Wireless transmission using ZigBee

[gouthamp]

Dear all,

I am currently working on heart rate monitoring using photoplethysmography. Currently i have an analog output which gives the count of heartbeat. I need to ransmit this heart rate(analog data) to some other microcontroller through wireless. I would like to know whether i can use ZigBEE tehnology for this purpose.If its possible, please do tell on the available such ZigBee gadgets. Please do help me.

 

[raviypujar]

Depends on what kind of interface you want to use SPI, UART?
How much range you need to communicate?

You can use Xbee transceivers.
I use microchip modules MRF24J40MA and MRF24J40MB they have range from 400ft to 4000ft respectively.. and interface using SPI protocol..

If you want you can also use TARANG modules and Zigbee modules from Digi international.. they come with UART interface

 

[gouthamp]

Thank you sir for such an immediate response. I went through different ZigBee Transcievers. Fianlly i came to see about XBee Shields,XBee Modules which can be interfaced with Arduino. Could you please check whether it can be used for my purpose?

 

[bigdogguru]

If the application only requires a point-to-point topology rather than a mesh network, you may want to consider utilizing devices which offer only the 802.15.4 spec.

Devices like both the Digi XBee Series 1 and Nordic nRF24L01+ based modules offer the 802.15.4 or similar protocol, ideal for most point-to-point applications.

While devices which implement the ZigBee protocol, like the Digi XBee Series 2, were originally designed for the implementation of a more complex mesh network.

The Pro designation on either the XBee Series 1 and Series 2 indicates modules with expanded ranges.

You can purchase a pair of nRF24L01+ based transceiver modules with SPI interfaces on eBay in the $3 range, with free shipping to certain regions.

nRF24L01+ Ultra low power 2.4GHz RF Transceiver

**broken link removed**

If a UART interface is required, then Digi XBee Series 1 or compatible device maybe an option.

Breakout boards for the XBee series modules are readily available form many distributors, eBay and hobby suppliers:

**broken link removed**

BigDog

 

[gouthamp]

Will this be fine ??

Xbee shield over arduino
https://www.rhydolabz.com/index.php?main_page=product_info&products_id=1124

Xbee module over shield
https://www.rhydolabz.com/index.php?main_page=product_info&products_id=896

A pair of both (One as coordinator and one as Node). What do you suggest? I am using Arduino Uno

 

[bigdogguru]

The XBee Arduino shield should work fine.

However, the XBee module you've selected is a series 2, not a series 1.

The XBee series 1 modules are less expensive and are simpler to configure then the XBee series 2 modules.

In fact the XBee series 1 modules may not require any configuration before use and may connect right out of the box.

The XBee series 1 modules can form a virtual serial cable between the two Arduino UARTs.

I believe the following is an XBee series 1 with a U.FL for an external antenna:

Xbee 1mW U.FL Connection

Most major parts distributors carry them:

XB24-AUI-001

The part numbers for the series 1 all start with XB24 or XBP24 and do not follow with a BZ, they are also available with a wire or chip antenna if required.

Also, depending on the voltage range of the analog output of the sensor, you may not need an Arduino at the sensor point.

The XBees do offer an ADC input which can function without the aid of a microcontroller.

BigDog

 

[gouthamp]

Atlast I decided to proceed with the module:

**broken link removed**

Think it has ADC conversion .But does it belong to series 1 or series 2?


Moreoevr, if i do ADC conversion in my XBEE module, wat data will be transmitted wierlessly? Is it the analog to digitally converted data which is getting transmitted ? If so, Is it possible for me to program which digital data has to be transmitted in by the XBEE module? In other words, is it possible to program the XBee module so that i can transmit the required digital data by giving proper delay inside the XBee module itslef? Is it POssible?

Studying fundementals of XBEE.. Sorry if my question is meaningless.

 

[bigdogguru]

Although the photo is quite old, Maxstream was acquired by Digi several years ago, it appears the module in question is a series1.

It maybe a model XB24-AWI-001, although if it is the link provided to the datasheet and manual are to the wrong versions.

You might want to contact the business you intend on purchasing the device from and request the manufactures model number to be sure.

You also should be aware the XBees are 3.3v devices and are not 5v tolerant, so plan your project design accordingly.

You may also need either an RS-232 transceiver breakout board or FT232 USB to serial breakout board to allow you to configure the XBee for standalone configuration.

The ADC data is “represented as an unsigned 10-bit value right-justified on a 16-bit boundary.”

Concerning the ADC output the following links cover topic fairly well:



**broken link removed**

XBee Direct I/O with ADC

I found the following text quite helpful for series 1 only:

The Hands-on XBEE Lab Manual: Experiments that Teach you XBEE Wirelesss Communications

And the following for series 2 only:

Building Wireless Sensor Networks: with ZigBee, XBee, Arduino, and Processing

BigDog

 

[emontllo]

Although Zigbee is OK for this purpose you may be "overkilling" the application. There are more specific protocols such as ANT and ANT+ for this kind of applications, see:
**broken link removed**

 

[bigdogguru]

Although Zigbee is OK for this purpose you may be "overkilling" the application.

The XBee series 1 does NOT utilize the ZigBee Protocol, the XBee series 1 utilizes the simpler IEEE 802.15.4 spec.

BigDog

 

[gouthamp]

Is ZigBee protocol not same as IEEE 802.15.4??

 

[bigdogguru]

Is ZigBee protocol not same as IEEE 802.15.4??

No.

The are two different protocols, the IEEE 802.15.4 can be implemented without fees or royalties as it is an open protocol intended for simpler topologies like point-to-point or a basis to build more complex mesh network protocols.

The ZigBee protocol, on the other hand, its implementation is licensed by the ZigBee Alliance and is intended for the implementation of more complex mesh network, from your description of your project only a simpler point-to-point protocol is needed.

ZigBee Alliance



BigDog

 

[emontllo]

Is ZigBee protocol not same as IEEE 802.15.4??

IEEE 802.15.4 is a protocol that specifies only the physical layer and media access control (MAC). In the other hand ZigBee specifies a high level communication protocol.

Actually both ZigBee and ANT protocols are based on the same physical layer: IEEE 802.15.4.