Hi;
I have a helicopter, which is loaded with some parts like GPS,Accelerometer, rpm counter, temperature sensor and a pic… I want to transmit this datas to my computer serial port.
What you recommend, which solution is the best? I think xbee is appropriate for me…
Is Xbee confidential(is it losting data?) and easy to programmin?
Thanks in advance!
Range?
Leon
Anyway helicopter isn’t seen after 100meters…
But if there wasn’t a big gap between long range and short range, I want to buy the long range module, when I bought…
fatal1ty89:
Hi;I have a helicopter, which is loaded with some parts like GPS,Accelerometer, rpm counter, temperature sensor and a pic… I want to transmit this datas to my computer serial port.
What you recommend, which solution is the best? I think xbee is appropriate for me…
Is Xbee confidential(is it losting data?) and easy to programmin?
Thanks in advance!
since you want to go to the PC, yes, I’d say that 802.15.4 without zigbee is easiest. The XBee series one are drop dead simple in this kind of application. Do a little number crunching to decide if you need the “pro” version which has about 60mW transmitter power whereas the non-Pro is about 1mW. The fading and error rates will be better, if your battery consumption budget can stand the higher power. It’s all about transmitter duty cycle - how many mA per hour consumed for all devices versus the battery capacity down to some voltage droop.
The ground side antenna is important: typical rubber-ducky antenna has poor vertical radiation. This is more important at 2.4GHz than the lower freqs used by R/C transmitters.
You can get 802.15.4 modules for 900MHz (US, 868 in EU), and they will do somewhat better than 2.4GHz. But the cost more and use more battery.
As to error correction: The 802.15.4 MAC layer has CRC error detectoin and error correction - though it uses an ACK for good frames and no ACK for errored frames. The receiving end has to timeout a missing ACK and retransmit n times. This time delay is adjustable and may be important. I’d suggest you code a simple protocol in addition: say one with message sequence number checking to detect lost frames (802.15.4 has that too, but its an option not usually implemented).
Thanks for your concern, I deceide to buy XBee Pro 60mW;
But It has three option about antenna;
-U.FL connection (I can’t see the U.fl antenna in sparkfun…)
-Chip Antenna
-Wire antenna
Which one is the longest range? And which one do you recommend?
Thanks in advance…
I’m in a hurry, please help…
For longest range i’d go with the wire antenna option. It should be lighter than a module with an external antenna…
Thanks for your answer.
ok, can I replace the wire with RPSMA connector to use an external antenna?
fatal1ty89:
“can I replace the wire with RPSMA connector to use an external antenna?”
What the 1500m range isn’t far enough?..
If you change anything on these modules, they will not retain their FCC certification…
And having an external antenna will add a bit more unnessercary weight to the (presumably model) helicopter…
If you use the U.FL module, you could use one of [these to change the socket…](Interface Cable RP-SMA to U.FL - 100mm - WRL-00662 - SparkFun Electronics)
My anxiety is how it can equal wire antenna and rpsma antenna?
All of them can transmit over 1500meter? I’m Sorry I 'm having difficulties to believe it=)
to get 1500m you will need the ext. ant. connector and a high gain antenna. Maybe on both ends.
I got 3/4 mile line of sight with two XBee Pros at 60mW. One had a chip antenna; the other had just 5.6dBi from an omni. There are lots of 14dBi patch antennas available from the WiFi world, such as hyperlinktech.com
you can easily calculate what power and antennas you need for distance x if you have line of sight. Google for a link budget calculator.