Hi Guys,

I just finished the test of our new opensource long range system modules.
This modules 3th generation and i guess i should design 4th generation before publishing them.


I'm using RFM22B radio modules and ATMEGA328P chips on Rx and Tx.
Rx modules including 8 channel servo ports and RS232 for telemetry uplink

Tx modules including PPM-Input for analog servo control and RS232 for Computer based controls and Telemetry downlink.


System range will be around 4-5km.

Firmware Upgradeable over RS232.


Ground tests was unbelievable, it's working around 500 meters into the city (after 20+ concrete building)

I will share the flight test results, sources and schematics soon.


If you have any idea about design and inputs, please share with me before 4th generation's production..

Thanks for reading

Melih

Views: 2836

Comment by tycinis on November 12, 2010 at 6:08am
the price will be the same compare to the others LRS 433mhz system ?

T3
Comment by Mark Griffin on November 12, 2010 at 7:00am
Hey great idea, Melih.
The RFM22B modules are ideal for this purpose. I like the fact that they can be programmed to operate in either the 400 MHz band or the 900 MHz band. +20 dBm is sufficient tx power for this purpose.
Comment by Renato Aranghelovici on November 12, 2010 at 7:13am
Congrats, Melih
I always wait this day, when someone will show that the currently LRS systems are way overpriced, and I am sure there is no competition between them, given how they all keep the prices so high.
The total cost of manufacturing this system is under $30, the modules are $6 each, and the others components can't be more than $15.
Based on the modules specs, of 17dB power ad -118dB sensitivity, 2dB stock antennas, and 15dB fade margin, at 433Mhz you should be able to reach 77km, at 868 half this distance.
So, I think your 4-5 km estimation is way too conservative.
Comment by Marco Glattfelder on November 12, 2010 at 7:26am
Wow: These are a real alternative to the expansive xbee pro modules.
I was looking at these modules too, but a bit aware about the tricky integration. There is the RFM12BP with +27dBm too. What about that? With +20dBm ist still a 10% duty cycle restriction?
Comment by DaveyWaveyBunsenBurner on November 12, 2010 at 7:53am
Now that's nice! Cannot wait to see it released!
Comment by Renato Aranghelovici on November 12, 2010 at 8:04am
Melih, please consider design of Tx module as a Futaba / JR compatible module board.
Comment by Ron Jacobs on November 12, 2010 at 8:35am
Please keep in mind any laws, regulations and guidelines that regulate RC flight in your areas. Many jurisdictions do not allow flying above certain altitudes, beyond set range and most require line of sight and ground operator controllability at all times.


"Safe: We follow the current interpretation of the FAA guidelines on small UAVs. Recreational use (non-commerical), under 400 ft altitude, line of sight, "pilot in the loop" and onboard safety systems that always allow for manual control in the case of malfunction. We're building experimental platforms that demonstrate autonomy and the capacity to do real useful UAV work, but we test them in controlled settings. If you want to fly miles out of sight or map cities, we're going to assume you've got the proper FAA clearance or we don't want to know about it."
Comment by Russkel on November 12, 2010 at 9:14am
I am excited about the release of this. Cheap and open. What could be better?
Thanks for your work on this.
Comment by Jhon on November 12, 2010 at 11:05am
Try to put some kind of filters in the receiver, there is lot of RFI from camera, ESC, voltaje regulators and so on... try to minimize the impact in the receiver,

WIch is the output power of the transmitter?

If you could sell in the a Futaba/JR module would be perfect, just plug and play,

What kind of safety features foes it have? FHSS maybe?
Comment by Ivan on November 12, 2010 at 2:53pm
Count me in as a kit buyer, pls. Always thought that $100 or $120 for XBee setup is far too expensive.

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