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ddwaner

Low Power Tests

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I fly behind the Barboursville park in Barboursville WV USA and have wanted pictures of the field from the air so I did a low power test of my MVL11 setup. The MVL11 is for the most part a baby monitor which is camera and transmitter with matching receiver. I connected a standard VHS vcr with a Samsung SyncMaster 150MP flat computer monitor for ground viewing up to my 2 pound Simple stick outfitted with 5 in wheels on the landing gear and a E-Flite 480 Brushless motor and Jeti30 and a 2100 3 cell lithium. I used a old Kokam 1500 3 cell lithum battery for the cam and transmitter and off to the field I went.

From what I can tell the transmitter is a 10mw 2.4ghz transmitter and 380 LOR color camera. I have edited most of the dropouts from the video and have 3 flying days in 3 video's on my home Web Site, and I have higher resolution vids on my home FTP site in the form of MP4's. Here is the address for the vids.

Windows media player streaming from HTP, wmf files at 352x240 at about 325kbps

http://rcflyerscu.homeip.net:8081/WebVideo...og_4H_Camp.html

http://rcflyerscu.homeip.net:8081/WebVideo...H_Camp_Da2.html

http://rcflyerscu.homeip.net:8081/WebVideo...H_Camp_Da3.html

The FTP site vids are MP4's at 640x480 at 1000kbps and the address is

ftp://rcflyerscu.homeip.net/RCVideos

File names are Areal Photog 4H Camp*.mp4 (3 files)

There are also other stills and Panorama's of the 4H Camp Flying Field and Barboursville Park on my home web site at http://rcflyerscu.hobby-site.org

Edited by ddwaner

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New equipment is built and ready to try. The same camera that was on the MVL11 with a new transmitter. The transmitter was Very unflexable when it came to the power requirements so a board to hold the module had to be built and a way to supply voltages to both the camera which ran on 12vdc and the transmitter which ran on 3.3vdc. I found that the camera would run as low as a 2 cell lithium battery's low voltage cut off so I used a 2 cell Kokam 1500 to power the unit. It was hard to get a fixed 3.3vdc regulator so I used a LM317 and adjusted the values for 3.33 and all went well fitting the transmitter to the board and the smoke test produced picture on the monitor and NO SMOKE.

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The assembly is mounted to my Modified Simple Stick (steerable tail wheel, 5" Wheels, reinforced wing saddle, etc.) the plane is flown with a Futaba 7CHP, 138DP, Jeti 30, E-Flite 480, (Modified) Park zone 2200 LithiumP, APC 12x6E prop and CS-12's. The camera is mounted forward and pointing slightly down. The LM317 and its heat sink gets good and warm so I put it in the MAIN prop blast directly for cooling.

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Edited by ddwaner

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All setup and ready to fly. I will be recording the flight on my computer this time. The MVL11 video was recorded on my old VHS VCR (2hr mode). The computer is using a old Hauppauge WinTV capture card and I will compress to DVD level video with WinDVD Recorder from the MVL11 reciever with Windows XP Pro on a 1100XP and monitoring the video and recording on a Syncmaster 150MP. To power the ground equipment is a modified AEP 400 UPS running from my car battery.

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Edited by ddwaner

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For some reason I can't see anything else than those 2 HUGE wheels... :P

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I had a girl friend like that once...Sorta.....

I got made fun of and they said "It would NEVER fly". The grass is a little long at the field from time to time so I needed a solution for takeoffs and landings. The airplanes FULL flying weight with the new camera equipment is 1366 grams.

That's a little bird DOOO on the tire. I scared one the last flight. It just missed the fan.

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Edited by ddwaner

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The equipment went to the field and the UPS could not run the monitor and the computer from the DC supply.

The monitor would run as before so I range tested. The motor circuit was getting into the video but was not connected to the camera circuit in any way. The signal on the monitor resembled a receiver that was off tune. The receiver could not lock on the carrier with distance. There may be more than the audio sub carrier differences between the Airwave transmitter and the MVL11 receiver. Each channel may be offset by several mhz, close enough to work up close. I can't get a absolute carrier position list for the MVL11 but compatible equipment with the MVL11 suggests different frequency's than Airwave's spec list. It time to construct a compatible receiver and omnidirectional antenna.

..................................RCV...................TX

Chan.......................MVT10-WR..........Airwave

Ch-1..........................2.400................2.414

Ch-2..........................2.427................2.432......(Channel I was Using)

Ch-3..........................2.454................2.450

Ch-4..........................2.481................2.468

ChannelSeperation........27.....................18

Later NOTE:

The transmitter board power regulator and heat sink has NO excess heat directly after a flight on a 80 degF day. :D

Edited by ddwaner

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Looks like about 5 or so where I was txmitting.

(Got to many zeros there, that one post) :blink: "several" works better...

I just ordered the receiver module, lets see how long it takes to get to WV/USA from Canada. I ordered the transmitter module 6/8/2007 and it arrived 6/16/2007 from the UK.

Edited by ddwaner

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Regarding receiver, you might like to think about assembling the following kit, as I do:

Comtech receiver module:

http://www.lechner-cctv.com/artikel_einzel...32p1550vl1abd91

Preinstalled PCB:

http://www.lechner-cctv.com/artikel_einzel...32p1550vl1abd91

uC for Channel Selection:

http://www.lechner-cctv.com/artikel_einzel...32p1550vl1abd91

This altogether costs roundabout 52EUR and it enables you to select any frequency in the range 2300 - 2555 MHz in 1MHz steps and it's brilliant quality, (the Comtech module works best in the range 2400 - 2483 MHz).

However, it needs 12V power supply as the Comtech based receivers do. So you will need a 3s Lipo to power it. Airwave on the other hand is satisfied with 5V, you're just stuck with the preselected channels.

Cheers,

Hartwig

Edited by Hartwig

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Right now I just need to tune into the channels that the transmitter can use (including the 2 audio subs)(I am counting on Airwave working with Airwave). After I get this rig working, I'm gonna look for good diversity receiver Idea's. I have the Airwave receiver ordered and have about $44 in the tuner. I may have another $10 in the other parts (all are Shack stock) and it should work with voltages from 6.5vdc to 37vdc. The price may be better than your suggestion ($70 plus shipping) and again I am counting on Airwave working with Airwave. I plan to use the audio subs and for the first part of the project I want to use one for Horizon and the other for Altitude, probably using a 555's. [Thou shalt NOT clutter my vid feed, KEEP IT CLEAN!]

Hey thanks for the info but my German is a little weak (I only learned enough to program the RSK in Reflex).

Edited by ddwaner

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:-) It is just an idea.

BTW, I tested Airwave TX612 along with Airwave RX623 and it's great! I had some trouble with the audio which is still not resolved totally, but it seems to be related to the OSD I'm currently using.

However, I compared the video signals which go into the TX with those that leave the RX on my scope and the combination of AW612 and AW623 is quite good. Of course you see the bandwidth limitation on high frequencies (lowpass effect starting at ~3MHz), but the picture looks quite nice.

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The 634 is what I have on the way. Airwave published the exact channels that it used and they match my (Airwave) transmitter. I plan to make a antenna, that will save some money. I'm not sure if I'm gonna connect it directly or use PL259/BNC/RCA Phono or something, probably direct. I've been checking how the duckies are made for 2.4.

The 3 mhz point may be why some of the vendors label those receivers as VHS quality, another 1.5 headroom before rolloff may help that problem, that would take it to SVHS quality. The spec's for the 634 show 50HZ-5.5MHZ, that may help some later when I step the cam up to 500 LOR............ or more.

P.S.

Change your OSD character color from White to Yellow or Green (stay off the high end).

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Edited by ddwaner

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The 634 arrived today 6/25/2007 so I made a trip to the Shack for parts. The parts are on the board and the smoke test once again produced NO SMOKE and picture on the monitor. Now is the HARD PART, getting it into the box.

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Back side... I don't know how well it works yet as far as range but the picture is better than the other receiver. I was a little surprised to find that assembly produced a "OK" picture using a 4.8 VDC flight pack. The internal regulator's output was about 3.6vdc and the reciever was producing picture. I will be running the rig on 6vdc to 8vdc (2 cell lithium). The internal regulator gets a little hotter than I like on a 3 cell lithium, especially at loss of carrier (regulator max temp is 150C).

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Edited by ddwaner

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Ready for flight tests.

I changed the female plug to a cable with male ends to connect directly to a monitor or VCR (DVD Recorder). The opening allows for regulator cooling and channel selections and I added a protective antenna tube. The box measures 51mm X 28mm X 76mm :P

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Edited by ddwaner

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If you can get hold of one of those small diecast aluminium boxes, you can bolt the regulator to the inside of the box and the whole box will act as a heat sink so you won't need large openings. It should look a bit nicer and be more water resistant as well.

You mentioned a voltage drop of about 1.2V so I'm guessing you're using an LM7805 regulator. You may want to consider an LDO such as the LM2940-5.0 which has the same pinout and amp rating but has a much lower voltage drop. That will allow you to run for a longer time on the same batteries.

Be sure to post your results from your testing here! Nice work.

Daniel

Edited by Daniel Wee

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I'm short on money is why I am building rather than buying a MULTI HUNDRED dollar rig. The box was from my stock, I checked a ...Al U Mini U M... box and they wanted about $5 and I was just too cheap for that. I may add TAPE for water proofing. I will be doing recording again after I make the range checks with just the receiver and monitor. I still may have motor noise to get rid of and I'm still working on a good artificial horizon setup and maybe a altitude reading. I'm still scaveng'N for 555's and a pressure sensor. The pressure sensor is the hard thing to find. I want a strange range with a 0-5vdc output. That's still work in progress.

YES 7805

That will allow you to run for a longer time on the same batteries.
I plan to run a older 9" Sony 110vAC monitor and a transformer for the transmitter from a APC 400 UPS running from my Car Battery (I'll add a VCR later). Right now I'm trying to get what I can local (The Shack) etc. My camera plane is NOT ready quite yet so I have a little time before I step up the equipment resolution. Edited by ddwaner

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What kind of artificial horizon sensor are you using? IR thermopile?

I'm also having an artificial horizon project going - using a 5DOF IMU (basically 2-gyros and 3-axis accelerometers). If you're using gyros too, maybe we can discuss.

Daniel

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I am Cheap, Cheap, Cheap....

How about a pot with a weight on it connected to 555 and transmitted to the ground on a audio channel (my transmitter has 2). Reamp to 5vdc and move a horizon indicator with a servo mounted on my monitor. I want to sit on my but and fly from the monitor. Most important part of this experiment is a good chair.

Edited by ddwaner

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That's not going to work well for you. If you're looking for a true attitude sensor, you'll have to be thinking along the lines of a gyro. The weight you're using will be influenced by lateral forces which will corrupt your readings. But do give it a try - I'm interested to see how useful that is. I've done the same thing with accelerometers on a heli so I know that for more precise attitude sensing, gyros are required. You're right about the cost though, this gets expensive real fast, even when rolling your own.

Daniel

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To make the altitude sensor part I need a dp cell with a odd range. That will give the resolution for accuracy. I don't need to read 0 to 30,000 feet.

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Indeed the ball would give you... the ball indicator in a plane. Using it as an horizon will show you being flat in a correct turn.

I don't think you'll find a pressure sensor that will give you 0-5V for the altitude range you want right of the box. You'll most likely have to make an amplifier circuitry that will give you the range you want.

You'll need some calculation to be done somewhere too, pressure vs altitude isn't linear.

Edited by Kilrah

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Below 36,000 ft:

P = 101.29 * ((T + 273.1) / 288.05)^5.256

T = 15.04 - (0.00649 * h)

Where P = pressure in kPa, T is temp in C, and h is alt in m.

Therefore,

h = -(44383.67 * (p/101.29)^0.19) - 44403.70

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