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46  Using Arduino / Project Guidance / Re: Sanity check for burglar alarm project on: June 28, 2014, 06:28:25 am
Quote
Yes but I2C is generally for inter-board communication or between ICs not long distance communications over cables.
Partly true. Depends on the cable you use. I have used I2c through a 100 ft. coax cable with no problem.


Did you run 2 lengths then, one for SCL, SDA, and a common ground tying all the RF shielding together or another configuration ?

Cheers Pete.
47  Using Arduino / Project Guidance / Re: Sanity check for burglar alarm project on: June 28, 2014, 06:23:14 am
Ok this might be a really stupid question, but since I am a complete newbie when it comes to RS485 I have to ask smiley

If I use something like http://www.ebay.co.uk/itm/WaveShare-RS485-Module-MAX485-RS485-TTL-Transceiver-Module-/141181191780?pt=UK_Computing_CablesConnectors_RL&hash=item20df0e0664 how do you connect several of them together, I assume you cannot use a regular Ethernet hub?

Correct, just because it has an RJ45 connector does NOT make it Ethernet, BUT it is used so that you can use standard Ethernet cables (cat 5 twisted pair) to connect them together with.

Are you based in the UK ?


Cheers Pete.
48  Using Arduino / Project Guidance / Re: simple break beam circuit using https://www.sparkfun.com/products/241 on: June 28, 2014, 06:17:55 am
"The penalty for forgetting OHM's LAW is a PIE in the EIR !
P(power) = I (current x E (voltage)
E (voltage) = I ( current)  x R (resistance)
( re- arrange expressions by dividing both sides by  one of the variables to obtain expression for another)
ie:
E=I x R
E/R = I/R x R
I = E/R


Ha ha I like it ....

I learned using the triangle method

         V                    W
     I   x   R           I   x  V     

Cheers Pete.
49  Using Arduino / Project Guidance / Re: simple break beam circuit using https://www.sparkfun.com/products/241 on: June 28, 2014, 06:13:45 am
I am a Blues fan as well. I used to see Albert & BB King live at the Philmore in San Fransisco. I only started learning electronics 35 years ago when I was a full time restaurant cook trying to cross-train myself in my off time. I started with RadioShack children's
electronics kits with the spring contacts that allow you to wire hundreds of different circuits (one at a time) without solder. I also used Heathkit Homestudy Electronics courses, but by far, the most useful medium were the 'cookbooks" , which are the electronics version of recipe books , that have an introduction to the theory , then the schematic and some paragraphs that amount to application notes. When I started, I did not know how to read schematics, but I quickly learned. I think that trying to encourage newcomers to electronics to remain ignorant of schematics is detrimental to their advancement. If you were talking about children playing with toys it would make perfect sense, but to encourage adults to "play" with electronics and not worry about "how " a circuit works is not only counter productive , it is just plain stupid. If the individual is Bank VP who wants to build his own security system as a hobby , then I suppose it makes sense.  Would you try to teach someone how to overhaul an engine without knowing how to read a mechanical drawing ? Sure, that is totally possible and probably happens every day, but not because they choose to do it that way. If they are not using drawings it is probably because they don't have them. The forum is inundated with a plethora of people who get into the arduino hobby with the attitude that "It's Shake & Bake , anyone can do it !" and the Instructables , though very informative , propagate this attitude with their reputation for not including schematics. Admittedly some do include schematics, but the majority don't.  I find this attitude to be idiotic. A schematic is really not that hard to understand. You really only need to learn 20 or 30 symbols to get by.  Yesterday some guy posted because he was having trouble with a pot (potentiometer). Since his problem seemed to be hardware related, I naturally asked him what value pot he was using. His reply was "What do mean what value ? It's a pot ! I'm reading 0 to 255 on the serial monitor !"  Yes, you can use an arduino if you are ignorant and can't read a schematic. Can you be productive ? Probably not.  Building electronic kits from diagrams is perfectly understandable for children, for several reasons. Should an adult follow that approach ? Well, that depends. If they are unable to focus on details then yes , probably they should. Would they be more productive and versatile if they knew how to read and draw schematics, probably. At the end of the day, when you make excuses for not learning, you only hinder your progress. Nothing you can say would support the case that it is better to NOT know how to read and draw schematics. So , I am glad that you had fun with your kits, but don't encourage newbies to remain ignorant because you were able to do something 45 years ago without knowing how to read schematics. I was a cook. I did not even know WHAT a resistor or capacitor were when I started. If you named ANY electronic component when I started, I could NOT have told you what it was or did, yet in one year, I not only learned how to read and draw schematics, I built about 300 circuits (some soldered) , including op amp circuits, power supplies with fold-back current limiting, audio amplifiers, digital sequencers and more, all because I learned to read and draw schematics. If you want to help the OP, tell him you think you would have learned faster if you knew how to read schematics. That's what he needs. He needs a reason to do it, not an excuse to avoid it.
Cheers !,
Robert
Schematic Enforcement Agency

I am not denouncing learning theory, but we are subscribing and answering questions on an Arduino forum and not an electronics hobbyist forum.

Arduino is by its very nature a "hacking" platform. It was introduced to bring electronic project building to the masses and has succeeded in doing this very well. We get a lot of Newbie question on here because it is a hacking platform. It does allow you to expand your knowledge of electronics and for that I am in agreement with you that once past the initial "hacking" stage then theory is a must.

Most of the newbie question on here are from people dipping their toes in the water to learn to swim. Demanding that they jump in the deep end will put many off. That would be both a shame an in contradiction to the whole Arduino Ethos.

I dont think we will ever agree on this point but it is making for a good debate.

Cheers Pete.
50  Using Arduino / Project Guidance / Re: Sanity check for burglar alarm project on: June 28, 2014, 05:36:12 am
With I2C you don't have to daisy chain them. One master and the rest slaves. In fact 1 or more masters and slaves. A board can be a master and a slave. Very flexible and easy to set up. I'm using this set up for a three board weather station. Also a alarm system that uses a land line phone.
 

Yes but I2C is generally for inter-board communication or between ICs not long distance communications over cables. You could get some line buffers in there but that would negate the design of the system the OP is proposing.

Cheers Pete.
51  Using Arduino / Project Guidance / Re: Sanity check for burglar alarm project on: June 28, 2014, 05:27:18 am
@Pete,
So we actually do agree on something.  smiley-grin

Robert

@Rob

I think you may find that we agree on quite a lot eventually smiley
52  Using Arduino / Project Guidance / Re: Sanity check for burglar alarm project on: June 28, 2014, 05:15:29 am
The serial link on the Arduinos is at TTL voltage levels. This is not good for long distance runs. You really should be considering a balanced line  protocol like 485. This will give you better noise rejection as it can travel through a cat 5 twisted pair and cancel out noise from the line.

take a look at this http://en.wikipedia.org/wiki/RS-485

and then this https://www.sparkfun.com/products/10124

Cheers Pete.
53  Community / Gigs and Collaborations / Re: Arduino developer needed for POC project. on: June 28, 2014, 02:01:49 am
Hello Corey,

I have sent you an email introducing myself.

Cheers Pete.
54  Using Arduino / Project Guidance / Re: Speed and recognition on: June 27, 2014, 04:28:24 pm
If you are feeling adventurous you can also adjust the size of the serial receive buffer in the support classes. Something i have done a few times when i had large bursts of data with time to read and clear the buffer between bursts.

Cheers Pete.
55  Using Arduino / Project Guidance / Re: Make a USBTiny with Arduino? on: June 27, 2014, 04:18:56 pm
OK so that is easy smiley

tha ISP header you see will be the same as the ones on the Arduino boards. It has become a standard

type "arduino isp header" into Google and look at the images .. lots of wiring examples there for you.

this is what you are looking for

http://letsmakerobots.com/content/make-arduino-isp-programmer


Hope this helps
56  Using Arduino / Project Guidance / Re: Problem programming ATtiny85 on: June 27, 2014, 03:52:46 pm
(PS-I never say "Cheers " to anyone who is at their wit's end)

I say "Cheers" to Every one no matter what end they are at smiley

Cheers Pete.
57  Using Arduino / Project Guidance / Re: Problem programming ATtiny85 on: June 27, 2014, 03:42:49 pm
where are you getting the attiny definition files from for the IDE

is the ATtiny listed as a board in the IDE ?

I Presume you have followed this link through ?

http://www.instructables.com/id/Using-the-Arduino-Uno-to-program-ATTINY84-20PU/


Cheers Pete.
58  Using Arduino / Project Guidance / Re: Make a USBTiny with Arduino? on: June 27, 2014, 03:33:17 pm
Hi WIll,

sure you can, there are a lot of good references to do this and the programmer is listed as "Arduino as ISP" under the "tools-> programmer" in the Arduino IDE.

here is the link http://arduino.cc/en/Tutorial/ArduinoISP

Cheers Pete.
59  Using Arduino / Project Guidance / Re: simple break beam circuit using https://www.sparkfun.com/products/241 on: June 27, 2014, 01:40:36 pm
Amen smiley
60  Using Arduino / Project Guidance / Re: Speed and recognition on: June 27, 2014, 12:49:36 pm
I am not sure i fully understand this question.

What is it you are trying to communicate between the device using xbees

how are you measuring the speed to get your 5-10 MPH window

what is the sweet spot that occurs in 1.5 seconds ?

Analogue/digital it is all the same in programming world. since the ADC takes your analogue signal and turns it into a digital representation anyway.

Can you try and re-explain what it is you are trying to do

Cheers Pete.
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