PICkit2 - Tutorials, Experiments
PICkit 2 - Small size USB programmer
from Microchip.
How to use it as a demo device for
USB programming in C language
Java SE SWING JSR-296 Example
How to run background task in
JSR-296 SWING application
with 'busy animation' in the status bar.
Useful addition to Netbeans template.
Computer vision
Vision is the main sense of our robots.
See some Java algorithms we use
Tips-n-Tricks
Some advices about hardware and software tricks
PIC Programming
(firmware)
Assembler program for PIC16F628A
Communication program for sending
commands from cell phone to motors.
Driver for motor controller.
RoboHobbyPlugin
Open Source project on
SourceForge, Java brain
for the robot
In German
Short description of www.RoboHobby.com
in German
In French
Short description of www.RoboHobby.com
in French
In Spanish
Short description of www.RoboHobby.com
in Spanish
In Italian
Short description of www.RoboHobby.com
in Italian
In Russian
Short description of www.RoboHobby.com
in Russian
www.RoboHobby.com
What is the real connection distance of typical Bluetooth, Wi-Fi and ZigBee devices?
It is always interesting to know what is the real range of radio connection between
Bluetooth or Wi-Fi devices.
Usually you can find only some limited technical information in specifications and datasheets.
You can find some digits in decibels, but what this means to you?
What distance in meters will be OK for the normal connection in real environment?
Is the range is suitable for hobby robotics?
To check this we decided to do some tests with real devices on the real fields.
We had in our hands:
1) BlueTooth USB adapter Tekram TM-306 (Class 1, 100 meters range)
2) BlueTooth USB adapter BlueTake BT007Si
3) PDA HP IPAQ HX2790 (it has BlueTooth and Wi-Fi too)
4) Notebook 'Samsung R40'
5) Cell phone Siemens S75 (it has BlueTooth on board)
Important note: We do NOT used any antennas. Our goal was to test BlueTooth and Wi-Fi connections,
using the devices 'as is', without any kind of antennas.
We did tests on the field, on the empty territory with some bushes and trees.
The territory, where we did our outdoor tests of BlueTooth and Wi-Fi connections looks like this:
The results of the BlueTooth tests:
Test 1:
BlueTooth connection between notebook with Tekram TM-306 and PDA.
During the test PDA should transfer big file via BlueTooth to notebook.
The range of this connection was just 16 meters.
There is one interesting fact - when you put notebook right on the ground the range reduced.
It may be something about 10-12 meters.
But when you raise it up in your hands, for example 1.5 meters from the ground level,
the connection distance may become 14-16 meters.
Test 2:
BlueTooth connection between notebook with Tekram TM-306 and cell phone Siemens S75.
The range of this connection was just 14 meters.
As I suppose, BlueTooth receiver of Siemens S75 in not so good as BT adapter in HP IPAQ HX2790.
Test 3:
W-Fi connection between notebook and PDA.
During notebook sent pings to PDA.
The range of this connection was not so bad - 132 meters!
Again - when you put notebook right on the ground the range reduced,
when you raise it up in your hands, distance becomes much longer, then right from the ground.
Test 4:
Why connection between two BlueTooth devices is so short (16 meters)?
We had an idea to do one more test - connect two Class 1 BlueTooth adapters.
May be if we have Class 1 adapters (100 meters) on the both sides, things will be better?
We placed one Class 1 Bluetooth dongle was connected to desktop PC,
another was connected to notebook.
The range of this connection was 50 meters.
(Much better then 16 meters in the first test)!
Distance of ZigBee (Sun SPOT from SUN Microsystems)
Recently we have teased one more type of small devices - Sun SPOT from Sun Labs.
In official documentation it is declared that range is 10-75 meters.
In reality after some tests we have found that real measured range
in a building is about 8 meters.
Range in free air is about 20-25 meters.
But we should keep in mind, that Sun SPOTs can
work as a ZigBee-network devices and they can translate traffic to next device.
Using this feature you can create 'digital district' - small or big field (or building),
where you can place a lot of such a devices and
they can translate traffic and even calculate the best way for packets.
That means - if you have only two devices, it can work together and see
each other in a rang of 25 meters.
But (!) if you have 3 devices, they can cover distance of 50 meters,
4 devices can cover 75 meters, etc.
How to create hand-made Bluetooth and/or Wi-Fi antenna, using very simple materials and details.
Also it would be good to do test on the field radio frequency chips from Microchip and Atmel.
There are some RF Microchip chips, which have RF transmitters and receivers.
The chips are: rfRXD0420 Receiver Module, ZigBee RF Transceiver MRF24J40, etc.
It would be good to test their real connection range.
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