mike_kelly's blog - RC Groups
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Posted by mike_kelly | Nov 17, 2017 @ 05:00 PM | 1,567 Views
Reviews:
Mini Pixhawks compared
Daya H4 680 Alien folding quadcopter
A cheap adroid tablet for APM/Pixhawk and Droidplanner 3 - Tower
Pixraptor Pixhawk clone with sensor suspension, a better pixhawk?
Pixhawk LITE, a replacement for the now obsolete APM boards?
Marek Rokowski Simple FPV Goggle Kit
Marek's 4.3" Goggle kit
Sony QX10

Discoveries:
The 3DR Solo is raised from the Dead by the Open Solo Project
Mounting a Gimbal
New Status display for Pixhawk replaces beeps and flashing lights.
InfraRed NIR Cameras and NDVI imaging for agriculture and research
Tarot weights and measures
The Ardupliot Project Developers: The people that make it possible
Linux based Flight Controllers
Evolution of an RC Enthusiast - in search of reliability - ZMR 250 Coaxial
Mini quad motor comparision RCX H1806 RCX1804 RCTimer 1806 DYS BE1806
Ultimate LRS - APM with long range control and telemetry
Tarot 680Pro Extended arms with ESC mounted in the ends
Broken Tarot Landing Legs
Tarot Quick Detach Propeller adapters TL68B35 TL68B36
Tarot TL68B33 Anti-vibration motor mounts
Troubleshooting APM flipping on new build
My Perfect Tarot Travel Case for 650 Sport 680 680PRO 690
Canon FPV Video AV cable for S100 G10 ELPH Powershot
Boscam TS321 RC302 Channel dip switch settings mystery
What's wrong with cheap props?

Projects:
FrankenSolo: Converting a 3DR Solo to UAVCAN
A new Tarot 680Pro hybrid with Daya H4 680 metal arm clamps
Blackout mini H as a training tool
My Take on a Ground Station
ZMR 250 X8 Octocopter! Coaxial Quads
Posted by mike_kelly | Nov 13, 2017 @ 01:44 PM | 1,813 Views
This build was done to demonstrate the use of CANbus with Arducopter. DJI has used CANBus to connect flight components for a long time but it is new to Arducopter. CANbus is a network for add-ons like GPS, Compass, Power Modules, ESCs and Gimbal controllers. Instead of the rats nest of cables typical of an Arducopter build, there is one cable type, one connector and all the cables are the same. CANbus can also have fully redundant cabling if desired. No hassles splicing and studying pin-outs or searching online for the right cable. The build uses OlliW UC4H Uavcan for Hobbyists and Zubax parts.

This is a completed build. In the pictures you see that there are only three (count 'em) cables going to the flight controller: Power, Canbus and RC receiver. That is it!! It shows the simplicity and increased reliability that CANbus can bring to a build.





...Continue Reading
Posted by mike_kelly | Oct 31, 2017 @ 01:56 PM | 1,758 Views
I decided to start a new blog post on my FrankenSolo build to focus on using the CANbus tools provided by Pavel with uavcan.org and owner of Zubax Robotics.

What is CANbus? You can think of it as the Internet for multirotor accessories. It comes from the automotive and aerospace industries and has one common wiring scheme, identical connectors and daisy chained devices for all your multirotor accessories. No figuring out pinouts and splicing cables together for each new device. Nice JST-GH connectors that click into place, are easy to remove and won't fall out. The GPS, Compass, Power Module, ESCs and gimbal controller etc. could all use CANbus.




As you daisy chain your devices, the last device needs a 120 ohm terminator and only one device can supply power to the CANbus, usually the flight controller. But OlliW's SLCAN can be jumpered to be a consumer or supplier of 5 volts for the bus. If you are testing just one device without a flight controller being a supplier, the SLCAN can be the supplier. But remember, only one supplier of power on the CANbus at a time!


***note don't use the above picture as an example of the detailed wires for a CANbus connector. All of my UAVCAN devices have 5v on the left side in the orientation of this picture, not on the right as shown. ***

The first task is to get to know Pavel's UAVCAN GUI. It is available for Windows, Linux and MAC. The beauty of UAVCAN is that every device can be configured and tested from one utility - Pavel's...Continue Reading
Posted by mike_kelly | Oct 13, 2017 @ 10:53 AM | 3,194 Views

IT'S ALIVE

For me the Holy Grail of DIY quads is to have some of the features that the expensive RTF multirotors have like HD Video with RC control and telemetry on the same radio. It is a pain having a RC receiver/transmitter and a telemetry transceiver and a Video transmitter. They tend to interfere with each other in the close spaces of a quad. There are commercial versions like Lightbridge for DJI. There are some expensive DIY attempts like the CUAV Hack Link which is supposed to provide HD Video and RC control but I have not seen anyone get it to work yet with RC Control.



...Continue Reading
Posted by mike_kelly | Oct 05, 2017 @ 07:45 PM | 3,212 Views

The 3DR Solo was way ahead of it's time but like many products introduced to the marketplace it was doomed by bad timing and bad management decisions. It was envisioned as a videography tool with features never before released in this class of multirotor, like CableCam. CableCam was the ability to define a complex route the quad would fly and then you could fly that route back and forth by just moving your, redefined right stick. But when the Solo was released, to much fanfare, they did not have the gimbal ready. This left an initial bad taste in the marketplace because a video quad was not much use without a stabilizing gimbal for the camera. Then the second problem was with a bad chip design in the ESC's that caused a logic level mis-match between the flight controller and the ESC's. The flight controller operating on 3.3v logic and the ESC's chip on 5v logic levels. This could cause the Solo to fall from the sky under certain circumstances. So with too many Solo's already built and a lot of money already on the line, management decided not to replace the ESC's and to use a software fix that reduced performance to solve the problem. The Solo originally shipped with a poor quality GPS which caused fly-aways or crashes when it lost lock on the satellites. With so much hanging on this product the problems eventually sunk 3DR.

The Solo was dumped by large retailers for pennies on the dollar and the Solo was doomed to be piled on the scrap pile of failed projects.

But the...Continue Reading
Posted by mike_kelly | Sep 06, 2017 @ 02:42 PM | 4,269 Views

A quad with two motors per arm is a Coaxial Quad also know as an X8 and Octa-Quad. An X8 is inherently less efficient than a flat octacopter because the bottom propeller is blanketed or covered by the top propeller. Hence building an X8 is almost entirely for increased reliability. If one motor fails you have a second motor on each arm. An X8 is also more compact than a flat Octacopter. An Octo with same propeller size as an X8 would have to be much much bigger in diameter. An X8 can carry more weight than a flat quad, of the same prop size, but at the price of efficiency. The efficiency penalty is in the order of 15% but building an X8 is a black art. There are so many variables that getting it right with your available motors and props is difficult.


The top propeller increases the speed of the air moving down. This means that if the lower motor were running at the same speed it would just be idling. Since the air it "sees" from above is already moving as fast as it can accelerate air.

So the basic theory is that the bottom motor must run faster than the top motor. We can generally do that two ways. Increase the pitch of the lower propeller and or increase the KV of the lower motor which increases it's speed. General guess is that the bottom motor should run about 10-20% faster than the top motor. The problem is that it is difficult to get motors of any particular size or propellers of a particular length that are only 10-20% different than each other. It...Continue Reading
Posted by mike_kelly | Aug 26, 2017 @ 12:00 AM | 3,200 Views
Reviews:
Mini Pixhawks compared
Daya H4 680 Alien folding quadcopter
A cheap adroid tablet for APM/Pixhawk and Droidplanner 3 - Tower
Pixraptor Pixhawk clone with sensor suspension, a better pixhawk?
Pixhawk LITE, a replacement for the now obsolete APM boards?
Marek Rokowski Simple FPV Goggle Kit
Marek's 4.3" Goggle kit
Sony QX10

Discoveries:
The 3DR Solo is raised from the Dead by the Open Solo Project
Mounting a Gimbal
New Status display for Pixhawk replaces beeps and flashing lights.
InfraRed NIR Cameras and NDVI imaging for agriculture and research
Tarot weights and measures
The Ardupliot Project Developers: The people that make it possible
Linux based Flight Controllers
Evolution of an RC Enthusiast - in search of reliability - ZMR 250 Coaxial
Mini quad motor comparision RCX H1806 RCX1804 RCTimer 1806 DYS BE1806
Ultimate LRS - APM with long range control and telemetry
Tarot 680Pro Extended arms with ESC mounted in the ends
Broken Tarot Landing Legs
Tarot Quick Detach Propeller adapters TL68B35 TL68B36
Tarot TL68B33 Anti-vibration motor mounts
Troubleshooting APM flipping on new build
My Perfect Tarot Travel Case for 650 Sport 680 680PRO 690
Canon FPV Video AV cable for S100 G10 ELPH Powershot
Boscam TS321 RC302 Channel dip switch settings mystery
What's wrong with cheap props?

Projects:
FrankenSolo: Converting a 3DR Solo to UAVCAN
A new Tarot 680Pro hybrid with Daya H4 680 metal arm clamps
Blackout mini H as a training tool
My Take on a Ground Station
ZMR 250 X8 Octocopter! Coaxial Quads
Posted by mike_kelly | Aug 19, 2017 @ 11:00 AM | 4,229 Views
In this series of articles we have gotten a Pixhawk loaded with firmware and the basic setup done. Now before we go any further we really need to talk about troubleshooting problems that will arise. The primary tools to help troubleshoot the Pixhawk are it's logs. This is because you can turn on logging for almost every aspect of the Pixhawk. Without the logs your aircraft might suddenly fall from the sky and you probably would not have a clue why. Looking at the logs can give you the clues you need to discover your problem.

Pixhawk has two different logs.

Telemetry Logs and Dataflash logs.

Telemetry Logs:

T-Logs save the communication between the aircraft and the Ground Station when you have telemetry radios installed and in use. It is a recording of all the Mavlink messages sent between Misson Planner and your aircraft during flight. The logs are stored in C:/Program Files (x86)/Mission Planner/logs.

Mission Planner creates a different directory under "logs" for each aircraft you fly. The logs are dated so you can tell which one belongs to which flight.

It can get a little confusing because there are many different kinds of logs created. But here we are just talking about the t-logs.

In Mission Planner, on the Flight button and under the Heads Up Display (HUD) are a group of tabs. One of these tabs is labeled Telemetry logs. You can select "Load Log" and play back your flight to see all the same telemetry that was being displayed during the...Continue Reading
Posted by mike_kelly | Mar 20, 2017 @ 01:51 PM | 8,302 Views
In part 1 of this article we installed Mission Planner on our desktop or laptop and used it to load the firmware for our vehicle into our Pixhawk.

The next step is to configure and calibrate your Pixhawk.



Plug the USB cable into your Pixhawk. (Note: the USB sockets on all these flight controllers are not very durable. Be careful when you plug in a USB cable. It is not uncommon to push the socket off the board and ruin your flight controller if you push too hard.)



With Mission Planner up and at the opening screen, go to the upper right and choose your com port and set the baudrate to 115,200. Then click on connect. Mission Planner will query the flight controller and make a connection. Then it will download all the settings of the Pixhawk so that you can view or change them. The information in the heads-up-display (HUD) on the upper left will not be valid until Mission Planner finishes connecting. But when it does finish you will see the HUD change as you carefully pick up your flight controller and tilt it. Note that the artificial horizon will tilt the opposite way to the way you tilt the flight controller. This is the way it should work. In the box below the HUD you will see the numeric values of the sensors changing as you move the flight controller.

...Continue Reading
Posted by mike_kelly | Mar 18, 2017 @ 02:09 PM | 9,734 Views
Ardupilot and Pixhawk, hands down, have the best features per dollar than any other flight controller. That is, if you are doing work and not racing. But with that extensive set of features comes complexity. The key is learning only what you need to get started in order to not get overwhelmed at first. Then, add new features as you need them.

Let's take a look at the system and what it entails.



First, you have your flight controller. It will be a Pixhawk or one of the derivations of the original Pixhawk designed by Lorenz Meier of the Swiss Federal Technical Institute of Technology as a graduate student project (www.pixhawk.org). This board is basically a computer chip with memory to store values and sensors to figure out where it is located and how it is moving. The flight controller computer requires software to teach it how to do its job. This program is called Arducopter, or Arduplane etc., and it is firmware that you load onto the flight controller. There are two different versions of firmware for the Pixhawk. It is a little confusing. The hardware previous to the Pixhawk was called the PX4. This board was in two pieces with the i/o on a separate board but newer versions integrated both boards into one like the Pixhawk did. When the Pixhawk, an improved version of the PX4, was released and funding support provided by 3DR the progress of features and improvements moved rapidly with the Pixhawk and the PX4 was left behind. The license for using the Pixhawk design...Continue Reading
Posted by mike_kelly | Mar 15, 2017 @ 01:20 PM | 11,055 Views

***** Note: I am a copter guy and this article is about how Arducopter is setup.
***** Arduplane , Ardurover, Ardusub etc. are similar but not exactly the same.
***** The information in this article applies to the Pixhawk, not the APM flight controller.
***** See my older article "Controlling external devices with an APM"
***** for information about the APM. Some of the parameter names have changed since
***** Arducopter 3.3.3 so they may not match what you have used previously.
************************************************** ******************************************

LED Lights, Spot Lights, Grippers, Retracts, Cameras, Gimbals
There are many external devices you may want to control remotely from your radio or automatically during a mission with Pixhawk.

The first thing to consider is what kind of signal controls your device? Does your device require a simple on-off switch to turn it on and off or activate it? Or, does it respond to a PWM signal like your RC Transmitter puts out? A PWM signal is a series of pulses that represent numbers. A device that is controlled by a PWM signal can decode the number, like your throttle does, to determine not just an on-off but a continuously changing value. PWM devices are much more complicated than simple on-off devices. You can get simple LEDs that just require a voltage to turn them on or more complicated LEDs that use a PWM signal to control colors and moving patterns, etc. The simple on-off control is called &...Continue Reading
Posted by mike_kelly | Mar 06, 2017 @ 01:08 PM | 7,880 Views
One of the most critical components of a successful build is getting the motors to spin in the right directions on the right arms and getting the right props on the right motors. Using the motor order pictures is the first step. The images show the different aircraft configurations, like quad, hex, octo etc. and they illustrate what arms should have motors that spin in what directions. These drawings are viewed looking straight down on the top of the multicopter. Remember that with a Coaxial multirotor the bottom motors are mounted upside down but the drawing shows the spin direction as looking down from the top, so the bottom motors have to be setup so they spin correctly even tho they are mounted upside down and the top side of the props must be up. Hence the props are mounted the opposite side up than the top motors so all props have top side pointing up.

IN Arducopter 3.5 and later there is a new Frame_class and Frame_type parameter that you must set. Class is a hex, quad or octo and Type is an X, H or Plus which specifies the orientation of the frame.

The difference between an X configuration and a H configuration is that the H rotates the motors around one position to help Yaw control on H frames that have a long center boom with arms that tend to twist around that center boom under heavy load. If you have quad that looks like an H but has a stiff box like center or other design which does not tend to twist under load then use the X configuration.

Here are the...Continue Reading
Posted by mike_kelly | Mar 01, 2017 @ 10:57 AM | 8,707 Views
One of the most important safety features of the Pixhawk is the Return to Launch or RTL. This feature will cause the multirotor to fly back to its home point due to a number of "triggers" or alarms that will cause the action. There are a number of fail-safe parameters in Arducopter that can be set such that if the threshold is met they will trigger a RTL event. For example, if your battery voltage drops below the level you set, if the ground station link is lost, if your transmitter link is lost, etc.

These events will trigger a RTL. The multirotor will fly back to the home point and hover or land. The key here is that RTL is a GPS- dependent mode. You must have a good quality GPS lock. One of the problems with multirotor GPS is that most only give an indication that they have or don't have a 3D lock on the satellites. But a 3D lock is just a minimum reception of the satellite signals to determine your location. Ardupilot wants you to have more than a simple GPS lock and that means 8 satellites and a good quality reception of the signals. That is why I think the new status display code being incorporated into the next versions of Ardupilot are so important. The little OLED display will tell you if you have a GPS lock, with how many satellites, and the quality of the signal. This is valuable information for an aircraft that depends so much on GPS navigation.

https://www.rcgroups.com/forums/show...s#post36621680





When the flight controller is triggered to RTL...Continue Reading
Posted by mike_kelly | Feb 22, 2017 @ 11:24 AM | 9,195 Views
A lot of people like to use retractable landing gear to get it out of view of the camera while flying, even though it does add weight to your aircraft.



In the simplest case, the landing gear is retracted using small motors turning a screw shaft. It responds to a standard PWM signal from your transmitter. You can test it with a servo tester to see what PWM value causes the change from retracted to extended. Let's say the value is 1500. You set up a switch on your transmitter to be 1100 in one position and 1700 in the other. This way the extend setting is clearly below 1500 and the retract position is solidly above 1500. Flip the switch and your landing gear (retracts) goes down, flip it the other way and it goes up.

Because the retracts have motors that pull a lot of current you can't power them from the flight controller. You need to power them with their own BEC. But different brands of retracts use different voltages, anywhere from 5v to 20v, so check what yours need.

Some retracts use a "smart" controller. The retracts will not operate directly from a PWM signal. You need to connect the controller to the PWM signal and the retracts to the controller. These smart controllers can do things like automatically extend the landing gear if the aircraft loses the transmitter signal.

To connect your transmitter switch to your retracts use the SERVOx parameter. If say your transmitter switch is on channel 7 and you connect the retracts to aux2, you would set...Continue Reading
Posted by mike_kelly | Feb 12, 2017 @ 04:37 PM | 8,528 Views
One of the biggest difficulties I found, and still find, with RC is orientation. As a clear example, when you are flying a plane away from yourself your right is the plane's right and your left is the plane's left. Pretty easy to figure out which way to move the sticks to keep the aircraft flying away from you. But as soon as you need to turn around and come back, the controls are reversed. Your left is the plane's right, etc.

It is very good practice to learn to make this adjustment and to be able to fly in manual mode for both planes and multirotors. But for people like me, who just can't think backwards, there is Ardupilot Simple mode and Super Simple mode.

What this does for you is to calculate where the aircraft is located relative to where it took off, where it was pointed when it took off, and make all flight corrections relative to that start. So the movement of the craft is always relative to you. If you want it to go left move the roll left. If you want it to move right move the right roll stick right. It no long matters which way the aircraft is pointing. If it is a small dot on the horizon and in addition has drifted around the yaw axis so it is pointing sideways, it doesn't matter. The flight controller figures out where the craft started and how it was pointed and will always make corrections relative to home. So as long as you start with your aircraft pointing away from you and always keep looking at it in the same orientation it will always move in a...Continue Reading
Posted by mike_kelly | Feb 11, 2017 @ 11:34 AM | 8,502 Views
When you fly line of sight and get far enough away that your aircraft is just a black dot in the sky it becomes impossible to know which direction it is pointed. As you fly the aircraft it can drift around the yaw axis causing you not to realize it is pointed in a different direction than what you expected. Then you apply roll or pitch and it goes in the wrong direction from what you expected. You can quickly lose control this way.

There is a feature of Arducopter to help this problem. It is called ResetToArmedYaw. What it does is return the aircraft to the orientation it was in when you took off. It is good practice, when flying line of sight (LOS), to always keep your aircraft in front of you from the time you take off. So if you point yourself in the direction you want to fly and point the aircraft, on the ground before take-off, in the same direction then the ResetToArmedYaw will always return the aircraft to that orientation so you know which way it is pointed.

***edit > just to make clear the ResetToArmedYam rotates the multirotor around to the original way it was pointing when it took off, at the current location. It does not return the aircraft to home. It simply rotates it, in place where ever it is, so it is pointing the same direction it was when it took off. ***

ResetToArmedYaw is implemented by using the Auxiliary Function Switches in Ardupilot. These are used with channels 7 or 8 (Using Arducopter 3.3.3 or later you can use ch7-14) and configured in Mission Planner‘s Config/Tuning | Extended Tuning screen:



There are a whole series of Auxiliary Functions available on this drop down menu.

More information at http://ardupilot.org/copter/docs/cha...8-options.html
Posted by mike_kelly | Feb 08, 2017 @ 02:03 PM | 8,687 Views
I don't know what you call it but it does not involve the arm clamps that break.




I have come to the conclusion that the best compromise between efficiency and long flight times is a hex. It provides some redundancy, when designed correctly, and yet is much more efficient than an octo or coaxial quad. But there are lots of things I have not liked about the Tarot 680Pro, first of which is the arms clamps. I think the 16mm arms are quite strong. It is the arm clamps that introduce flex. When you try to go larger like the Tarot960 with 25mm arms you are adding considerable weight. With every 60g representing a loss of 1 minute of flight time there is a point of diminishing returns going bigger to get longer arms and bigger props for a longer flight time.

I took the nice new aluminium arm clamps from the Daya H4 680 Quad and used them on a Tarot 680pro to eliminate the Tarot plastic arm clamps. I made a new top plate to transfer the hole pattern, for the arm clamps, from the Daya top plate. I used a piece of copper clad circuit board for the top plate so I could ground it and create a shield from the power level below the top plate. This protects the flight controller from radio freq interference and it also provides a ground plane for my GPS receiver and RC Control receiver.

...Continue Reading
Posted by mike_kelly | Jan 30, 2017 @ 12:10 PM | 7,978 Views
I am constantly surprised at how hard it is to interface things together in multirotors. An example is putting together a Gimbal where the manufacturer seems to have no interest or plan for attaching the gimbal to a multirotor. Many have no method to attach other than bolting it in place to the bottom of the multirotor. A gimbal often needs to be able to be moved back and forth to balance the camera/gimbal on the frame. Tarot has their two carbon tube rails system but most gimbals have no way to attach to it.



No holes to mount the Tarot hangers:



One of the international aspects of the hobby is the creative ways people find to solve such problems and their willingness to share what they have done. One such person is Alan from the United Kingdom who designed an adapter to adapt the DYS NEX gimbal to a Tarot two tube rail system.

...Continue Reading