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Hello everyone, okay?

I'm building a project for a college work and have some doubts.

The project needs to perform the following tasks:

1. Humidity sensors distributed transmit and receive data wirelessly. (~ 5 meters Arduino)

2. An Arduino receives all data.

3. Arduino data are stored in a central (PC database).

4. Distributed sensors can be powered by battery or voltage.

I wonder if you can just use an Arduino for the project, if so, what should I use the wireless transmitter system.

ps: Which model Arduino compatible to the project?

I appreciate the attention, sorry for English.

Vitor (:
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1. Humidity sensors distributed transmit and receive data wirelessly. (~ 5 meters Arduino)
How often? What is in between the sender and the receiver? What is your budget? How critical is it to not lose a reading?

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I wonder if you can just use an Arduino for the project
Of course.

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if so, what should I use the wireless transmitter system.
You need to answer the above questions, first. XBees are perfectly suitable, if a bit expensive. On the other hand, you wouldn't need an Arduino on the sender end, saving some money. Cheaper radios do not have microcontrollers built in, so you would need an Arduino at the sender end.

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ps: Which model Arduino compatible to the project?
All of them.
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How often? What is in between the sender and the receiver? What is your budget? How critical is it to not lose a reading?

Each time it was requested or every time.

My budget is not fixed, but do not intend to spend more than 120 dolars.

The data will be transmitted at all times, so losing data is not as important.

Do not understand the question than between the transmitter and receiver, but contend that the transmission will be wireless and will be less than 5m directly into the air.

If I use the XBee module on transmitters, will only need an Arduino with XBee to receive the data?

tks.
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$120 is going to limit you, at least depending on the number of sensors you plan on building at least.  If your Xbee costs $23, and your Arduino costs $25, that's almost half your budget for one of the sensors, and that doesn't include the sensor.  Power will probably cost you $10 to do it right. 

As for "Transmitting always"  that is not feasible.  Are you transmitting every 1ms, ever 10ms? every 1s?  every 1 min?  You cannot always be transmitting, especially if you intend to go off battery, and transmissions cost a lot of energy.  How often do you need to know when your sensors have new data?  Is there any reason you cannot just transmit every 15minutes?  Is your humidity changing that rapidly?
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As for "Transmitting always"  that is not feasible.  Are you transmitting every 1ms, ever 10ms? every 1s?  every 1 min?  You cannot always be transmitting, especially if you intend to go off battery, and transmissions cost a lot of energy.  How often do you need to know when your sensors have new data?  Is there any reason you cannot just transmit every 15minutes?  Is your humidity changing that rapidly?

If it is not feasible at all times, I will consider sending infoirmações every 30 seconds.
In the presentation of the project, it is impractical to wait 15 minutes for a change of status, so put a short period of time.
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$120 is going to limit you, at least depending on the number of sensors you plan on building at least.  If your Xbee costs $23, and your Arduino costs $25, that's almost half your budget for one of the sensors, and that doesn't include the sensor.
But, if using XBees, there doesn't need to be an Arduino at each sender. Nor does there really need to be one at the receiver, if all that it is doing is passing the data along to the PC.

OP: How many senders will there be?
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OP: How many senders will there be?

For the simulation to be valid, accurate data 4 humidity sensors at least.

One XBee can collect data from several sensors humidity?

if so, can I use two XBee and each with two sensors...

tks
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Code:
But, if using XBees, there doesn't need to be an Arduino at each sender

Arduino is a cheap commodity here when we talk about XBees , they already are  that coslty that cutting off the costs for a minimal or even moderately populated self made arduino will not benefit much, and yes if his code isn;t that much then he can use ATmega8s anyways.
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One XBee can collect data from several sensors humidity?
If you mean more than one, yes. If you mean two dozen, no.

Why don't you provide specifics? General questions are not helpful.
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The image below shows the basic idea of the project.
My goal is to not use many Xbee's because his price more expensive system.
If 1x Xbee can collect data from two humidity sensors, it would take only three Xbee for the entire system.

There is a need to use the Arduino as a receiver?

« Last Edit: March 31, 2014, 12:27:40 pm by vitorsn » Logged

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Hi,

You can try using 6LowPAN  for these purpose.  There are many variants available for AVR based solution.
For example Here is one Merkur board, I have experimented with it, it works at very low power.

Its an AVR module with  arduino booloader and for software it uses  Contiki OS and not Arduino
(The links are  in German)
http://osdwiki.open-entry.com/doku.php/de:projekte:merkur
Using with Raspberry Pi
http://osdwiki.open-entry.com/doku.php/de:ideen:rasperrymerkurboard

You can find the modules here
https://shop.dresden-elektronik.de/radiomodules/2-4-ghz/avr.html
There are other variants for ARM in the same above link

I made a video for basic 6LowPAN communication between two motes using REST APIs.


There are some libraries available for making it work in arduino such as
https://github.com/telecombretagne/Arduino-IPv6Stack

Or you can try Pinoccio https://pinocc.io/faq#faq-6LoWPAN.

Krishna



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Checkout PanStamps.
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If you are only going to be wanting to go about 5 meters then why not simply go down the BLE route or even the NF low power transmitters ... you can buy the NRF  ( http://www.ebay.co.uk/itm/271444747312 ) devices for a few $ and the BLE->UART bridges ( http://www.ebay.co.uk/itm/251310285396 ) for about $7.

The BLE->UART bridge will not require any libraries and there a a few out there for the NRF devices.

Connect them up to a few Arduino Pro Minis  ( http://www.ebay.co.uk/itm/231191125386 ) and you have a solution for < $50 for 3 nodes with a forth node  built up using the same combination and can be the bridge back to the PC using a USB->UART bridge ( http://www.ebay.co.uk/itm/261395201974 ) to the Pro Mini. This same cable will serve as the programming interface for the Pro Minis during firmware development.

Cheers Pete.
« Last Edit: April 05, 2014, 12:45:45 pm by Bainesbunch » Logged

EmbeddedAT .. From Concept to Prototype to Production

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