Show Posts
Pages: [1] 2 3 ... 6
1  Community / Exhibition / Gallery / Re: Made my own TwitterClient and I think it's better than the example one on: January 30, 2013, 05:23:18 am
Is there also a way to display my twitter feed (to display tweets from those I'm following)?

What you are looking for is the Home Timline
https://dev.twitter.com/docs/api/1/get/statuses/home_timeline
2  Community / Exhibition / Gallery / Re: Made my own TwitterClient and I think it's better than the example one on: January 29, 2013, 10:18:16 am


Code:
Good point, but sometimes it's just fun to have all in one solutions.

That is true and fun is one of the most important factors to consider. Why else would one have an Arduino hobby?

3  Community / Exhibition / Gallery / Re: Made my own TwitterClient and I think it's better than the example one on: January 29, 2013, 05:17:54 am
Nice work and thanks for sharing!

I have been playing with a similar idea for control purposes, but never actually built any of it.

A trick I find could help a lot to simplify the on-board Arduino logic would be to put a service in-between the Arduino and the Twitter API to act as a proxy and format translator.

The idea would be that you can use the right tool for the right job. Calling a REST webservice, parsing the results and doing something with the data is a piece of cake in most "internet languages", like Java, JavaScript, Ruby or PHP. With a such a proxy in place, you could re-format the response from Twitter into something very Arduino-friendly to save valuable CPU and RAM. It would also give you a separation of concerns and provide a place to add more advanced features like caching of results and adding in more sources without having to change the Arduino program.

Hosting of the translator proxy could be done on a server of yours, or on an application hosting service like the examples below.
http://www.heroku.com/
or http://nodejitsu.com/

Anders
4  Community / Exhibition / Gallery / Re: Manchester encoding library for RF links. on: January 25, 2013, 03:08:21 pm
Thanks,
I figured so.

Have the new mchr3k version running now. Had some trouble getting it to work as his example code does not compile... :-/

On the other hand, most of them were minor errors.

Have put together a rig with a laser and a photodiode and sending Manchester encoded data across. Too bad it doesn't decode at this point. Need to do a whole lot of debugging now.

Anders
5  Using Arduino / General Electronics / Re: Help calculate Rb for controlling laser using transistor on: January 20, 2013, 11:22:36 am


The working circuit:


6  Using Arduino / General Electronics / Re: Help calculate Rb for controlling laser using transistor on: January 20, 2013, 11:13:40 am
Ok,
so the datasheet for the laser module says
Working current: Min 10mA, Typical 20mA, Max 25mA

This gives me:
  • Ic = 20mA = 0.020A
  • Ib = Ic/10 = 0.002A
  • Rb = Vs/Ib = 5/0.002 = 2500 Ohm

Tried with a 2.7k Ohm and nothing happened.

Then I put in a fresh transistor, figuring I might have blown the old one after all the experimentation and it WORKS!

Where did you the magic number 10?
The datasheet for the transistor says hFE DC current gain 200 (minimum).

Many thanks!

Anders
7  Using Arduino / General Electronics / Re: Help calculate Rb for controlling laser using transistor on: January 20, 2013, 10:39:48 am

Hi,
yes, the laser module is 5V compatible (says 4.5V typical) and it lights up when connected directly over the 5V source.
It is one of these: http://www.seeedstudio.com/depot/5mw-laser-module-emitter-red-point-p-72.html?cPath=156_161

The 5V comes from a breadboard power supply.
http://www.seeedstudio.com/depot/5v33v-breadboard-power-supply-p-566.html?cPath=155

It is very strange, I too noticed the pinout and I am pretty sure I have it right.
I also guesstimated the same range as you, but I have had no luck. Tried the following values for R1
39 Ohm
175 Ohm
1K Ohm
10K Ohm

Maybe I managed to blow the transistor... need to switch to another one to double check.

Can't figure out why it's not working. Must be something silly.

Anders



8  Using Arduino / General Electronics / Help calculate Rb for controlling laser using transistor on: January 20, 2013, 09:51:24 am

Hello,
I am trying to use a BC547B NPN transistor as a switch to control a 5mW red laser, but I can't get it to work.

I believe it is because I have the wrong resistor to control the current on the base.

Does anyone here know how I can calculate R1 in the sketch below?
Please ignore the laser component name (QED123), it is just a side effect of picking a random LED component to symbolize my laser.




I am unfortunately stuck. Have tried random values for R1, but no luck.

Anders
9  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

10  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
11  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.

12  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

13  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
14  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






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

Thanks!,
will have a look at the code.

Anders
Pages: [1] 2 3 ... 6