MLX90620 with an Arduino Duemilanove Board

[ElectJC]

Hey guys,

Has anyone tried to implement the Melexis 90620 Temperature array sensor with lab view yet? Using Arduino?

[Klemen]

Hello,

I am using Arduino to communicate with MLX 90620 sensor, but not directly in LV. I am sending the IR data array to the serial port and read it in labview. I am using Arduino programming environment with i2c master library (http://homepage.hispeed.ch/peterfleury/avr-software.html).

It is possible to do this in LV (LIFA toolkit), but the problem I had was using the default Wire library, since it doesn't (didn't) support repeated starts which is needed for successful comunication (see MLX 90620 and eeprom datasheet write/read commands). I have seen that Arduino 1.0.1 now offers support for repeated starts (newest is Arduino 1.0.2, i think).

Best regards,

K

[Goob]

Klemen, How do you do that?  I am new to the arduino/labview, and I need to connect an MLX sensor to labview, but I am having trouble.  You said that you are able to send the data array to a serial port and read it in labview, and that is exaclty what I need to do, but need help on doing it.  Thanks!

[Klemen]

Dear Goob,

really sorry for the late replay, but with holidays and all...

Firstly, I would like to point out at the beginning that Melexis support is deeply dissapointing. They either don't know anything or don't reply.

Ok back to the problem:

1. Study the MLX datasheet (don't be supprissed about the inconsistency in the datasheet). All calibration results are stored on the EEPROM of the device.

2. Get the i2c master library (http://homepage.hispeed.ch/peterfleury/avr-software.html). This is a very clean, easy to understand library.

3. Check out the first post (it has helped me a lot):

http://arduino.cc/forum/index.php?PHPSESSID=6b434ed661fddce835a4260a819add5d&/topic,126244.msg949212...

The code is not very clean and there are some minor errors, but it is a great start. I also recommend reading the constants from EEPROM only once, since they are as the name suggests - constant!

Also put a capacitor between VDD and VCC on the sensor (I think I used 100nF).

4. You need to make sure the supply voltage of the sensor is as specified in the datasheet (2.6 V optimal). I've built a regulator from 5V to 2.6V (its simple, just google it).

5. Make sure that you connect all 4 pins of the sensor correctly (VDD, VSS, SDA - data, SCL - clock)

6. When programing, follow the example calculations in the datasheet. If you have the sensor connected to a PC (or laptop) I suggest sending data bytes from arduino to serial port and reading these in LV and then calculatig the temperatures.You could perform all the calculations on Arduino, but it is slower.

7. I suggest sending a character befor and after the data you send through serial communication, so as to know  the beggining and the end of the data transfer.

8. Use google for intermediate steps and modify them accordingly to your project.

Hope this helps you somewhat.

Best regards,

K