.56 26.50 26.52 24.80 26.47 24.25 27.60 25.45 25.92
25.46 27.59 26.03 26.50 26.06 26.03 27.07 27.07 27.07 27.54 26.58 24.87 24.60 25.14 24.62 25.99
26.55 26.58 28.01 26.55 26.08 25.15 27.53 27.07 25.10 27.06 26.12 25.48 26.07 27.06 26.09 25.46
27.07 26.07 28.05 27.58 27.07 25.53 26.55 27.61 25.95 24.41 25.51 27.04 24.19 26.53 25.45 26.49

23.88 24.60 23.33 24.31 24.15 23.05 22.52 21.98 23.01 26.52 23.64 24.60 25.39 24.38 24.90 25.33
22.72 24.44 24.46 22.41 22.96 23.48 22.43 23.15 23.04 26.10 23.59 27.61 23.59 25.14 23.63 24.93
23.63 23.16 23.66 23.40 24.60 25.15 25.15 23.93 23.59 25.63 27.06 25.48 23.55 25.10 23.63 24.38
23.44 24.55 22.53 21.45 24.35 23.44 22.33 23.24 23.68 26.01 24.99 23.06 23.60 22.68 22.68 22.9 [/size][/size][/size]

I'm using a buck converter to output the 2.6volts from 3.3v supplied by the an Arduino with 4.7ohm resistors on  SDL and SDA.  In the commented intro to his code, he states that the wiring should be :
A5 to 330 ohm to SCL
 A4 to 330 ohm to SDA
 3.3V to VDD
 GND to VSS

but I've read that the readings won't be too accurate using 3.3v.  Anyone have any ideas on where I'm going wrong?   

Cheers,

Paul
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