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16  Community / Exhibition / Gallery / Re: Manchester encoding library for RF links. on: January 19, 2013, 03:21:58 am


Great work!

This is gold to me. I have been considering rolling my own Manchester encoding library and was quite puzzled that there wasn't one available already.

A little bit unfortunate that it seems to have split/forked into two (carl47 original and mchr3k streams).

Am I right to assume that the preferred version if the new mchr3k version on Github? (as you seem to suggest in you comment above regarding the bug carl47).

Thanks for putting together and sharing!

Anders

17  Community / Exhibition / Gallery / Re: 20 Arduino projects of 2012 on: January 09, 2013, 04:13:13 am

Nice collection!

Makes me wish for a "vote for" or "submit candidate" feature. I am sure there are lots of cool things being done that deserve more attention and that can act as inspiration to us all.


Anders
18  Community / Exhibition / Gallery / Re: Yet another Humidity and Temperature logger on: January 06, 2013, 02:13:10 pm
now you have humidity and temp you can calc the dewpoint.

Wow! Thanks! That might prove useful actually, both in terms of tracking mold conditions and in the balcony greenhouse I hope to build in a month or two.

19  Community / Exhibition / Gallery / Re: Yet another Humidity and Temperature logger on: January 06, 2013, 01:14:35 pm
:-)

Thanks!

Edge cases next and then the data logging shield.

Your support has been fantastic! Thanks again.

Anders

20  Community / Exhibition / Gallery / Re: Yet another Humidity and Temperature logger on: January 06, 2013, 11:31:15 am

Quote
Please post your new code,

I pushed the latest code to github: https://github.com/aweijnitz/Hygrometer
21  Community / Exhibition / Gallery / Re: Yet another Humidity and Temperature logger on: January 06, 2013, 11:21:57 am
Thanks for coming back on it!

I think the whole thing works and I made a silly mistake while reading the results. I also learned something new about our indoor climate perhaps.

First:
I think the apparatus works. My reference, the analog meter, showed the same value and has continued to do so. That means my circuit and the analog meter either both work or have the same kind of strange issue (not likely).

Second: (my reading mistake)
I said 12:34, because that is what I read on the graph and at 12:34 everything was static and quiet. HOWEVER I didn't think about the time zone when writing my script to convert the timestamps to JSON data. The timestamp is CET and 12:34 is in reality 13:34.
At 13:34 my wife came home after having run 15km in the Munich Winterlauf Series.

Needless to say the door to the stairwells was open for a while and she was wet and still perspired after having run in the wet weather.
We then closed the door and no windows where opened for a couple of hours. Two hours later (15:39 CET) we vented the flat again and the humidity dropped again.

I have time zone corrected the conversion tool and uploaded the latest data as illustration.
Same place: http://wohnung.se/arduino/hygrometer/data.html

Thanks again for all the help and friendly support!

Anders






22  Community / Exhibition / Gallery / Re: BlinkIT on: January 06, 2013, 08:39:53 am

Thanks!,
will have a look at the code.

Anders
23  Community / Exhibition / Gallery / Re: BlinkIT on: January 06, 2013, 08:22:02 am
Yes,
laser beam is on my mind too. It would be very cool to use as an unusual and alternative wireless transfer technology. I think doing some basic encoding, such as Manchester encoding, on the signal will improve robustness a whole lot. That will probably help when doing longer distance.

Are you willing to share the code? I am curious.

Again, nice work!

Anders
24  Community / Exhibition / Gallery / Re: Yet another Humidity and Temperature logger on: January 06, 2013, 08:05:07 am

on the other hand the analog hygrometer agrees on the new value.

*confused*
25  Community / Exhibition / Gallery / Re: Yet another Humidity and Temperature logger on: January 06, 2013, 08:02:28 am

.... and there I jinxed it *sigh*

Went back to upload the latest version of the data file (have it running) and then I see a sudden jump of almost 10% relative humidity!
Checkout the jump at 12:34 http://wohnung.se/arduino/hygrometer/data.html

This is 35min after I closed all windows and everything should be stable really.

Need to take a look at the debug printouts to see what is going on.

Regardless, it works a lot better than before.

Anders

26  Community / Exhibition / Gallery / Re: Yet another Humidity and Temperature logger on: January 06, 2013, 07:45:54 am

Success! :-)

I did some reading and some thinking to understand it on my own and came up with a slightly modified implementation from your code hint, but basically it is the same (2d interpolation).

Did a test run, including a big ventilation of the apartment (opening all windows) and kept a manual log from my reference setup (analog hygrometer and digital themometer) and it looks really good! The setup keeps within +/- 0.4C from the reference thermometer and a few % from what the analog hygrometer shows.

The new graphs are available on the same URL as before: http://wohnung.se/arduino/hygrometer/data.html

With the old approach, I would get strange bumps in the reading while ventilating and in the settling period following that. I guess because I would jump between temperature rows in the lookup table as the temperature dropped and rose again.


Thanks again for your patience and helpful advice!

Anders




27  Community / Exhibition / Gallery / Re: Yet another Humidity and Temperature logger on: January 05, 2013, 10:16:16 am

Sure,
the URL to the lookup table is actually in the source code in the sketch, just by the lookup table itself. :-)
It's from the data sheet for the EFS-10 humidity sensor. Here: http://www.produktinfo.conrad.com/datenblaetter/150000-174999/156545-da-01-en-Feuchtesensor_EFS10.pdf

I got the sensor as a present and really don't know so much about it other than it being sold by Conrad.de. It is the first time I use it and I can't say it was very easy. I am not used to generating AC signals to drive a sensor and then having to work out the impendance of it from the (volt) value you get from analogRead() didn't make it easier. Now add 2d-interpolation to that and everything gets a little too complex for a beginner like myself.

The LM335 is a common and easy-to-use temperaure sensor in a three-pin transistor like package. Didn't give me any trouble at all and pretty much worked the first time I hooked it up.

I am trying to incorporate your suggestions now BTW. Will report back once I have it working, hopefully tonight.

Anders

28  Community / Exhibition / Gallery / Re: Yet another Humidity and Temperature logger on: January 05, 2013, 08:51:49 am
Hey,
great advice! Thanks!

I too have been thinking about interpolating in 2d, but made it a priority to get all moving parts working together first.

Good points about the small stuff as well. Will work them into the next version, as I implement you 2d suggestion.

Many thanks!

Anders
29  Community / Exhibition / Gallery / Re: Bitlash Commander: Web UI toolkit for Arduino on: January 05, 2013, 02:55:33 am

Nice work!

Seeing the thread above, I recalled a problem with node and serial port communication I ran into a couple of weeks ago.

It seems like node-serialport has some kind of issue on Mac OSX.
Reported here https://github.com/voodootikigod/node-serialport/issues/111

Could that be lawm's problem?

Anders
30  Community / Exhibition / Gallery / Re: BlinkIT on: January 05, 2013, 02:36:31 am
Nice!
please post the code and some more detail if you can. I am interested to have a look. Are you using any kind if encoding? Looking at the video, it seems like a long pulse high marks the beginning of transfer. Have you considered the issue of ambient light (daylight), or is it too early at this stage?

Anders
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