Taranis XD9 Plus on a Walkera Runner..It Flies!!!

Woo hoo!!!  She flew like a charm just as I had hoped.  The previous two blogs walked through how I was able to integrate the Taranis XD9 Plus with the Walkera Runner 250s.  People ask me all the time, “Why should I upgrade my Walkera Runner 250 code to MultiWii 2.4.  These last posts is the perfect reason why they should.  Not because they are tired of seeing their Runners turn into Lawn Darts and be destroyed.  Not because they want to run more than one battery through the Runner before they have to pick up the pieces and go home to order $150 in parts on Amazon.  The reason is because the MultiWii 2.4 is bringing Open Source back to the Runners.  Open source is the way MultiWii was intended to be and as such, you are able to run any flight controller you want to run with the Runners.  Screen Shot 2016-08-16 at 4.33.21 PMSBUS has a significantly lower latency giving you a better repose to the quadcopter, but more importantly it gives you the convenience of taking only one flight controller to the field and multiple quadcopters. Also, I sure like being able to have the full set of features of MultiWii available to me instead of having to make sacrifices because I did not have enough channels for the switches.

 

 

Screen Shot 2016-08-16 at 4.54.17 PMOverall, it is just so nice to be able to have choices.  I have posted a video on my YouTube channel.  Hope you have as much fun with it as I did.

 

Taranis XD9 Plus on a Walkera Runner…Step 2

Remember, this will ONLY work on the Runners if you have updated your firmware with the MultiWii 2.4 firmware upgrade.  This is NOT a Walkera supported capability or firmware image.

I have selected the Taranis X4RSB receiver for this project because of it’s small form factor and mostly because it has the SBUS capability.

http://www.frsky-rc.com/index.php

http://www.frsky-rc.com/product/pro.php?pro_id=135

 

FrSky-X4RSBThe challenge with the Futaba SBUS protocol and our flight controllers is that they have inverted the signals.  For the non-technical, that means that when the voltage should be high, the flight controller is being sent a low signal.  When it should be low, the flight controller is being sent a high signal.  So in order for us to get proper communications between the Taranis receiver and the Runner flight controller and this will be common with pretty much every receiver that support SBUS and even with other manufacturers of receivers that support SBUS.  There are two ways to achieve this capability and that is making a slight modification to the X4R receiver or inserting a signal inverter between the receiver and the flight controller.

First option is to modify the X4RSB receiver.  This is pretty straight forward.  If remove the X4RSB out of the paper jacket, you will see empty pin holes on the edge of the board as shown in the diagram.  Simply solder a jumper wire that you can connect a Servo connector to that will be your SBUS signal that you can connect direct to your Runner flight controller signal pin.  You will still need to connect Power and Ground to the receiver to power up the X4RSB.

Taranis x4r Mode

 

 

The second option is to insert a SBUS inverter between the flight controller and the Taranis X4R.  This will be the easiest way for most to get proper communications going but these little devices seem to be hard to purchase.

 

 

sbus inverterI ordered one and it appears to be on the slowest boat from Singapore so I ended up testing with the modification above and making my own inverter with the schematic diagram.  It is just a few simple parts and some soldering to make it work.  I will be honest with you, I fought with this for a while until I found out that I had my transistor orientation backwards.  I guess it had been a few years since I had played with this level of electronics.  Basically, if it is not working for you then check that orientation because it worked like a charm once I had double checked my transistor orientation.  For the transistor, pretty much any bipolar NPN transistor will work.  I used the NTE 287 because that is what the local electronics store had but I am sure the trusty old 2n2222 would work perfectly.

 

SBus Inverter Schematic

 

All that is left to make this Tranis XD9 Plus and X4RSB work on the Walkera Runner is to go into our MultiWii 2.4 code Config.h file and enable the SBUS. Simply search for the SBUS section and copy and paste the dsm2 orangex so that you can create a Walkera line.  You will want to add the “//” comment line after AUX4 as we don’t want the additional processing time for channels that you don’t need.  If you want to run more than the 8 channels, since SBUS carries 16, then you will need to use WIN GUI to get access to those extra channels.  Once you have your SBUS line entered, simply test compile, and then push the new firmware down on the controller.

 

config.h sbus

 

I still need to do a flight test, but it definitely was working on the bench!

 

Taranis XD9 Plus on a Walkera Runner…Step 1

I have been playing with Walkera Runners for some time and have even wrote two books that are up on Amazon.  My curiosity got the best of me so I started building a new quadcopter that was based on the SPI F3 controller, Lumenier PDB, and the Taranis XD9 Plus w/ X4R receiver.  I had chosen the X4R because of it’s size and because it had SBUS.  Was I ever happy that I did because I was surprised at the control responsiveness that the combination gave me.

This got me to thinking, why not wire up one of my Walkera Runner 250s to the Taranis XD9 Plus radio and X4R receiver?  Everbody knows this is not possible running the factory Walkera firmware, but I have already put MultiWii 2.4 on all of my Walkera Flight Controllers. Now it was just a matter of working out which UART RX pin to solder to connect to the SBUS signal lead from the X4R and pick up +5V and Ground to power up the X4R receiver.   The diagram shows where the RXD3 Pin is on the AT2560.

at2560 pin outOnce I located the UART pin I wanted to use, it was time to get the soldering iron warmed up.  I had decided to minimize my risk of a major screw up by only soldering to one pin on the AT2560 and not pull VCC or GND off the controller.  I had decided also to run it to the top side of the controller where there was more space in the case for the additional wires.  You can see in the diagram, that I ran the wire through the ISCP pin holes to get to top side of the board.

 

top 2560 _2

I had selected “Wire Wrapping” wire to use for this because of how thin the wire is and so it should be good for the three connections.  You can see on the back side, I decided to pick up power and ground off the GPS connector to minimize the risk and also this way I have my three wires running to a nice and clean Servo Connector header.

 

bottom 2560 1bottom 2560 2

Three simple connections and this controller is wired for SBUS!

IMG_4630

Next post I will show how I modified the MultiWii 2.4 config.h file to enable the SBUS in the firmware.  My new X4R will be arriving in a few days and then I will post a video on the test flight.

This is just one reason why I ported MultiWii to the Runners.  Open Source opens up all kinds of possibilities!

 

iPhone (or Samsung) and the Walkera Runner 250

I have written two books on the Walkera Runner 250s, the Walkera Devo 7 Configuration Guide and the MultiWii 2.4 for the Walkera Runner 250.  I wrote those books out of frustration, first on the Devo 7 Transmitter as it is incredibly hard to understand the Users Guide.  While the manual is written in English, it is clearly a translated English and sometimes the translation does not come across as it should.  I know see how other countries are challenged when they have to read English translations.  I wrote the MultiWii 2.4 for the Walkera Runner 250 because the factory firmware was so bad it basically made the Runner 250s into lawn darts and very expensive ones at that.

Screen Shot 2016-05-26 at 7.06.24 AM

 

I am starting to see people use the MultiWii 2.4 for the Walkera Runner 250 and upgrade their quadcopters to the latest firmware.  One person, Mikerman50 on YouTube, in particular has posted a cool video of him connecting his Runner 250 up to a the HM-10 Bluetooth Module and is now able to have complete control over his quadcopter with a MultiWii GUI on his Samsung S4.  I did some testing as well with an application that I installed on my iPhone so you can get MultiWii GUI applications on the smart phone of your choice.

MultiWii 2.4 as what is called the MultiWii Serial Protocol and you can actually program GPS Waypoints into the quadcopter for an automated flight.  You can also have several PID profile settings so that you can tune your quadcopter for a racing or a more gentle flight for aerial photography.

I am looking forward to more adoption and more experimentation by the readers.

 

 

PIDs Made Easy….

We have been playing with the Arduino environments and Quadcopters, especially the Walkera Runner 250s.  Before my Small Business Servers were blown up by the Aabaco Team, I had several blog postings on these quadcopters so I apologize if this is a repeat for you.  The subject of PIDs for these devices (and industrial controls) can be very confusing for so many that I had decided to create a simple video that makes it super easy to understand.  For example, most people’s eyes glaze over as soon as you say the words, Proportional, Integral, and Derivative.  If you are trying to explain these control loops for the quadcopters, you have lost them before you even try to speak the fourth word.  The designers of MultiWii, Cleanflight, Baseflight and other flight control systems have spent untold hours on creating super easy GUIs to configure these parameters but without the user/operator understanding what they are configuring the end result is not favorable.  In the simple tutorial, I use driving a car as an analogy and put these “complex” terms into a context that is easy for anyone to understand.  Feedback is appreciated.