DIY Drones at 63,000 members!

It’s customary and traditional that we celebrate the addition of every 1,000 new members here and share the traffic stats. This time it’s 63,000!!!!

There were approximately 1.7 million page views in the last month! (we now get around 57,000 page views a day on average). It took us just 24 days to add these latest 1,000 members–we’re averaging one new member every 35 minutes!

Thanks as always to all the community members who make this growth possible, and especially to the administrators and moderators who approve new members, blog posts and otherwise respond to questions and keep the website running smoothly.

Regards,

TCIII Admin

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Small Drones accelerate and improve stockpile reporting for mines and earth work supervision.

Not only are they the safest, quickest method of quickly taking a snapshot of an entire highly dynamic site, they significantly reduce surveying costs. Adding powerful structure from motion (SfM) software and virtual survey tools to the equation means no boots on the ground and no need for interrupting any operations.

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What happened at the AMA Expo?

I’ve been a card carrying member of the Academy of Model Aeronautics (AMA) for over a decade, when my first plane was a 2-channel toy with a turning radius of Texas from a hobby store. Today that humble start has grown into a whole collection of Warbirds, 3D planes, EDF jets, Helicopters and of course the Multirotors. I’ve always meant to go to the AMA Expo held every year in Ontario in South California, but for one reason or another I never quite made it. This year given the influx of “drones”, I wondered how the AMA and the AMA Expo was coping with this change. I was covering the AMA Expo for RC Flight Camera Action Magazine in the UK. So this post is going to be a bit different, as I realized that I had a lot of photographs. So instead I’m going to let the photographs do the talking, interspersed with commentary from myself. Blog post on AMA Expo

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What happened at the AMA Expo 2015?

Introduction

I’ve been a card carrying member of the Academy of Model Aeronautics (AMA) for over a decade, when my first plane was a 2-channel (Motor Off-On and a Rudder) toy with a turning radius of Texas from a hobby store. Today that humble start has grown into a whole collection of Warbirds, 3D planes, EDF jets, Helicopters and of course the Multirotors. I’ve always meant to go to the AMA Expo http://amaexpo.com/ held every year in Ontario in South California, but for one reason or another I never quite made it. This year given the influx of “drones”, I wondered how the AMA and the AMA Expo was coping with this change. Luckily I managed to get a Media Pass as I was covering the AMA Expo for RC Flight Camera Action Magazine in the UK (also thanks to AMA for sorting the pass out for me.) So this post is going to be a bit different, as I realized that I had a lot of photographs. So instead I’m going to let the photographs do the talking, interspersed with commentary from myself. Here is the blog post What Happened at the AMA Expo?

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Navio+ and Odroid-C1: the most powerful Linux autopilot

Greetings!

 

Some time ago we’ve released a new version of our Linux autopilot – Navio+. Main new feature is that Navio+ supports HAT standard and is compatible with Raspberry Pi models A+,B+ and also with… Odroid-C1. It is a new board from Hardkernel powered by quadcore 1.5GHz CPU with 1GB of RAM. Odroid-C1 sets a new standard for performance – it is fast, 10 times faster than Raspberry Pi and faster than most of the single-board computers on the market. It also features EMMC storage for high performance memory operations. Another benefit of Odroid C1 is that you can build APM on it in just 45 seconds.  

 

Here are the benchmark results for Raspberry Pi B+ and Odroid-C1 made by intorobotics.com:

 

201411171955007939.jpg

 

The full comparison article is here.

Besides DMIPS, very important improved metrics are system call overhead and context switching that will positively affect real-time capabilities.

We’ve added support for Navio+ and Odroid-C1 combo in APM. The porting was mostly straightforward thanks to the APM’s HAL and as we already had the drivers for Navio+. As Odroid-C1 is a new board, not all required system features were implemented and we had to do some tuning. Luckily, Hardkernel team is very responsive and great in communication and helped us solve the problems as we found them.

Most of the features are implemented for C1 such as toolchain configuration, build target, IMU, baro, GPIO driver, RGB LED etc.

But we won’t be kept without work, a couple of things are still left to do:

  1. RT_PREEMPT kernel. The real-time patch doesn’t apply as smoothly as on Raspberry Pi’s Linux, so we’ll have to deal with that by manually applying the failed hunks.

  2. RCInput. This is a tricky part on Linux, but on Raspberry Pi it was solved by using DMA. We can go that way too, but Amlogic S805 has quite a few other peripherals we can use – unlike BCM2835 it’s got a lot of spare timers that can generate 1us interrupts. Datasheet was only released a couple of days ago and we’re currently exploring the possibilities.

 

APM’s port for Odroid-C1 is available here:

https://github.com/emlid/ardupilot/commits/navio-odroid-c1

For now our main goal is to take Odroid-C1 into the air and we believe that many exciting projects will follow that will take advantage of incredible processing power.

 

Emlid team

emlid.com

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Angle of Attack Wind Vanes

 BasicAirData Air Data Boom
Triggered by some chat around the net I post here some material about mechanical wind vanes design. 
Angle of attack measurement by means of wind vanes will be first introduced. The topics to be covered in this miniseries are design, practical issues and modeling.
Angle of attack (AoA) instruments measure the angle between the airspeed vector and a predefined line on a cross-section of the airplane wing. This line is usually selected either as the zero-lift line or the chord line of the airfoil. AoA is often indicated by the Greek letter alpha. This angle is often used to calculate the lift of said wing section. AoA vanes are also called alpha vanes.
AoA usually changes across the wingspan of the aircraft and this is something one should take into account. A visual example is a wing which twists progressively across its span, flying straight and level. The AoA at the wing root differs from the AoA at the wing tip by the wing geometric twist term.
AoA measurements are are useful for parameter identification, general aviation planes or even to FPV pilots of RC-aircraft, since they can be used as an early warning indication as the vehicle approaches stall. The use case affects the choice of the AoA sensor type and desired performance. There are many types of AoA measurement devices, of which the most common are:
  • Wind vanes;
  • Null seeking devices;
  • Static-type devices, based exclusively on pressure measurement.
For a general description of these typologies, please refer to NACA-TN-4351.
In this section we will focus on a classic mass-balanced wind vane design. Even though it is less attractive than a pressure-based unit or closed-loop null seeking device. Making and calibrating a good wind vane is well-withing the reach of a DIY maker. The wind vane visible below is made by Basic Air Data members and visualizes the main components of the system. A rendering of the completed assembly of the vane can be seen in figure AoA 2.
Figure AOA.1 – Miniature DIY Wind Vane detail (JLJ and GC);
Caption – 1 Counter weight, 2 Fin, 3 Main rotation shaft, 4 Bearings,
5 Potentiometer, 6 vane body
Equally important to the instrument itself, is the definition of the quantity under measurement: an adequate design requires stating specifications beforehand. Initially, our focus will be turned towards common design aspects and then some specifications will be proposed. A lot of bibliography can be found regarding weather vanes specifically; in principle, it’s a valuable resournce but not very helpful when it comes to design requirements.
There are two main macroscopic differences between weather vane and alpha vane applications: range of speeds and the vane support structure, which is needed to isolate the instrument from vibrations degrading measurment quality. Imagine a wind vane fixed on a cantilever beam. In such configuration, which resembles a nose-mounted airboom, the whole structure may start to oscillate. As a case study, we will consider a planar oscillation (ref eq.36).
Given the height of the wind vane mounting point, h, and its airspeed, u, the error angle caused by beam deflection can be calculated as:
Given an airspeed of 20 m/s and a maximum deflection of 20 mm at 10 Hz, the error is:Another issue to be taken into account is that the motion of the mount at the
wind vane mounting point can interact with the wind vane dynamics. To avoid performance degradation it is crucial to maintain the resonant frequencies of the two systems well apart.
Since the air-boom doesn’t have a simple geometry, the calculation of the vibration modes is not feasible using a closed form formula.
A 3D model needs to be created in a computing environment and FEM modal analysis be carried out. Alternatively, lab tests are also a way to obtain such data. Figure AoA 3 depicts the first mode of the probe. Elmer is a notable open FEM package that can be freely downloaded and can handle dynamic analysis.
Generally speaking, the stiffer the airboom, the higher its first resonant frequency will be. Higher airboom resonant frequencies are desirable, since they present an uppper performance limit for the wind vane. As a rule of thumb, if the airboom assembly moves under a slight force of the hand while while fixed on the ground, some vibration-related problems are to be expected.
More accurately, if numerical analysis tools is available, make sure that the first resonant frequency of the airboom is far from the desired wind vane operational range. An offset of at least 0.3 times the first mode frequency is a good, conservative value.
Resonant frequencies of higher order can be usually neglected, as they carry significantly less deflection energy. For best performance, it is always a good idea to make sure that to other vehicle components create excitations in the low to mid frequencies of the wind vane.
Let’s proceed by examining wind vane behavior; refer to figure AoA 1.
The most critical component are the bearing. A Coulomb friction model will be used to describe their static friction.
The phenomenon of static friction, or stiction, results in the torque that is necessary to start rotating a resting bearing being greater than the torque required to keep it rolling. A graph representation of this phenomenon is found in figure AoA 4. This non-linearity leads to some problems when it is incoroporated in numerical integration algorithms.
Firstly, longer integration calculation times are to be expected. Furthermore, limit cycles and solution collisions may be generated, in other words the solution may be non-steady/cyclic or converge to a terminal value that yields a non zero static tracking error.
Analysis can become much neater if the model is writen down as a Filippov system: a nice, sliding bifurcation arises.
Figure AOA 2 – Miniature DIY Wind Vane 3D model (JLJ and GC)
 
Figure AoA 3 – Modal analysis on the probe, first mode frequency is 106Hz.
The probe is fixed at the root. The Maximum deflection at the tip 3 is 25 mm, 16 mm at the 2 windvane fixation point and 0 mm at the root 1.
 
Figure AoA 4 – Bearing friction model including stiction
Many articles are available on the wind vane topic, for example: J. Wieringa (1967), Evaluation and Design of Wind Vanes, Royal Netherlands Meteorological Institute, De Bilt (Download link)
Commonly, the vane dynamic behavior, at least near equilibrium, can be assimilated as one of a second order underdamped system. Standard industrial methods for determining the dynamic performance of a wind vane also exist, for example ASTM—D5366 “Standard Test Method for Determining the Dynamic Performance of a Wind Vane”.

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Sony shows smartwatch drone control

From Postcapes:

The combination of sensors and inputs in many smart wearable devices leads to some interesting possibilities for intuitive and immersive gesture-based user interfaces. A trio of Sony engineers (Peter Bartos, Alexander Najafi and Jonas Hellström) recently demonstrated this phenomena with their mashup project for controlling a quadcopter drone with a smartwatch and some prototype eyewear.

 IoT Mashup #003: Wearable Drone ControlIoT Mashup #003: Wearable Drone Control

Drawing on the accelerometer in the SmartWatch 2, the drone’s movement is controlled by the tilt and twist of the wearer’s wrist. The SmartEyeglass prototype displays flight data and can even show images from the drone’s camera.

 IoT Mashup #003: Wearable Drone Control

Both the watch and the glasses are paired over Bluetooth to a mobile device, which passes flight instructions to the drone over Wi-Fi.

SonyDrone_comms_650

drone-mashup1

arm-control

view

 

The engineers published open-source code and a tutorial for replicating the project.

 

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New T-motor air gear 350 & Naza light upgrade trick

Hello all,
I like to introduce propulsion system from T-motor
air gear 350  T-Motor Air Gear 350 Power Combo with 2213 920KV Motor & T9545 Propeller responsible pricing from T-Motor 
I Like to rant about something that bothering me this DJI Nazi light hack for a couple months now! This hack allows same functionality as DJI NAZA V2 from a simple boot loader hack!
Nazi light Properly the most popular flight controller out there nest to APM 2.5…
I had to find out on YouTube not my favorite blog ‘DIY drones!’. My issues is a DIY community
For free delimitation of information. I am consented that DJI is trying to down play this issue using it’s clout to sensor this information , Having posts removed from popular RC blogs all over the web!  
How to can be found here use at your own risk! 

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