Originally Posted by Dennis Frie

Looks very nice.
What is the coil-formed copper in top-right? It looks a bit like an aircoil as part of the input-filter.

I finished a telemetry test that was able to send a string of data - and another sketch able to receive the data. But while testing I realized how bad the audio is on Lawmate and never really got any further. I have the sketch if you want to use it for anything.

The Aircoil is just a heat sink for the voltage regulator.

Please, may I have a copy of your work? I would like to experiment.

Thank you.

Originally Posted by rimshotcopter

The Aircoil is just a heat sink for the voltage regulator.

Please, may I have a copy of your work? I would like to experiment.

Thank you.

Oh heatsink - great
An aircoil would be pretty useless for that purpose.

I think this was the last sketch I played around with. At the moment I think it sends something like "ABCDEFG...", and the receiver prints the string when all characters have been received.
http://dl.dropbox.com/u/3947315/audio_modem.rar

Thank you Dennis, I really appreciate your help.

I have become very happy with the practice of using copper wire as a heat sink considering I have lots leftover from a home improvement project.



I picked up 100 5 volts regulators on ebay for I believe it was 10 bucks, I only needed a couple at the time. I would like the newer switching regulators but I am a strong believer in using what one has on-hand.

Conducted the very first test using an old Directv Dish Antenna adapted for 1.2Ghz FPV. Test looks very Promising. The TX(copter) was located in the front part of the house and the RX located in my workshop with a few concrete walls in between.

Dish for FPV usage Test 01 (0 min 58 sec)

Anyone looking for a gps module I can recommend this one -

http://www.ebay.co.uk/itm/Micro-GPS-...item27c5216357

Super fast shipping, good price and the seller also does one with a breakout board

/Frank

That was the very one i bought some month ago and is the very same the software was built around so its pretty much guaranteed to work so i would recommend it as well.

Originally Posted by rimshotcopter

Conducted the very first test using an old Directv Dish Antenna adapted for 1.2Ghz FPV. Test looks very Promising. The TX(copter) was located in the front part of the house and the RX located in my workshop with a few concrete walls in between.

http://www.youtube.com/watch?v=FBaWsjBz5IA

Looks interesting. Have you tested how narrow the beam-width is? But if you are just looking for a couple of hundred meters range, it shouldn't be necessary with directional antennas at all

Originally Posted by rimshotcopter

I have become very happy with the practice of using copper wire as a heat sink considering I have lots leftover from a home improvement project.

I picked up 100 5 volts regulators on ebay for I believe it was 10 bucks, I only needed a couple at the time. I would like the newer switching regulators but I am a strong believer in using what one has on-hand.

100 regulators? Should be enough for at least a couple of weeks

Originally Posted by frank48

Anyone looking for a gps module I can recommend this one -

http://www.ebay.co.uk/itm/Micro-GPS-...item27c5216357

Super fast shipping, good price and the seller also does one with a breakout board

/Frank

Looks pretty much like the same module from flytron - if so, I have been very satisfied with the performance.

Originally Posted by Dennis Frie

Looks interesting. Have you tested how narrow the beam-width is? But if you are just looking for a couple of hundred meters range, it shouldn't be necessary with directional antennas at all

I had three of these dish antennas and trashed the single LNB unit, now I wish I had kept that one. With the Oval ones, I just learned this morning, they do not receive the signal straight on as we perceive but from the side about 20 degree. I am processing the video now and the quality is Fantastic.

I've been away from FPV for a while, but now I have taken it up again and I'm amazed to see how this project has progressed, very nice work Dennis!

That said, I'm having some trouble getting the EM-411 GPS to work with the latest code release (0.18). The OSD gets stuck at the initial screen searching for satellites even though the GPS seems to have a lock (led blinking). OSD shows zero satellites found all the time. I'm going to have a closer look at the code tonight, but I thought I ask anyway if you have any good hints of were to start looking.

Here is dump of the first few NMEA-strings the EM-411 sends after power-up if it helps:

$PSRFTXT,Version:GSW3.5.0_3.5.00.00-SDK-3EP2.01 *46
$PSRFTXT,Version2:F-GPS-03-1005051*2D
$PSRFTXT,WAAS Disable*13
$PSRFTXT,TOW: 383162*18
$PSRFTXT,WK: 1681*6B
$PSRFTXT,POS: 3114791 892802 5475428*19
$PSRFTXT,CLK: 95295*2F
$PSRFTXT,CHNL: 12*73
$PSRFTXT,Baud rate: 4800*65
$GPGGA,103203.533,5933.1519,N,01559.6400,E,1,05,5. 5,85.7,M,28.2,M,,0000*67
$GPGSA,A,3,02,13,10,30,23,,,,,,,,8.7,5.5,6.7*3F
$GPRMC,103203.533,A,5933.1519,N,01559.6400,E,0.00, ,290312,,,A*77
$GPGGA,103203.825,5933.1568,N,01559.6783,E,1,05,5. 5,49.5,M,28.2,M,,0000*61
$GPGSA,A,3,02,13,23,30,10,,,,,,,,8.7,5.5,6.7*3F
$GPRMC,103203.825,A,5933.1568,N,01559.6783,E,0.38, 260.77,290312,,,A*62
$GPGGA,103204.000,5933.1408,N,01559.6718,E,1,06,1. 2,15.7,M,28.2,M,,0000*67
$GPGSA,A,3,02,13,23,30,10,07,,,,,,,2.1,1.2,1.8*3F
$GPRMC,103204.000,A,5933.1408,N,01559.6718,E,0.25, 241.86,290312,,,A*6E
$GPGGA,103205.000,5933.1452,N,01559.6592,E,1,06,1. 2,29.3,M,28.2,M,,0000*62
$GPGSA,A,3,02,13,23,30,10,07,,,,,,,2.1,1.2,1.8*3F
$GPRMC,103205.000,A,5933.1452,N,01559.6592,E,0.06, 72.28,290312,,,A*57
$GPGGA,103206.000,5933.1451,N,01559.6520,E,1,06,1. 2,36.0,M,28.2,M,,0000*66
$GPGSA,A,3,02,13,23,30,10,07,,,,,,,2.1,1.2,1.8*3F
$GPGSV,3,1,12,13,72,216,37,23,68,092,37,10,50,280, 39,04,47,250,29*71

I would appreciate your input on this.

/Andreas

Originally Posted by Dennis Frie

The number above mah indicates the planes position (in degrees) in relation to your own position. In my case I think 0 degrees = north, 90 = east, 180 = south etc. I use it to stay within my antenna beam and keep the direction/angle when flying above the clouds.

Hello,

I guess this number is also the direction, to which a directional antenna should be steered to get the best signal. I wonder, if it would be possible to send this number and maybe also the angel according to the hight difference of model and pilot over the dark lines that are used for teletext? Shouldn't this just be equal to the creation of the signal for showing the text? If so, one could very simple decode the information on the ground and use it for tracking. This might be much smarter than an additional audio modem.

Cheers Nils

Hey, now it works!

This is what I did:
- Set baudrate to 9600 and tested with my flytron GPS which worked fine (as expected).
- Switched back to 4800 baud and connected the EM-411 GPS and now it works!

I know it doesn't make any sense but somehow that seems to have fixed it.

Originally Posted by andreas77

Hey, now it works!

This is what I did:
- Set baudrate to 9600 and tested with my flytron GPS which worked fine (as expected).
- Switched back to 4800 baud and connected the EM-411 GPS and now it works!

I know it doesn't make any sense but somehow that seems to have fixed it.

Great you made it work. That "fix" shouldn't make any difference, but who cares as long as you made it work
And by the way, great to see the GPS-output, makes it a lot easier to see what's going on

Originally Posted by nils1982ks

Hello,

I guess this number is also the direction, to which a directional antenna should be steered to get the best signal. I wonder, if it would be possible to send this number and maybe also the angel according to the hight difference of model and pilot over the dark lines that are used for teletext? Shouldn't this just be equal to the creation of the signal for showing the text? If so, one could very simple decode the information on the ground and use it for tracking. This might be much smarter than an additional audio modem.

Cheers Nils

As far as I know, it should be more stable to use the audio for downlink (than teletext). Teletext could be an option, but it's a bit more difficult to read on the ground, and I would like to keep it simple.

I started to write the code for downlink, but never implemented it, as I got annoyed with the audio-performance by my Lawmate video-tx. A working test-sketch for audio-telemetry can be found a couple of posts ago. You should more or less be able to use it directly, but I would recommend some check-sum etc.

Originally Posted by Dennis Frie

As far as I know, it should be more stable to use the audio for downlink (than teletext). Teletext could be an option, but it's a bit more difficult to read on the ground, and I would like to keep it simple.

I use an LM1881 and a microcontroller in a diversity setup, so not to much new stuff would be necessary.

Originally Posted by Dennis Frie

I started to write the code for downlink, but never implemented it, as I got annoyed with the audio-performance by my Lawmate video-tx. A working test-sketch for audio-telemetry can be found a couple of posts ago. You should more or less be able to use it directly, but I would recommend some check-sum etc.

I saw it and it looks very promising. With the audio-performance of my video-tx I was also not very happy, that's why I asked for teletext. Do you think there would be some timing/resource left in the existing code to implement the audio modem or should one use an independent controller? I think it would be enough to transmit the two necessary angles plus a checksum only.

Originally Posted by nils1982ks

I use an LM1881 and a microcontroller in a diversity setup, so not to much new stuff would be necessary.

I saw it and it looks very promising. With the audio-performance of my video-tx I was also not very happy, that's why I asked for teletext. Do you think there would be some timing/resource left in the existing code to implement the audio modem or should one use an independent controller? I think it would be enough to transmit the two necessary angles plus a checksum only.

The code for the audio-modem shouldn't take up much cpu-time. The general idea and code for bit-sending have been made by Melih from Flytron, but it have been more or less rewritten to allow serial-receiving (or other tasks) while sending telemetry. As I never implemented it I can't say anything for sure, but my guess is that no extra controller is needed.