Wednesday, October 22, 2014

Blackout MiniH Quad Bulid Log - 2

In the second part of the build log I am going to run through the radio gear and other bits before getting into the meat of the build.

It probably sounds pretty obvious but if you can finalize your shopping list all at once then you are going to save a lot of postage charges.


FrSky Taranis DX9
The joy of owning a real RC transmitter with a thousand buttons is that you own this big chunk of radio gear with a thousand buttons.

I went for the FrSky Taranis DX9.  As luck would have it they had just released a new model making for a well timed price drop on this particular model.

For my level of skill and intended use, I was never going to know what I was missing from the new one so took the savings and ran.

The Taranis is a 2.4 Ghz, 16 channel  radio and uses the Open TX opens source software.  It is not a turn on and go sort of radio.  You have to program everything you want it to do which fit the bill for this project.  More to learn on the go is a good thing in my books.

For that small inconvenience you get a whole lot of flexibility in how you set it up and also allowing it to work with receivers from other brands as well as just the FrSky gear.

The final bonus is that it is arguably as much if not more transmitter than a Spektrum or Futaba while being half the price or better.


FrSky D4R-II
This was momentarily the most confusing part of the purchase list.  I went for the FrSky D4R-II 4ch 2.4Ghz receiver that also includes telemetry.

The confusion was that I had to get my head around CPPM mode and how a four channel receiver actually becomes an eight channel receiver that pipes everything over one wire rather than one wire per channel.

Just to confuse things more, it seems it probably needs to be flashed with new firmware to make the eight channels work properly because of problems with the CPPM frame being too short at 18ms resulting in data loss.  The updated firmware makes the CPPM frame 27ms long so as I understand it, it has time to get all 8 channels of information over the line.

Head spinning yet?  Yeah, I'm learning a lot more than I expected too!

Needless to say I have not got around to flashing anything but have it working CPPM mode and hope that since I am not using all 8 channels at this time that I can avoid issues while I read and learn more.  If not I can blame any crashes on the receiver and me going to full throw on everything at once.

If you have 20 minutes to spare and want to go deep into the Matrix watch this:

If you want the short version, watch this:

Either video will help explain how the magic happens.  You have probably realised by now that there are a lot of very helpful people out there who just love this stuff.  The trick seems to be in working out what the question is before you go looking for an answer...

The other bits

The final piece of the puzzle is to do with leads and connectors.

One thing you need to identify is the connector on your battery packs as that will determine what you need on the quad end of things to get the power into it.

The batteries I bought use the XT60 connector so a pack of Male XT60 connectors was first on the list.

Now while the receiver comes with a nice little harness of wires and plugs, it is not really what I needed since I was going to use the CPPM to link the FC and receiver.  All I needed was a single 3 core servo wire for power, ground and signal.

I also needed a two wire connector for the buzzer, another for the telemetry and a third for sending power to the flight controller for voltage sensing in the telemetry.
Servo lead male connector

The crazy thing is, I thing is I can't seem to find what these little connectors are called and it seems even harder to find a double version as is needed in various places on the Naze32 flight controller.

The solution is to buy a pack of Male to Male servo extension leads and cut them in half to give you two connectors.

You can then remove the wire you don't want, solder them on where needed and even trim the connector down too if needed with a nice sharp knife.

More details on that soon but safe to say a 5 pack of 150 or 200mm extensions will get you out of trouble.

Some other items in your shopping list will include heatshrink of various sizes - I used 3mm for my wiring and 20mm clear for my ESCs and some liquid electrical tape, solder and a good soldering iron.

The piezo buzzer was bought at Jaycar and was a generic surface mount buzzer that will handle 3 to 15volts.  I soldered this onto one of the butchered servo leads as detailed later.

The final cool thing are Rapstraps.  You can use regular cable ties but the Rapstraps have some stretch making them a nicer way to secure things and they can be undone and re-used easily if needed.

Next post - the build...