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1  Using Arduino / Networking, Protocols, and Devices / Re: A wifi shield you will recommend on: July 08, 2012, 06:10:00 am
Just found that all shields and breakout modules can be categorized by the chip:
1. Microchip (many from China)
2. GainSpan (GS1011 or earlier)
3. Roving Networks (RN-171 or earlier)
4. WIZnet (e.g. dfrobot)
5. cannot figure out the chip on async_labs.

    Apparently, GainSpan has great documentation in their website and it can support ad hoc wifi network.
    Users please share your experience --
is ad hoc wifi supported by other chips?
(for GainSpan) if ad hoc wifi network is supported in Arduino's wifi libraries ?
if not, is it too wishful that it will be supported in near future?

-Frankie.
2  Using Arduino / Networking, Protocols, and Devices / Re: A wifi shield you will recommend on: July 08, 2012, 02:08:45 am
thanks to m_ri for the clever solution of using a cheap external wifi router. But it seems to the right time to buy a wifi shield.

the 'Hydrogen' shield is an interesting one.

For the use of RX/TX to talk in a wifi shield, is 'speed' the only drawback ? (when compared to SPI, IIC for example).

-Frankie.
3  Using Arduino / Networking, Protocols, and Devices / A wifi shield you will recommend on: July 07, 2012, 11:33:25 am
I want to add a wifi shield onto Arduino board for extra freedom (and the Arduino to react based on something retrieved from the Internet and some sensors) (no concrete plan yet).

There are quite a number of wifi shields (some went out of business such as CuHead). A fairly new shield based on WiFly RN-171 appeared in seeedstudio, looks promising.

I'd like to buy a wifi shield soon that is not (too) difficult to program, probably low-power too.

Grateful if you can share with me your experience and recommendation. Many thanks.

-Frankie
4  Using Arduino / Networking, Protocols, and Devices / (Ethernet) webclient on: June 02, 2012, 09:32:01 am
I want to read the local weather data (hong kong) for Arduino programming needs.
It seems to be a good start to base on sample WebClient code.

for http://www.hko.gov.hk/textonly/forecast/englishwx2.htm, it is supposedly easy.
i.e.
byte server[] = { 210, 0, 235, 4 } as www.hko.gov.hk
and ("GET /textonly/forecast/englishwx2.html HTTP/1.0");

    Unlike at least 5 other sites, this (210, 0, 235, 4) site simply refuses to give any text after 'connected'. Is it a special nature of this website that made the client.read() fail ??

note: http://210.0.235.4/textonly/forecast/englishwx2.htm is perfect with a browser.

    thanks for suggestion.
-Frankie.
5  Forum 2005-2010 (read only) / Troubleshooting / Re: AttachInterrupt() sample. what is expected? on: October 31, 2010, 01:20:32 am
thanks westfw

this sounds great (and practical). I shall find a PS2 connector to experiment with.

-Frankie.
6  Forum 2005-2010 (read only) / Troubleshooting / Re: AttachInterrupt() sample. what is expected? on: October 28, 2010, 10:46:47 pm
Thanks for naming the pin2.
After reading the document more closely, pin2 is the signal0. I click a +5V wire to it, and then I have the 'CHANGE' triggered. It's working now, though not in a way as I've expected.

I need to conduct more tests. AttachInterrupt should be very useful in my future projects.

If there're suggestions to demo AttachInterrupt() in a simple, yet practical way, I'd be happy to know.
-Frankie.
7  Forum 2005-2010 (read only) / Troubleshooting / Re: AttachInterrupt() sample. what is expected? on: October 22, 2010, 04:58:42 am
Hi pauls
 I merely want to see how the sample code works. Frankly, i don't know what to expect from that code.
  If there is another good and self-exPlanatory sample using AttachInterrupt(), i would love to try it out.

  Thanks
Frankie.
8  Forum 2005-2010 (read only) / Troubleshooting / AttachInterrupt() sample. what is expected? on: October 21, 2010, 10:58:09 am
I'm new to Arduino.
Using a duemilanove-compatible, running sample code as from arduino.cc demo code of attachInterrupt(). But I do not see anything interesting happening. (or no blinking)

Am I missing something? What's expected to be seen from that code?

Thanks.
-Frankie.
9  Forum 2005-2010 (read only) / Syntax & Programs / Re: logging 3 (slow) counters + SDcard on: December 01, 2010, 09:25:32 pm
Seriously. Many thanks.
I shall start with polling. (missing counts of 1-2% should be acceptable).
For 3-interrupts in Duemilanove, it looks like a huge challenge. I may try that later.
10  Forum 2005-2010 (read only) / Syntax & Programs / Re: logging 3 (slow) counters + SDcard on: December 01, 2010, 07:40:41 am
the 'hardware' is still in the lab and I will test it pretty soon. I have a feeling that the Pulse will last ~0.1s. My concern is more on the time Arduino spends to attend to SDcard and LCDdisplay, am I over-worried?

Just in case SDcard/LCDdisplay is not going to be a serious concern, can I just do simple Polling without extensive use of Interrupt ?

Many thanks.
11  Forum 2005-2010 (read only) / Syntax & Programs / logging 3 (slow) counters + SDcard on: November 30, 2010, 10:50:26 pm
I have 3 counters, they measure liquid flow. For each counter, a +5V signal should be triggered when a certain flow is met. Assuming that each physical count is 100ml, the counter shall show a signal at 100ml, 200mL, and so on. The goal is to use one Arduino to keep counts of all 3 counters.

Sub-goals:
(a) 3 counters * [ch61664] serial.print (PC); use PC to reset counter.
(b) 3 counters * [ch61664] LCD display; use PC to reset counter.
(c) 3 counters * [ch61664] LCD display + write to SDcard; on-board button to reset counts.
* with debounce

(Constraints/Requirements:
1. count frequency:  0.1min/count or lower.
but 2 counters may send triggers at the same time – but probably not within 0.01sec;
2. it is possible to have a low SDcard-writing frequency, say once in 6h. I'm expecting data interval = 10min, I will have 3 x 6 hr x 6set/hr = 108 data/write
3. not sure if LCD-display will steal time from the counters)

  I am quite new to Arduino programming. I'm not sure if I need interrupt or simple polling (noted a possible time-lag in writing to SDcard -- expects to be read by Excel in PC), and if I need to learn 'protothread'.
  Tons of thanks for pointing to a similar successful project with “multiple infrequent counters” or better.
12  Forum 2005-2010 (read only) / Syntax & Programs / Re: problem with interrupt and writing to sd-card on: November 30, 2010, 09:45:50 pm
i'm thinking of a similar project, but the frequency of writing will be a lot lower.
Did you try if a much-lower writing frequency can effectively lengthen the 2.xhr limit in writing to SDcard (and pin13dim) ?

-Frankie.
13  Forum 2005-2010 (read only) / Development / Re: compile library in IDE0016, but found in IDE0021 on: November 24, 2010, 08:57:40 pm
That's very helpful answer.

Take Wire library as an example, if I need to make a minor modification in it. The changed Wire.cpp (by me) will be compiled 'every time'. If header is also modified, do #include "Wire.h". Am I correct?
thanks PaulS.
-Frankie.
14  Forum 2005-2010 (read only) / Development / compile library in IDE0016, but found in IDE0021 on: November 24, 2010, 11:29:20 am
I was given a version of Arduino IDE v0016. It appears to be useful because code changed (e.g. Wire.cpp) will be automatically recompiled if the .o is deleted. But I do not find this convenience in the latest IDE v0021.

Am I missing something ? Wish someone can point me to a suitable document so that I can understand more about this in Development.

(probably, the Question can be rephrased as ... how to force _library_.cpp to recompile and be linked in v0021 ?)

-Frankie.
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