Setting up a JR 9503 with an MK Okto

Bartman

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I had originally intended to use an older Futaba 9CHP for my MK Oktokopter but when a fellow builder mentioned a website (www.thebarnfloor.com the real price shows up when you place the item in the shopping cart) selling the JR 9503 new for $449.00 I decided to buy one. The Futaba would have worked but I'd have had to hack the receiver and then replace it later when I eventually upgraded to a 2.4gHz radio. This configuration works for my MK Okto with a camera and one set of LED's. If you can get through this and make it work, chances are you'll be comfortable making changes for your specific configuration.

Before you can begin to set up your radio's channel assignments it helps to become familiar with the term POTI which has to do with how you assign functions to your MK's flight control (FC) board. Other multi-rotors may use the same term but with MK it's definitely POTI. On an airplane with direct control from your receiver to the servos, how you assign the channels is how the receiver moves the flight controls. On an MK though you have MK Tool which is a software go-between used to program the flight control board so it understands what you're asking of it from the radio Tx.

In the software, MK functions are assigned POTI numbers. Since multiple functions can be made to occur simultaneously (white LED's illuminate when altitude hold is engaged), there may be certain POTI numbers assigned to more than one function. It takes a little time to figure out where to point all your POTI's but once you do you can then assign them to individual radio channels. The place to do this is under the Channels tab in MK Tool which you get to by clicking on the Settings button in the middle of the right side of MK Tool.

You need to have your flight control board functional and connected to the computer via your MKUSB or MK Tool won't let you into the main part of the software. If you are only connecting the FC board without anything else then you can use the jumper on the MKUSB to provide it with power from the computer. The jumper should be removed every time after you disconnect because if you hook up to the MKUSB with battery or bench power to your MK and the jumper in place, you can damage things.

My goal with the radio set up was to have all the switches up or forward at take-off. If the switches all had different positions then I'd have to stop and think about it before every flight. The way it is now, i push everything up and forward and I'm ready to go knowing it's configured correctly.

The first four channels will likely be the same for everyone using Mode 2 radios where the right stick is (nick) and roll and the left stick is throttle and yaw.
Gas, Channel 1
Yaw, Channel 4
Pitch/Nick, Channel 3
Roll, Channel 2

Channels are assigned via the little drop down menus next to each function or POTI. If you're looking at MK Tool as you're doing this it's easy to figure out. If you're reading it in preparation for your MK project, trust me it will make more sense once you've got things to the point where you can have MK Tool open and read this at the same time.

Under the Channels tab on the left side you'll see where the POTI assignments start just below the word ROLL. I'll just list my assignments and then explain them afterwards.
POTI 1, Channel 6
POTI 2, unused (the JR 9503 is 9 channel so to leave a POTI unused I assign it channel 12)
POTI 3, Channel 6
POTI 4, Channel 7
POTI 5, Channel 9
Channel 6 controls the GPS (free flight, position hold, come home) and the red LED's on my front arm light up solid or blink depending on what the GPS is doing.

Under the Output tab next to where it says Out2 Timing, use the drop down menu to select POTI 1. You've just assigned the Output 2 signal to POTI 1 which is assigned to Channel 6 on the radio. I'll get to radio channel configuration after we get the POTI's assigned in MK Tool.

Under the Navi-Ctrl tab next to GPS Mode Control, choose POTI 3. This assigns GPS to POTI 3 which is also channel 6 on the radio.

Under the Camera tab, just below the word Nick, choose POTI 4. Only nick needs to be assigned a POTI/channel as roll functions automatically from the FC board's gyro signals. By assigning a POTI/channel to your camera mount's nick servo you can manually adjust the camera angle up or down while the FC board also keeps it stable with gyro signals.

Under the Altitude tab next to the word Setpoint, choose POTI 5. This will assign the altitude hold function to POTI 5 which is channel 9 on the radio.

Once you've done this you can click the Write button on the bottom right of the Settings window and it will write the settings to your MK's flight control board and you'll hear three beeps to signal it's complete.

You can shut down MK Tool at this point and remove power from the FC if you'd like. You'll need your radio in front of you to continue with the next post.
 

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