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New Opensource LRS Coming

Posted by Melih Karakelle on November 12, 2010 at 4:49am

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

flytron, lrs, long, range

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Comments

Lew Payne November 24, 2010 at 3:10pm

I just want to make you aware of these...

- Wide Band 450mW transmitter module
- UHF Multi-Channel transparent data link
- QPX1 2Watt VHF radio link transceiver
- 500mW VHF transceiver module

... any many other toys! Just scroll down this page link.
Andrew Dunlop November 24, 2010 at 1:53pm

@Dunk - another strategy for generating lots of PWM channels in hardware is to use just a single timer, but stagger all the pulses and demultiplex externally. AVRs have a suitable interrupt structure to allow reloading the PWM timer in the gaps between pulses. Using this technique it is possible to get 8 channels of hardware PWM per timer and with very light processor loading. Of course you do need some external hardware, but this is just a single IC.

Andrew.
Philip November 24, 2010 at 11:25am

Great project. It was time to prove alt the existing LRS way overpriced.
Brodilka November 23, 2010 at 7:14am

Congrats, Melih
It is possible to increase the number of servo ports? For example up to 14?
This will give more freedom for more complex systems FPV / UAV
And if possible to ensure the supply of power and distance for the PX / TX, it will be great!!!
dunk November 23, 2010 at 6:00am

have you considered using an AVR with more 10bit timers than the ATMEGA328P ?
this would allow you to do servo PWM in hardware leaving the microcontroller with far more time to do other things.

i use a single ATMEGA2561 to run a 2.4GHz module, measure current draw and battery voltage, act as an IMU and still have enough processing time left over for autopilot route planning.
this would not be possible if the AVR was having to do PWM in software.
on the down side, it would increase the cost a little....

i appreciate simple is good and this may be out of the scope of your project,
but versatile is good too.
a more powerful microcontroller that could do servo PWM in hardware and have some spare analogue inputs that could would allow aircraft battery monitoring would allow some powerful functionality.

dunk.
Russkel November 17, 2010 at 11:22pm

What's the chance of a range flight test? Setting ardupilot to return home when the telemetric data link drops out?

Also, can two sets of these (on the same frequency) operate within range of each other?
Melih Karakelle November 17, 2010 at 9:44pm

@Kamu

No, my 50mw video transmitter's range was around 1km. This is why I flight behind a car and folded phone line antenna for reducing OpenFARC output. I guess it's range more than 5km. Today We tested it's control capabilities. We will test the range in this week.
Russkel November 17, 2010 at 9:08pm

You say it is working away 1km without any problems, does this mean there are problems at distances higher than 1km?

Excellent work none the less.
Melih Karakelle November 17, 2010 at 9:35am

Today we tested the OpenFARC system for first time.
The platform was a disposable Depron plane, our FC480 camera and FTX50 50mW 2.4ghz video transmitter.
After first flight, we played with a funjet for testing high speed responses
Results:
- It's working from 1 km away without any problem when transmitter behind the car's metal body (antenna was a 17cm phone cable)
- Refresh rate and latency was similar with a 2.4ghz Futaba tx/rx
- We finished 3 hours flight and ground test without any problem

Next week i will order 4th generation PCBs for first release of OpenFARC system.
Thanks for reading
Sebastian Gralla November 16, 2010 at 6:40am

a version with ppm out instead of the servo channels would be good

really nice project :)