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826  Using Arduino / Sensors / Re: i2c read failed: 4 with mpu6050 and saberthooth 2x25 on: May 20, 2014, 11:37:40 am
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Yes there is a logic analyzer for the i2c communication on the begining of the code that forbids the code to move on unless the comunication is established.

You may have misunderstood the question.   A logic analyzer is a kind of oscilloscope which will display the waveform of your I2C bit communications.
827  Using Arduino / Sensors / Re: Maximum number of DS18B20 on one pin on: May 20, 2014, 11:32:58 am
These gadgets each have a 48 bit address.  Every device that comes from their factory allegedly has a unique 48 bit ID.    That is billions of ID numbers.

If you have, say, 10 ( or 50 ) devices on your network,   the first thing you have to do is find out what the numbers of your 10 ( or 50 ) devices are.   Your master device ( ie. your arduino ),  has to look for all of the BILLIONS of 48 bit addresses,    and notice which 10 of those possible billions of addresses responds.   Once it has those 10 ( or 50 ) addresses,  it keeps them in a table  and only tries to talk to those specific addresses.

Suppose you have a cell phone and 50 friends and you lost all your friends number.    You could dial ALL THE CELL PHONES IN THE WORLD and ask them if they are your friend,  and then write down the numbers of the 50 that you find.   This would be an impractical process.   Fortunately,  they have a slightly smarter scheme,  but it still takes a fairly long time.  They use subsets of the 48 bit addresses to save time.
828  Using Arduino / Sensors / Re: Maximum number of DS18B20 on one pin on: May 20, 2014, 11:09:27 am
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allowing up to 75 devices to be found per second

That quote is concerned with the rate at which devices can be found by address detection.   And it is a RATE,   not a number of devices.   If you can find 25 devices in 1/3 of a second,    or 225 devices in 3 seconds,   you get that detection RATE.    It doesn't mean that you can actually have 75,  or 25,  or 225 devices on your network.    The address detection process for the 1-wire scheme is a separate issue from actually reading data from the sensors.

There is no specific limit to the number of devices,   it is determined by electrical issues related to the capacitance and impedance of your wiring.   It varies depending on how long your wires are.

Read this

http://pdfserv.maximintegrated.com/en/an/AN148.pdf
829  Using Arduino / Sensors / Re: MMA7331L 3-axis mio robot Accelerometer on: May 20, 2014, 10:59:07 am
It is an analog device.   You connect the three outputs to three analog inputs on your arduino  and read the values using analogRead()
830  Using Arduino / Sensors / Re: Looking for high accuracy temperature sensor on: May 20, 2014, 07:27:23 am
You are going to have to deal with the issue of the actual physical contact between the snow and the sensor.    If the snow is very dry,   you will be measuring the air temperature.   And if the snow is a bit wet,   you will be measuring the water temperature,   which is going to be 32F /  0 C  almost by definition.
831  Using Arduino / Sensors / Re: Hook up wires - cost on: May 20, 2014, 07:21:15 am
You'd need to consider all the issues about running low voltage sensor wires that far,   but you can get ethernet cables with more than 4 cores in them for well under a $1 a metre.
832  Using Arduino / Programming Questions / Re: Can't track down <Tracker.h> on: May 20, 2014, 07:17:09 am
Ticker or Tracker ?

Go back to the website you got the program from,   and read it more carefully.
833  Using Arduino / Programming Questions / Re: Need help on the IF-statement on: May 20, 2014, 07:15:02 am
You've got mismatched parentheses in your if statement there.
834  Using Arduino / General Electronics / Re: Car battery/alternator supply to 5V regulator- capacitors? on: May 20, 2014, 01:29:04 am
Supplying from a vehicle battery,  you mainly need the capacitor not to deal with ripple in the supply,  nor with the impact of transient demands from your device,    but with electrical noise from other things in the vehicle.

This typically seems to mean using several different capacitors targetted at those different objectives/problems.  If you look at previous threads,  you will see useful advice from people who are experts.

If you use a regulator to convert 12v to 5v,   you are throwing away 60% of the energy in the regulator, which is not only wasteful but will cause it to overheat.   You might want to get a 12v to 5v  converter,  which is more efficient.
835  Using Arduino / General Electronics / Re: Don't Understand How To Operate AdaFruit Pump on: May 20, 2014, 01:21:58 am
Is google broken in your country ?

http://arduino-for-beginners.blogspot.com.au/2011/03/controlling-12v-dc-motorfan-with.html

http://www.instructables.com/id/Use-Arduino-with-TIP120-transistor-to-control-moto/

http://forum.arduino.cc/index.php/topic,12237.0.html

https://learn.adafruit.com/adafruit-motor-shield-v2-for-arduino/powering-motors

http://forum.arduino.cc/index.php/topic,11860.0.html
836  Using Arduino / Programming Questions / Re: Multiplexing multiple analog values on: May 20, 2014, 01:16:21 am
The three selector pins determine which of the multiple inputs of the chip,   connects to the output of the chip which feeds into your arduino a/d input.

You control the three selector pins to either high ( 1 ) or low ( 0 ) with three digital outputs of your arduino.   These three pins form a 3 bit binary number which has the values  000 001 010 011 100 101 110 111   which are the binary numbers for 0 to 7   which selects which of the 8 analog inputs on the chip you currently want to measure.
837  Using Arduino / Motors, Mechanics, and Power / Re: Controlling race car fuel pumps on: May 20, 2014, 01:11:18 am
To control the pump,   you will first need to determine what sort of electric motor the pump uses.
838  Using Arduino / Sensors / Re: Value of an sensitive Analogsensor changes heavy with other power sup. than USB on: May 20, 2014, 12:56:51 am
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I don't know what a Sterling engine is .

He wrote Stirling engine,  which,  perhaps surprisingly for the idiots who post here asking dumb questions, is correct.

Is google broken in your country ?
839  Using Arduino / Sensors / Re: accelerometer MMA7455 on: May 20, 2014, 12:53:40 am
There is a very clear diagram in the Parallax document for the module,   showing you how to connect it.

I don't know what pins the Due uses for I2c.    Is google broken in your country ?

Try this.   Google   "   Due  I2C "   and look at the first 20 web pages that appear.
840  Using Arduino / Sensors / Re: Help Using Sparkfun Accelerometer MMA7361 on: May 19, 2014, 01:25:50 pm
Perhaps if you understood what those pins did,  you would realise that for any normal use,   you would not want to use them.
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