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1  Using Arduino / Project Guidance / Re: Interfacing 4x4 keypad using 5 arduino pins on: October 07, 2012, 05:53:20 am
This won't work. All I inputs to the multiplexer are undriven, all times, irrespective of key presses.
2  Using Arduino / Networking, Protocols, and Devices / Re: SNMP BER question on: March 10, 2011, 04:26:24 am
From ITU-T X.690

Code:
8.3        Encoding of an integer value
8.3.1      The encoding of an integer value shall be primitive. The contents octets shall consist of one or more octets.
8.3.2      If the contents octets of an integer value encoding consist of more than one octet, then the bits of the first octet
and bit 8 of the second octet:
           a)     shall not all be ones; and
           b)     shall not all be zero.
                NOTE – These rules ensure that an integer value is always encoded in the smallest possible number of octets.


3  Using Arduino / Networking, Protocols, and Devices / Re: SNMP BER question on: March 09, 2011, 05:04:00 pm
from RFC2578

-- hundredths of seconds since an epoch
TimeTicks ::=
    [APPLICATION 3]
        IMPLICIT INTEGER (0..4294967295)

so your tag is 0x43
and length and value are encoded as implicit INTEGER
i.e. MSoctet first, minimal number of octets, two's complement
4  Forum 2005-2010 (read only) / Interfacing / Re: plug in an electric bell? on: August 27, 2010, 10:39:30 am
I think that the continuous ring electrical bell ( the second link in the original post) works by passing the solenoid current through the hammer and interrupting that current when the hammer reaches the bell, making it to release and then again activate and so on. If that's true, you could modify the wiring so that the solenoid is exclusively and directly controlled by the input voltage you provide. When appropriate voltage is applied the hammer is activated once (one ding) and when removed the hammer returns.
5  Forum 2005-2010 (read only) / Interfacing / Re: Buffers for ADC inputs? Increase precision? on: November 03, 2010, 02:55:00 pm
just keep in mind that the output impedance of an ideal voltage source followed by a potential divider is the parallel combination of the two resistors
6  Forum 2005-2010 (read only) / Interfacing / Re: Help. Mobile phone, audio jack, arduino and DTMF? on: October 19, 2010, 12:34:41 pm
Conceptually is far simpler. APRS is an application that is transported over AX.25, a packet networking (that is, there can be more than 2 nodes) protocol, which itself is transferred over VHF radio with FSK modulation.
DTMF is a representation of 16 values on one symbol but rather a signalling  system than a modulation method

Frequncy Shift Keying is a digital modulation method. The output is a wave. An incoming bit will make the output frequency to be f0 if it is 0 and f1 if it is 1. This output is sent over the 'channel' (VHF FM radio, audio cable, ...) to the other side physical entity, where  it is demodulated, i.e converted to the original bit stream - or at least attempted to since noise and gremlins never leave the channel. Then, bits are gathered to form bytes, bytes to form ... everything. I'm certain that wikipedians have alraedy written up the staff and far better than me.  smiley-wink

The channel and its gremlins is the thing that separates and joins you with the other side. The task is to tame the channel by feeding it with the properly tailored signal for efficient, error-free and appropriately fast communication. In the case of the audio cable connection for a low(-ish) data rate the things are much more comfortable than radio or telephony.

In fact perhaps you can do a pretty quick start by using the Tone library and a circuit similar to the one in bertos site (ommit the three of the four resistors R1-R4 since you have one output pin). Define your f0  and f1, and "send" a myfsk.play(1200,3) or a myfsk.play(1800,3) for a 0 or a 1. At the smart phone, have your application to discriminate between the two frequencies, set a bit upon the outcome, shift it in and wait for the next.  (at 3msec bit duration, you are at 333.33 baud - already higher than the Bell 103 and V.21 but behind 202 and V.22  smiley  )
7  Forum 2005-2010 (read only) / Interfacing / Re: Help. Mobile phone, audio jack, arduino and DTMF? on: October 18, 2010, 11:39:47 am
You can make a sketch in arduino communicate with a suitable application in your smartphone using audio channel and DTMF as  data transport, provided that the symbian environment (the operating system of the phone) allows a (user created? unsinged perhaps?) user space application to use the headset resource. I'm really not familiar with symbian development at all.

On the arduino side you can set up hardware and/or software to generate and decode DTMF tones. I think that a recent version of Tone library supports more than one simultaneous tone outputs and even (parts of) decoding can be arranged to be handled by software. Having said that, DTMF is not the best, eaasiest or  faster way to achive that communication (for example DTMFchips have guard times aligned with their original use at fixed line telephony of tens of msec limiting the number of symbols that can decoded in a given time frame). My choice would be in the direction of simple asynchronous FSK which you can relatively easily implement in arduino software - and suspectedly in symbian as well.

What you can't do is to produce DTMF tones in arduino and use them to dial numbers or send texts. The reason is that DTMF in not used for signalling in mobile telephony, which is purely digital and message based and the DTMF tones are transmitted only after the speach path is established.(there might be slight exceptions to this). You can still use them to control say appliances on the other end but after dialled and got answered by some other way.

You probably can do much more with AT commands over the digital connection the phone has but again goes to the specifics of the device and the os (though usb host functionality is not to be taken as granted at the arduino side)
 
I hope this helps

ps. it's L-R-mic-GND (1=L=tip)  http://pinouts.ru/CellularPhones-Nokia/nokia_handsfree_pinout.shtml
8  Forum 2005-2010 (read only) / Interfacing / Re: Digital Linear Gauge to RS232 on: September 27, 2010, 03:24:50 am
The sequence is in any case 000011111110 - i used nibbles for clarity and to be aligned with the data definitions.

Decimal digits are =<1001 and <1010, aren't they?  smiley

I agree that the original poster had a long way to go and an unfair (to me) pressure but perhaps (hopefully) the thread becomes of use to someone else.

BR


ps. I missed the four types of data frames in the data sheet. Where are they mentioned?
9  Forum 2005-2010 (read only) / Interfacing / Re: Digital Linear Gauge to RS232 on: September 27, 2010, 02:29:41 am
Isn't the sequence 0000 [end of one value data] --> 1111 [start of data] --> 1110 [start of value] --> MS decimal digit  (value < 1010) unique in the stream?
10  Forum 2005-2010 (read only) / Interfacing / Re: Controlling two cold cathodes - is this possible? on: September 12, 2010, 04:34:35 pm
inconsintency?
Finder part number "34.81.7.005.9024" is SSR
34.51.whatever is electromechanical
in case it is not clear to someone.
The finnish site link is to an SSR

i'd go to discrete too, for what it matters
11  Forum 2005-2010 (read only) / Interfacing / Re: Controlling two cold cathodes - is this possible? on: September 12, 2010, 02:49:24 pm
from page 3 of data sheet - see also p.2 (graphics broken, naturally )

Ordering information
Electromechanical relay (EMR)
 Example: 34 series slim electromechanical relay, 1 CO (SPDT) 6 A contacts, 24 V sensitive DC coil.
                                                                                A      B        C    D
                                                                                       0        1    0
                  3 4 . 5                1 . 7 . 0 2 4 . 0
                                                                 A: Contact material                 D: Special versions
 Series
                                                                 0 = Standard AgNi                   0 = Flux proof (RT II)
 Type
                                                                 4 = AgSnO2                          9 = Flat version
 5 = Electromechanical type
                                                                 5 = AgNi + Au (5 [ch956]m)                C: Options
 No. of poles
                                                                                                     1 = None
                                                                 B: Contact circuit
 1 = 1 pole, 6 A
                                                                 0 = CO (SPDT)
 Coil version                                                    3 = NO (SPST)
 7 = Sensitive DC
 Coil voltage
 See coil specifications
 Selecting features and options: only combinations in the same row are possible.
 Preferred selections for best avaliability are shown in bold.
   Type     Coil version   A           B           C           D
   34.51    sens. DC       0-4-5       0-3         1           0
   34.51    sens. DC       0-4-5       0           1           9
Solid state relay (SSR)
 Example: 34 series SSR relay, 2 A output, 24 V DC supply.
                 3 4 . 8                 1 . 7 . 0 2 4 . 9 0 2 4
                                                                                     Output circuit
 Series
                                                                                     9024 = 2 A - 24 V DC
 Type
                                                                                     7048 = 0.1 A - 48 V DC
 8 = SSR type
                                                                                     8240 = 2 A - 240 V AC
 Output
 1 = 1 NO (SPST-NO)
 Input circuit
 See input specifications
12  Forum 2005-2010 (read only) / Interfacing / Re: IR helicopter on: August 24, 2010, 05:10:02 am
http://www.rcgroups.com/forums/showthread.php?t=1231421
http://www.rcgroups.com/forums/showpost.php?p=15205498&postcount=95

i haven't gone through the whole threads but they seem to be a very very good starting point for what you want to do
13  Forum 2005-2010 (read only) / Interfacing / Re: Long distance detection on: July 29, 2010, 02:43:45 am
I completely agree with Richard on this.

What if the person at 150 feet triggers the gun and the unlucky one at 1 foot gets it on the stomach? or ... or ...

I wouldn't dare even to create a new directory with such a project unless in R&D of a defense company.
14  Forum 2005-2010 (read only) / Interfacing / Re: Single Circuit Crossfade with PWM and H-Bridge on: July 21, 2010, 06:20:16 am
some more rubbish ...
(this is pseudo-code )

void setup() {
notyetA1000 = true;
digitalWrite(A,LOW);
digitalWrite(B,LOW);
//other things
)


void loop()
{
setpointled1 = getsetp(LED1); //returns <1000
setpointled2 = getsetp(LED2);

elapsed= micros()-periodmark;

if notyetA1000 == true { //within the first half period
      if elapsed >  1000 {
            digitalWrite(A,HIGH);
            notyetA1000 = false;
                              }
      if elapsed > setpointled1 {
            digitalWrite(B,LOW)
                              }                               
      }
                        
else {
      if elapsed >  2000 {
            digitalWrite(A,LOW);
            notyetA1000 = true;
            periodmark = micros()
                              }
      if elapsed > setpointled2 + 1000 {
            digitalWrite(B,HIGH)      
                         }                              
      }

// do other things                        
                                    
}
15  Forum 2005-2010 (read only) / Interfacing / Re: Single Circuit Crossfade with PWM and H-Bridge on: July 20, 2010, 12:27:30 pm
Advantages? I don't know. He asked, i was intrigued somehow, i submitted an idea.
On the other hand, i think that all four requirements of the OP are covered.
If he finds it practical/suitable/viable/affordable/... that's even better - and my paranas deserve a treat for the inspiration.

cheers
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