Robert M's Posts (4)

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FPV Ground station integrating Brix

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Hardware:

Computer: Gigabyte Brix i5 4200
Primary video: ReadyMadeRC 11" monitor
Secondary video: Fatshark Dominator goggles
DVR: Lawmate 500EVO
Receivers: Lawmate 1.3 gHz (one tuned, one not)
Diversity: Eagletree EagleEyes

Case: Pelican 1450
Tripod: Dolica proline 64"
Tripod base: Manfroto

Having flown FPV for about three years now I got a bit tired of bringing a netbook with me just for programming and telemetry when I go out to the Italian countryside to fly in the weekend. While light, my netbook was not powerful enough for basic video editing, the battery ran out too quickly, it required an adapter, and was frankly was just another thing to carry around. So to make my life a bit easier I collected various parts and built my very own groundstation into in a Pelican 1450 case and it's been all smiles since then!

The picture above is from a couple of months ago in the Sibilini mountains here in Italy. It was a lovely place to fly, given the views and the wide-open spaces.

Adding a Brix to the box

What may be a bit different from other ground stations I have seen is that I have integrated a Gigabyte Brix (i5 4200) into the case to have just a bit more power at my disposal. I use a ReadyMadeRC monitor to switch between the HDMI video/audio from the Brix (for pre-flight and telemetry), and switch to the video while flying (EagleTree Eagle Eyes for diversity). I have a Lawmate DVR integrated into the top panel to be able to record everything and a Fatshark Dominator headset mostly for the enthousiastic onlookers (often local pilots) who want to check out how emersive FPV can be!

Power conisderations

The biggest challenge I had was getting all the components to "place nice". The setup runs off of a 6000mAh 3s LiPo, but the receivers and screen need 12V, the DVR runs on 3.7V and the Brix runs on around 18.3V. I ordered a handful of switches, a couple of step-up/down regulators from Pololu, and a hefty variable regulator for the Brix, and started soldering everything together. I have to say the setup works very well, the signal seems strong, images crisp and even with the computer running there is no EM intereference.

Running off of a LiPo is convenient but since the setup draws less than 5A, using a 12v lead starter battery is a safer alternative. The Brix uses the largest share of the amperage (3A using LXDE, a bit more using Ubuntu linux 14.04).

Software

I am running Mission Planner 2.0 for Linux and I have all the usual Windows-based utilitities in a Virtual XP environment, should I need them.    

If anyone has any questions, do let me know, and I'd be happy to provide any more details people are interested in!

PS. My immense gratitute to the crews behind the Mission Planner software and the APM and Pixhawk hardware. None of this would be possible without you guys!

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I am sure we have all been there; there must be a servo connector loose somewhere, you firmly press each one with fingers too large to press just one connector, you wondering whether the wires in each connector are well-crimped, you stare in dismay at at the spaghetti emerging from the APM. While working on my computer last week I just may have come up with a solution. Why not use flat ribbon IDE cable instead and 3x8 headers (http://www.pololu.com/catalog/product/1038) instead of 3 conductor servo wire? Here is what I did:



1) Reduce the width of the IDE cable to 24 connectors (3 conductors x 8 channels) 

2) Split the ends into groups of 3 conductors

3) Strip the plastic off

4) Split each group of 3 into individual wires

5) Tin each wire

6) Tin the 3x8 plug

7) If you want to use very thin heat shrink tubing, slide it over the wires now

8) Solder with a quick touch

9) Cover in liquid plastic / slide the heat shrink in place and heat it

10) Repeat for the other side of the wire

 

3689466940?profile=originalThat's it! Now you have connector that is much less prone to move about or come loose, there is less risk of bent pins, you can be press it in or pull it off easily without pulling on the wires, and it has the benefit of soldered connections. It may not be lighter that a traditional setup, but the flat ribbon can fit above or under batteries without any issues, takes up less space and just looks much neater than the traditional spaghetti.

If I am not mistaken, you can also reduce weight a little more by only conn
ecting 8 wires to the signal pins and connecting a single power and ground wire. If you still want to make sure each channel still has signal, power and ground, just solder a small wire across the power and ground pin rows on the back of the 3x8 connector. Would love to know if my theory holds water!

Notes:

!) The 3x8 plugs fit my ImmersionRC receivers perfectly, but not my Hitecs receivers. I am not sure it is possible to get them in different widths, by you can always use the 3x8 plugs on one and and traditional servo connectors on the other, at least this cleans up the spaghetti! 

!) Make sure the wires line up correctly

Happy soldering!

Robert

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Spying on Europe’s farms with satellites and drones

Working for one of the UN Agriculture agencies in Rome, I thought this was worth sharing!

Source:

Bales of hay in Wiltshire, UK - file pic

Farmers who claim more EU subsidies than they should, or who break Common Agricultural Policy rules, are now more likely to be caught out by a camera in the sky than an inspector calling with a clipboard. How do they feel about being watched from above?

Imagine a perfect walk in the country, a few years from now - tranquillity, clean air, birdsong in the trees and hedgerows, growing crops swaying in the breeze.

Suddenly a model plane swoops overhead.

But there is no-one around manipulating radio controls. This is not a toy, but a drone on a photographic mission.

Meanwhile, hundreds of kilometres up in space, the same patch of land is being photographed by a satellite, which clearly pinpoints individual trees and animals.

What is there to spy on here? No secret military installations, just farmland.

Farmer and environmental researcher

But Europe's farms cost taxpayers billions of euros in subsidies each year, and EU agricultural inspectors are turning to technology to improve their patchy record on preventing fraud and waste.

Satellites have already been in use for several years, and drones are currently undergoing trials.

Scanning a farm with a satellite costs about one third as much as sending an inspector on a field visit - £115 ($180; 150 euros) rather than £310 ($490; 400 euros), says the UK's Rural Payments Agency (RPA), which is responsible for disbursing the subsidies in the UK and checking for irregularities.

"The RPA follows up only on those claims where there is some doubt about accuracy, and then only at the specific fields for which the doubt exists," the RPA says. "This saves time, lifts the burden on farmers and reduces cost to the taxpayer."

Satellites can rapidly cover a huge area in detail and quickly return to photograph it again if necessary.

In 2010, about 70% of the total required controls on farm payments in the EU were done by satellites, which photographed more than 210,000 sq km (81,000 sq miles) of land in all.

But they are not infallible. Austria does not use them, on the grounds that the shadows cast by very mountainous terrain sometimes make satellite images inaccurate.

And Scotland, unlike the rest of the UK, decided against satellites "because of the difficulty of getting enough clear weather for flyovers", a Scottish government spokeswoman told the BBC.

Many things in the countryside are constantly changing and when the satellite passes over, "the animals may be in a field or in a barn - you can't count the numbers very well", says Roland Randall, an English farmer and environmental researcher in Cambridgeshire.

"When planners looked at the aerial photo records of our farm they thought we had an additional building without permission, but it was actually a haystack," he told the BBC.

The satellite checks are done partly to produce accurate maps of farms, showing clearly the areas eligible for subsidies.

But farmers these days have to keep their land in "good agricultural and environmental condition" to qualify for subsidies, so images also reveal whether the farmer is complying with the rules on hedges and ponds, say, or buffer strips around arable fields.

Spotting erosion from satellite imagesThe monitoring is not always to spot infringements or illegal activities. Satellite images can help identify problems such as erosion. Farmers can then be asked to change their methods to prevent further damage. In the above images, overproduction and deep ploughing in clay earth meant rain washed soil away.

A farmer who breaks the rules risks losing 3% of his or her direct payment - and more if it is a repeat infringement.

There have been few prosecutions in the UK based on satellite evidence, says Ray Purdy, a senior law researcher at University College London (UCL) specialising in satellite monitoring.

One case in the UK was dropped in 2001 because a farmer proved that he had planted a linseed crop, even though the satellite image appeared to show bare earth. The sparse young plants had failed to show up against the bright reflection off chalk downland.

This could be the kind of situation where a drone - an Unmanned Aerial Vehicle (UAV) - would come in useful.

Drones are best known for their role as remote-control killers in Afghanistan, but supporters see a role for smaller and much simpler drones in agricultural monitoring. They can get up close and take sharp photographs - and unlike satellites, which always look directly down, drones can get an angled view of their subject.

They are currently being tried out in vineyards in the south of France, to check that "grubbing up" of vines is done legally and ecologically.

Wine-growers get as much as 10,000 euros ($13,000; £8,300) per hectare in subsidies for digging up uncompetitive vines - a scheme to prevent new EU "wine lakes" caused by overproduction.

"There has to be 100% control, as it's a huge amount of money," says Philippe Loudjani, an agronomist at the Joint Research Centre, the European Commission's main satellite monitoring hub in Ispra, northern Italy.

"The French are testing to see if the drones need to go up to 10cm resolution - to see what accuracy is required."

Graphic showing use of Atmos 6 UAV (drone)

Drones are also being tested in Italy, and are already in use on a small scale in Spain's Catalonia region, where authorities say their 25cm and 12.5cm resolution photos are ideal for inspecting the small landholdings with mixed crops that are typical of the Mediterranean.

The EU is hurrying to develop a "strategy for Unmanned Aircraft Systems", which would see the existing very tough restrictions on the use of civilian drones in Europe relaxed.

A discussion paper prepared for a European Commission workshop in Brussels this week, envisages their use not only in crop or farm monitoring, but also terrain cartography, goods transport, monitoring of borders, the fight against illegal immigration and drug trafficking, and intervention in natural or industrial disasters.

Warwickshire farmer

"They can also be sent to deliver rescue packages to ship crews in danger at sea," it adds.

However, in the short term it's likely that UAVs will only be widely approved for use within line of sight of an operator and at a distance of no more than 500m, which limits their value for agricultural inspection.

And what about the privacy issue?

Ben Hayes of the campaign group Statewatch worries that Europe is rushing into the use of drones without sufficient public discussion.

"We would accept the argument that there are lots of things they can be useful for, but ... the questions about what is acceptable and how people feel about drones hovering over their farmland or their demonstration - these debates are not taking place," he says.

Ray Purdy of UCL surveyed 202 farmers in the UK, and 428 in Australia - where satellites are routinely used to monitor land use, especially vegetation clearance - and found that only about a quarter in Australia and a third in the UK were against satellite monitoring.

Some farmers voiced concerns about invasion of privacy, but many said remote sensing was preferable to inspectors on their land taking up their time.

A majority in the UK also agreed that the satellites would help to deter fraud.

Rob Allan, a farmer in Warwickshire, said "it's modern life really - I don't think there's anything you can do about it".

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ArduCularis ready for take-off

3689428345?profile=originalAfter hours of painstaking work, weeks of researching and flying in airplane parts, and more money spent than I care to think about, I finally powered up my ArduCularis for a ground test today. The LEDs lit up, the ESC sang and the servos sprang to attention. A control surfaces test came out perfectly, flaps down, ailerons and rudder. The throttle and props pushed back enough air to send a stack of my papers to the other end of the room while my FPV setup was beaming back a crisp picture of a tall man busily scurrying about his apartment, pushing buttons and pulling levers.
Alright, enough narrative, let's talk mission and setup!
In the air

Plane: Multiplex Cularis (heavily modded)
AP: ArduapilotMega (GPS, magnetometer, airspeed indicator, Xbee, current sensor)

Motor: Hacker 30A12L
Props: Graupner CAM 12/6 and 10/6
ESC: Castle Creations Phoenix ICE 50
Battery: 4000 mAh Nano-Tech
Rx: Hitec Optima 9
Telemetry: Xbee 900
Camera: Sony WDR600
VTx: Lawmate 1.2-1.3 gHz
VTx Battery: 850 mAh
Servos: Hitec 2x 4x
Weight: 1.9 Kgs / 4.2 lbs. (serious cable shortening left to do)
On the ground
Tx: Hitec Aurora 9
Netbook: HP Mini 311 running Win7home
Video-USB dongle: Yet to come in
Telemetry: Xbee 900 with high-gain ducky antenna
VRx: Lawmate
Tracking station: tdb
Antennas: tdb
Tripod: tbd
Mods:
- Rx in a slot cut into the Elapor at the back of the cockpit. (Frees up space for battery, shortens cables)
- 2x Rx BODA antennas have channels cut from the back of the Rx slot to the wing slots where they come out at the bottom of the wings
- Extra space for APM aft of ESC in the cockpit (packing foam on sides and bottom against vibration)
- Vtx ducky cut into the tail to reduce drag and balance the plane
- Low-pass filter and xtv into the fuse (stock heatsink still in the air, I may go for a larger one to dissipate better).
- Single pitot tube in right wing (sensor as well)
- GPS in enlarged switch bay on right hand side of the cockpit (I was worried about reception, but it works like a charm)
- Transparent canopy
- (ignore the wires on the wing, it's the very unfortunate result of what happens when Cularis wing holding mechanism and the servo connectors don't like each-other).
Maiden flight for GE: 2011-10-15%2005-39%201.kmz
 
I'll be using this blog to share progress, lessons learned (foam lost) and ideas as well as to hopefully illicit some suggestions on how to improve the setup further, so please feel free to chime in.
Before signing off let me just pay my respects to: Chris for his fantastic work and willingness to help, everyone who has helped develop the APM, Trappy for putting cameras on RC aircraft, and RC aircraft in places they really shouldn't go, Pedro for getting me into this hobby in the first place, and Laura for putting up with the fact that our home looks like a factory floor ;-)
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