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[on:]

Hi all,

I am new to arduino and i must say that the sheer amount of modules is overwhelming. Before i spend too much money on modules i don't fully need i wanted to ask you for advice.

For my thesis project i need to capture accelerometer data from persons when they are in conversation. Since the conversations will be on the street I need the data transmitted wirelessly.

First of all i need 6 accelerometers. I won't need a gyroscope per se, so i go for: http://iprototype.nl/products/components/sensors/ADXL345

The data from the accelerometer i need to read with an arduino board, as i understand from http://arduino.cc/en/Tutorial/ADXL3xx. What is the difference between the Duemilanove and the Arduino Uno? Except for the price?

Then i need to send this data to my laptop, for monitoring and storing. This i can do by usb cables but i prefer a wireless connection. Herefore i would need a wireless Xbee shield, is this correct? Or are there other options such as the arduino Bluetooth Board? But the BT board is quite expensive and i don't think i will use its full potential. I read that an XBee shield is the best value option, see http://arduino.cc/en/Main/ArduinoWirelessShield. But do i need a receiving unit as well? And if yes, would i need 6 or can just 1 receiver work for all accelerometers?
Also, would the Xbee requiere that there is a wifi connection available?


Please share your thoughts on this!

bye
jorrit

[Reply #1 on:]

What is the difference between the Duemilanove and the Arduino Uno? Except for the price?

The type of USB-to-serial converter chip. Does it matter? Probably not.

Herefore i would need a wireless Xbee shield, is this correct?

An an XBee to put on the shield.

But do i need a receiving unit as well?

Yes.

And if yes, would i need 6 or can just 1 receiver work for all accelerometers?

You are connecting the accelerometers to the Arduino, not the XBee, aren't you? If so, then you need one XBee with shield per Arduino.

Also, would the Xbee requiere that there is a wifi connection available?

No. XBee is NOT WiFi.

[Reply #2 on:]

Thanks for the reply,

so i think i'll take the 2009 board then. In order to connect sensors to the board i would need to solder or use a breadboard right?

And if yes, would i need 6 or can just 1 receiver work for all accelerometers?

You are connecting the accelerometers to the Arduino, not the XBee, aren't you? If so, then you need one XBee with shield per Arduino.

But would i need also one receiver unit on the laptop side per accelerometer?

thank you

[Reply #3 on:]

In order to connect sensors to the board i would need to solder or use a breadboard right?

No, but a breadboard makes the wiring a lot neater.

But would i need also one receiver unit on the laptop side per accelerometer?

Draw yourself a picture. There are 6 accelerometers connected to one Arduino (maybe - you need to see if that is even possible. Which pins do your accelerometers connect to?). The Arduino then sends data to one XBee to transmit.

It should be trivial to figure out how many (1, one, less than 2, just slightly more than zero) receivers you need.

[Reply #4 on:]

In order to connect sensors to the board i would need to solder or use a breadboard right?

No, but a breadboard makes the wiring a lot neater.

But would i need also one receiver unit on the laptop side per accelerometer?

Draw yourself a picture. There are 6 accelerometers connected to one Arduino (maybe - you need to see if that is even possible. Which pins do your accelerometers connect to?). The Arduino then sends data to one XBee to transmit.

It should be trivial to figure out how many (1, one, less than 2, just slightly more than zero) receivers you need.

I will NOT be connecting 6 accelerometers to one arduino. Each sensor has it's own board. Thus, on each board, there should be one xbee shield and a xbee transmitter. From the documentation i found that one receiver can receive from more than one transmitter.

[Reply #5 on:]

I will NOT be connecting 6 accelerometers to one arduino. Each sensor has it's own board.

That wasn't clear from your first post. So, you plan to equip a person with 6 Arduinos, each with an XBee shield and XBee and accelerometer. That will get expensive.

From the documentation i found that one receiver can receive from more than one transmitter.

Yes, as long as the amount of data is manageable and there is some way to identify which accelerometer/Arduino/XBee the data is from.

[Reply #6 on:]

Ok thank you

i'll go ahead and order myself some!

[Reply #7 on:]

Hi,

Please let us know how it is going.
I have tried to use the xbee shield myself, but I found it not very easy to make it send data in a fast manner.
Is it working nicely for you?

-daft

[Reply #8 on:]

Hi,

i did order the adxl345 but from china. Although they physically worked, their output was inconsistent. Eventually i went for the adxl335 (analog).

Also, i went for local datastorage on a sd card. Could have been nice to be able to monitor the incoming data remotely but i didnt have time to implement (and program) a xBee.

I do use the mega ADK, so i might use my phone for transmission. Than i could use wifi which will be fast enough.