How to "hack" a cheap 4 Channel MT-600 Transmitter into a 6 Channel

I decided to write a short tutorial on how to add 2 extra channels to my MT-600 transmitter, it's relatively easy, but basic soldering skills are required (being able to hold a soldering iron ;) )

What you need:

• Any cheap Soldering Iron
• Some Solder
• 5 pieces of wire (approx. 10 - 15cm)
• a two position switch
• a three position switch
• Skrewdriver

This is how you do it:

• unscrew all 6 Philips head screws (4 big and 2 small ones)

• At the back of the main PCB you will see 5 soldering pins in total (two at the top and three on the bottom)

• simply solder the two pins at the top in the right direction and the three bottom pins to the left. It should look like this:



• The three wires should now be soldered to the three connections on your three-way switch. As you can see in my picture the switch surprisingly fitted right into the drilled holes of the upper left PCB

• The two wires can now be soldered onto the two-way switch

• To close the hatch just screw it back together, don't forget the tiny ones at the top

There you go, that's how easy it is to convert a 4 to a 6 channel Receiver (at least this type).

As you can see I did some further modification by soldering two wires to the power pins on the main PCB. I don't like these Nimh Batteries very much so I wanted some extra power connectors coming out of the case to be connected to a lipo cell. You can see the result in the picture (sry for the bad quality)

There also seem to be a three trainer connections, but I wasn't able to figure out how they work. Would've been useless anyway because I don't own a second Transmitter :P

Build-Log of the Hobbyking X666 Frame Quadcopter

The Frame:

The assembly of all components was pretty straight forward (only one spring was bent so one of the landing legs vibrated very hard while the motors were running, solution was to just cut a couple windings off).
There is no manual to the X666 Frame, but it's building is similar to the X525 so just look at Hobbyking's files page to the X525 or use this link! It's really simple to build!



Mounting Motors:

Here are the three things you need to do:

1. As I was trying to put the screws and locknuts at the right position and fasten it while the landing gear is mounted I gave up very quickly... It's just not possible, you have to remove the holding screws and these stupid easy bending springs 4 times...
2. Of course the motor cannot just be mounted as is, you first need to remove the base from the brushless motor. This is done by a small setscrew that has some strange sort of head. The inbus (or Allen) bits where either to big to fit or to small so it spin the screw. The great solution was to hold the bit angular to the screw axis. This way I was able to remove these damn screws.
3. These screws tend to vibrate themselves out so the motor will just fall out of its base. Here's the thing I learned that is essential to safely build a quad:

Threadlocker such as Loctite 243 or else

I didn't bought the ultra strong Loctite because to remove the screws you need to apply heat.

Applying this is very simple, better take too much than to little. Too much won't hurt your quad, too little may result in a bad crash.


All the other stuff:

For my first Setup I needed to upload the latest OpenSource Firmware to the Control Board. This is actually a pretty easy Task. You only need an USB-ISP Interpreter (cheap ones from EBay work just fine) or an Arduino which can programmed to act like one! I already had an Atmel AVrisp mkII from former microcontroller projects so I just used this one.
You then just need to insert the ISP Header on to the Board! Now here the fun begins...
I did search for nearly an hour to find out where Pin1 is situated so I wouldn't connect the interpreter wrong and maybe even cause damage to it... At the end I just looked very closely to the board Layout, then looked on the ATmegaP328 Datasheet which pin is Miso and Mosi so I finally could figure out that pin one is up right if you look at the board full front (so you can read the infos on it)!
For the actual programming I just followed the great tutorial given by Flitetest, which is one of the nicest RC Channels on youtube!!! link

Next thing was to solder all the 3.5 gold connectors to the motor cable and fix it with the Controller Board with Velcro. I saw someone on youtube suggesting to left the Controller Board within its foambox to prevent vibrations causing problems to the Gyros so I taped Velcro directly onto the foambox.

Last thing was to mount the colet type Spinners including props onto the Brushless motor shafts.

That was it! Actually pretty easy if you have all the necessary parts ^^
I only had to wire all the inputs of my receiver to the inputs of the Controller Board and voilà :)
Here's a pic of the version 1.0 of my quadcopter :

Now its time to wait for better weather (at least no rain) and then try it out :D





Preparation of the Hobbyking X666 frame quadcopter build

So let's start with the

Transmitter:

I bought all quadcopter stuff at hobbyking.com from the EU-Warehouse. I already had a cheap 4 Channel Transmitter with 6 channel receiver 2.4ghz from Conrad. Transmitter Link

*offtopic_on:
The funny thing with this transmitter is that you can "hack" it and add two extra channels (by adding a two and a three way switch, soldering them to obviously predetermined spots). Maybe I will add a Tutorial on how to do this in a own post but its really really simple (as long as you own a soldering iron).
*offtopic_off


What I used:

• X666 Glass Fiber Quadcopter Frame 666mm
• Q Brain 4 x 20A Brushless Quadcopter ESC 2-4S 3A SBEC
• CF 2822 Brushless Outrunner 1200kv 
• 10x4.5 SF Props 2pc CW 2 pc CCW Rotation (Blue)
• Propeller Adapter (Colet Type) 3MM
• HobbyKing Multi-Rotor Control Board V3.0 (Atmega328 PA)

The total price when I ordered all this was 85,32€ excluding the 2200mah 3s lipo (14€ ebay) and of course the Transmitter (50€). So if you have nothing you would get a pretty neat, also surprisingly big and powerful quadcopter for 150,00€ which is pretty cheap.
For this price you won't get a Plug and Fly model, which was the reason I did buy all the things separately to learn things "from scratch".

So now I had all the Ingredients you need to build a quadcopter! Yeah... right...
Here is a list of


What I forgot:

• bolts and nuts to mount the motor on the mount (16pcs each). I used M2.5 countersunk Philips screws and nyloc nuts
• gold connectors male 3.5mm (12x) for the 3 wires of the brushless motors
• double sided Tape, Velcro and some foam to save the Controller Board from vibrations