Gobetwino

Nico - many thanks for that; I've been meaning to play with Gobetwino for a while now and you gave me the impetus I needed! Now I need to make it do what I want it to do !!

You're very welcome, Neil! What is it you are wanting it to do?

Hi Neil,

That's great! Good idea about using Notepad - much quicker to start and less stuff that can go wrong. I had something like a 10 second delay just to make sure. I think you can also do a serial.read() which (I think) waits to get the result from the program startup.

I was thinking of maybe looking into the gobetwino logging feature as well, which makes the timestamps easier. So in the command you'd have to choose the one for logfile.

And I suppose for either case you could have it type the data into a .csv file (it kinda looks like that's what you are doing already?), and then it can be imported as a spreadsheet for graphing or whatnot.

And yes, I totally see the scenario. Have you actually been running it like that already?

I've been busy all week trying to get all my other work done so I can get this installed in my greenhouse soon too. I'm still having a bit of trouble getting my LM34 Fahrenheit sensor to give believeable temperatures though.

My tomato plants are looking pretty happy too. It being end of March I think the chance of a hard frost getting into the greenhouse is pretty slim now. Forecast says we still dip down to 0 C every night though...

Looking forward to seeing your blog too!

Cheers,

-Nico

Hi Nico,

I think the initial serial read gets the program PID after startup. However, the bigger issue is waiting for the file to open on the networked PC.....watching the screen, Notepad seems to open fairly qickly on the W7 device, but with an untitled (ie new) file. Some time later - several seconds, the filename displayed changes to be the one specified in the gobetwino command line parameter. I had to put in another delay to make sure I didn't start sending data too soon.

The gobetwino logging feature does look interesting, because of the timestamps - I may get to try that as well, locally first and then over the network.

Sadly, my setup is only running with the netbook and desktop side by side on my desk - I keep thinking of reasons not to take the arduino and the netbook out into the greenhouse just yet.

My latest idea is rather than leave the desktop switched on overnight, get the netbook/arduino to log data to a local file and then when it has finished - after a specific number of samples -  to ping the desktop and wait until it is there and then copy the data file over the network to the desktop.

I have tested the gobetwino file copy (but not over the network yet). I haven't tried the gobetwino pingt.

I am using LM35 temp monitors - they are OK but they have problems of their own - I haven't sorted all of those out yet, but if I take enough readings (100) at say 20mS intervals and take an average, I get reasonable results.

I wish I had more time - including time to write a blog about all my adventures with the arduino greenhouse data logger. I'll get to it soon!

All the best

Neil

Hi Neil,

I see - that file open would add a fair chunk of time, especially over the network.

Would it be possible to just write the file on the netbook in a shared folder, and then use the other computer to connect to the netbook's share in the morning?

I think the LM35 might be just the Centigrade version of the Fahrenheit sensor I have (or vice versa), so in theory they likely get hooked up the same way. Did you have to add a resistor to it?

Tomorrow being, theoretically at least, a "day of rest" I should be entitled to some tinkering time, methinks!

Cheers,

-Nico

Hi Nico

Doh!  why didn't I think of that - I'm always looking for a "clever" solution that exploits as much as possible.......sighs.

I just have the LM35 connected across +5v and 0v, with the centre leg delivering 10mV/deg celsius, but, with an effective offset of 2 deg, because the o/p is 0v at 2 deg.

The first problem I encountered was that the first reading in any set of readings is always significantly lower than the rest. Apologies if you already know this!

On googling, I find the problem is alleged to be a combination of at least 2 issues:

1. The LM35 is relatively high impedance, compared with the analog pins on the Arduino, so there are current flow problems or something like that.

2. The Arduino analog pins are multiplexed & it takes time for that to stabilise when you switch pins - ie reading more than 1 analog pin.

Anyway, the recommended solution seems to be to read the pin, discard the reading, wait about 5 mSec and then read it again.............seems to be the answer.

My second problem is a result of me being lazy and not using a screened cable for the LM35 that needs to be a long way from the Arduino.......the signal is quite low - 200mV for 20 ish celsius.......so I get quite a bit of hum and variability on those readings............just haven't got round to replacing the cable!

I have been in the garden and greenhouse all morning and about to partake of Sunday lunch....best meal of the week.

Hope you get some time to tinker

Neil

Hi Neil,

Thanks for the hints on the temp sensor, I'll give that a shot.

I spent most of yesterday actually doing some planting in the greenhouse, but I took some time today to work on the MSP430 launchpad that I have here - it's that $4.30 (includes shipping!) board from TI. The basic demo it comes with sends temperature from it's onboard temperature sensor via serial to a windows GUI.

I figure that would be a good unit for this project, as it's so inexpensive. Then it doesn't matter as much if a slug shorts it out

So I've been modifying the demo code to remove the unwanted parts of the demo and to make it send a readable string for the temperature, rather than a single byte. Wow I have to tell you that's nasty cryptic stuff - it's C but not nearly as clear and easy as our friend the Arduino!

It doesn't have as much stuff (power, memory, pins) as the Arduino, but for many projects it could make a viable alternative. Too bad the programming environment is so complex.

I got it sending strings for the temperature, so it's just a step away from hooking up to gobetwino.

Then I got an email from a client needing some stuff, so I guess I best get on that!

Hope you're off to a good start this week.

Cheers,

-Nico

Hi Neil,

Thanks for the hints on the temp sensor, I'll give that a shot.

I spent most of yesterday actually doing some planting in the greenhouse, but I took some time today to work on the MSP430 launchpad that I have here - it's that $4.30 (includes shipping!) board from TI. The basic demo it comes with sends temperature from it's onboard temperature sensor via serial to a windows GUI.

I figure that would be a good unit for this project, as it's so inexpensive. Then it doesn't matter as much if a slug shorts it out

So I've been modifying the demo code to remove the unwanted parts of the demo and to make it send a readable string for the temperature, rather than a single byte. Wow I have to tell you that's nasty cryptic stuff - it's C but not nearly as clear and easy as our friend the Arduino!

It doesn't have as much stuff (power, memory, pins) as the Arduino, but for many projects it could make a viable alternative. Too bad the programming environment is so complex.

I got it sending strings for the temperature, so it's just a step away from hooking up to gobetwino.

Then I got an email from a client needing some stuff, so I guess I best get on that!

Hope you're off to a good start this week.

Cheers,

-Nico