Arduino Focus control and Cloud sensor

[Euan]

I've ended up using the code from here it works really well, just change the loop time to 3000 instead of a bonkers 100

Lab3 - Laboratory for Experimental Computer Science

It gives it out like this:

Melexis MLX90614 temperature Sensor

object temp: 018.91 ambient temp: 018.23

object temp: 018.81 ambient temp: 018.23

object temp: 018.95 ambient temp: 018.19

Hand in front....

object temp: 024.87 ambient temp: 018.25

object temp: 025.5 ambient temp: 018.25

object temp: 025.7 ambient temp: 018.33

object temp: 025.13 ambient temp: 018.29

[Euan]

I can pull that out via Serial in Homeseer and do whatever with it, just need to switch from USB over to Serial and I can stick it out in the new housing I've made

[ncjunk]

I just started setting up to play and broke all the wires on the lead (using an old printer cable to connect to the MLX so not very sturdy...away from home so don't have a screw driver..DOH!

I am using code which is a focuser and cloud detector rather than just the code from the link. I then have VB recording the data every 10s, 1min, 5 min or 10 min depending on setting.

Next thing is to make a graph on the VB...also getting a new weather station that I hope to add in. I want to link this all to the website :/p

[yesyes]

the ambient temperature is the temperature of the chip.

your values are looking good i think. I've done integer only (for now) as I think you won't get sub-degree accuracy, really. Especially when it's aimed at the sky.

[yesyes]

OK, I spend some time on this. I got SNMP half working. It replies to one request and then crashes the Arduino.. :-/

Have to look into how to debug this...

There isn't a way to step through the code, is there?

[yesyes]

YES!! I fixed it...

How odd... replying to SNMP requests breaks the String objects. Worked around it by not using Strings....

Now I only need to add a few more OIDs...

[yesyes]

Done...

I can now read the light level from the LDR and the 2 temperatures from the sensor via SNMP!

I had no idea this could be done in a few hours. I thought it would take me weeks, considering this is my first Arduino project ever...

[yesyes]

If anyone is interested, here is the sketch.

It assumes an Arduino Duemillanove (will probably just run on others), an LDR on analogue pin 1, the MLX90614 sensor connected to I2C, the original Arduino Wiznet W5100 Ethernet shield and the 4bit LCD shield.

I'll put some of the code into functions next.

Weather_Station.zip

[yesyes]

Oh and here is the circuit that I used to connect the LDR (10k ohm nominal) and the MLX90614BAA to the Arduino. There is also the circuit for the experimental rain sensor.

[yesyes]

And a few pictures of the sensor box I built. It houses the LDR, the MLX90614BAA and the circuit above.

[George]

Thats looking very good, I'll post a piccy of mine when I can find the camera

BTW which LDR did you use and where did you get it from, Neil & I were discussing adding a LDR a couple of weeks ago.

[yesyes]

The LDR is this one here:

2 * LDR Light Dependant Resistor Sensor 10k nominal 10L on eBay (end time 29-Nov-10 10:59:55 GMT)

It's just a standard 10k LDR.

And the project box is this one here:

ABS Project Box & Aluminium Lid & Matrix Board (5 pack) on eBay (end time 12-Nov-10 10:04:06 GMT)

I think this is an excellent offer. 5 boxes with PCB for just over £5 delivered. Couldn't resist. ;-)

I glued the sensors into the box and hope that this will be water proof.

[yesyes]

Not very busy at work today, so I'm researching humidity sensors.

The SHT15 looks promising. It has humidity and temperature, allows for dew point calculation and has a I2C / SPI interface. The downsides are that it's tiny (but can be bought on a breakout board) and that it's rather pricey.

SparkFun - Humidity and Temperature Sensor - SHT15 Brea on eBay (end time 15-Dec-10 09:37:15 GMT)

There are other, far cheaper ones but they would be harder to interface with the Arduino...

[yesyes]

Don't know if I mentioned that before. The LDR is meant to help the cloud sensor. I think it was Neil who said that comparing ambient and object (sky) temperature to detect clouds only works reliably when it's dark. So the LDR will prevent cloud alarms during the day.

[ncjunk]

I believe the problem with day time temp may be the sun heating up the mlx case and giving higher ambient readings....but we can play.

Still very busy at work so getting a bit jealous of all this progress your making! Going to uk for the weekend so will pop by maplins in southampton and pick up an LDR and a few other things.

Oohh and i am writing some code to post an html file to a website for automatic posting of data.

[yesyes]

Ah, so you could either keep the sensor in the shade, though the IR part would still need to "look" at the sky. Or, alternatively, just put a LM35 onto an analogue pin and get a ambient temperature reading from the shade somewhere...

[ncjunk]

I think the better option is another temp sensor as putting the ir sensor in the shade implies a wall or object sheltering it...another posible source of ir radiation.

I have a similar weather station to one George has so will be using that. I would love to eaves drop on the wireless comms for that and steal the data but may have to do with the old usb cable to the base station instead.

[George]

I'm gradually losing the will to live

Ic2mster is causing me no end of grief, no matter which directory I place it in the sketch errors out when trying to compile, I have read and re-read this thread and the one's on the Arduino forum. I have reinstalled the Arduino software twice and still no joy.

Arrrrrrrrrrrrrrrrhhhhhhhhhhhhhhhhhhhhhhhh

[yesyes]

What's the error you're getting?

What version of the IDE are you using?

[George]

Latest version 0021, here's the error code:

sketch_nov19a.cpp:1:23: error: i2cmaster.h: No such file or directory

sketch_nov19a.cpp: In function 'void setup()':

sketch_nov19a:6: error: 'i2c_init' was not declared in this scope

sketch_nov19a.cpp: In function 'void loop()':

sketch_nov19a:16: error: 'I2C_WRITE' was not declared in this scope

sketch_nov19a:16: error: 'i2c_start_wait' was not declared in this scope

sketch_nov19a:17: error: 'i2c_write' was not declared in this scope

sketch_nov19a:20: error: 'I2C_READ' was not declared in this scope

sketch_nov19a:20: error: 'i2c_rep_start' was not declared in this scope

sketch_nov19a:21: error: 'i2c_readAck' was not declared in this scope

sketch_nov19a:23: error: 'i2c_readNak' was not declared in this scope

sketch_nov19a:24: error: 'i2c_stop' was not declared in this scope

[George]

Ive done some digging in this Arduino Forum - Melexis SMBus IR Thermometer - NFI

Reply #25

2) Download Peter Fleury's nice library...

BUT place it under /{arduino root}/libraries/"what-ever-folder" where the current Arduino software looks for the libraries when started. You also have to rename the "twimaster.c" to "twimaster.cpp" as instructed so that Arduino can build it when launched. You also have to create a "keywords.txt" file inside the "what-ever-folder" where you define the library functions (function names and KEYWORD2 only). Without doing this Arduino cannot find and build the library. You can copy and edit the keyword file from some other library or see some help at Arduino's LibraryTutorial (Sorry, but it seems I cannot mail any links - just google for it

Seems like this keywords txt is the cause of my problems, looked in all the other libraries and everyone has a keyword txt except the ic2master library

[yesyes]

did you import the library from the menu or did you just type #include <i2cmaster.h> ?

[yesyes]

Oh, and I don't have a keywords.txt in that folder either and it works for me.

[George]

did you import the library from the menu or did you just type #include <i2cmaster.h> ?

I tried both

Are you using the analog pins?

[yesyes]

yes, I'm using analogue pins 4 and 5. But that wouldn't explain the compile errors.

Have you named the folder "i2cmaster" ?