Binding & Mixing Guide for Combat Robots with the Devo 7E & Flysky FS-i6 transmitters

Binding your receiver to your transmitter and setting up your drive mixing can be one of the most complicated parts of building a combat robot! Follow this guide to help you get this set up, applicable to all weight classes. Any questions or feedback please email us at bristolbotbuilders@gmail.com

Transmitter

For robot combat we typically use a ‘mode 2’ transmitter, which means the stick directions are labelled the following:


If you’ve got a mode 1 transmitter the only difference is the Throttle and Elevator sticks are swapped.
In Robot Combat the typical transmitter setup is using:

  • Elevator (up/down on right stick) for robot’s drive forwards/backwards
  • Aileron (left/right on right stick) for robot’s drive left/right
  • Throttle (up/down on left stick) for robot’s weapon control.

You can set up to drive your robot however you like, but we’ll use this layout in this guide.

Please note: if you’ve bought a Devo 7E, you’ll need to flash it with deviation so it can bind with DSM2 receivers. Nuts and Bots have written an excellent guide here.

Receiver

When your receiver and transmitter are connected if you press up on the elevator stick of the transmitter, the receiver will send that signal out of the elevator pin.
You’ll need to find the following pins on your receiver:

  • positive (+ve) – usually red wires
  • ground (GND) – usually brown or black wires
  • signals (PWM) – usually yellow, green or white wires.
    4 signals we typically use on receivers that match up to the sticks on the transmitter diagram (above):
    • Throttle (THR)
    • Aileron (AIL)
    • Elevator (ELE)
    • Rudder (RUD)

Here’s the pinout for the two receivers that can be included in the kit. left side: DSM2 receiver, right side: Flysky receiver.

If you’ve got a DSM2 CM421 receiver you’ll want to plug the drive ESC(s) in to Channel 2 and 3.
If you’ve got a Flysky FS2A receiver you’ll want to plug the drive ESC(s) in to Channel 1 and 2.
Make sure to match up signal, positive and ground wires of the motor servo connector with the pins on the receiver.

Please note: With the Flysky FS2A receiver you can either chop off the motor servo connectors and solder the wires directly to the pinholes or you can solder the included receiver pins on to the receiver (picture below) and plug in the servo connectors.

FS2A 4CH AFHDS 2A Mini Compatible Receiver PWM Output for Flysky ...

In the picture below you can see the two motors plugged into the DSM2 CM421 receiver channels 2 and 3 – the ground (black wire) is at the bottom, positive (red) is in the middle, and the signal (green) is at the top. This is the same for the Flysky FS2A receiver, just plugged into Channel 1 & 2.

Binding the receiver

Binding with the DSM2 receiver & Devo 7E Transmitter:

  1. Plug the bind plug into the bind channel. (The bind plug wire connecting the bind signal and ground)
  2. Turn on Devo 7E and make sure you’re on the main screen. Press ENT button.
  3. With Model menu highlighted press ENT button.
  4. With Model setup highlighted press ENT button. You can change ‘Models’ for different receivers/bots at this point by:
    1. With < Load… > highlighted press ENT button
    2. Use UP+ and DN- buttons to browse models
    3. Press ENT button to load the model.
  5. Press DN- button until you see < DEVO > [ Bind ]
  6. With < DEVO > highlighted press R+ button until it says < DSM2 >
  7. Press DN- button until Fixed ID [123456] is selected and change this to any number you like but the default 123456. Use UP+, DN-, R+, L- and ENT buttons to select numbers and once you’ve typed it in press ENT on [ DONE ].
  8. Press UP+ button so [ Bind ] is highlighted
  9. Make sure all sticks are in default positions – all centred and Throttle at it’s lowest position. This is for failsafing when the transmitter is off.
  10. Turn on the receiver using the switch. The receiver light will flash on and off rapidly. Press ENT button on [ Bind ] and wait for the receiver light to go solid (ignore the countdown) then press ENT button again.
  11. Now if you move the right stick up/down left/right the motors should move. You have bound the receiver to the transmitter! If they do, switch off the circuit and remove the bind plug from the receiver. If not check through the instructions again.

Binding with the Flysky receiver & i6 transmitter:

  1. Turn on the transmitter and select the model slot you want to use for this receiver / bot by doing the following:
    1. Press and hold OK button to see System Setup Menu. Press OK button.
    2. Press UP/DOWN buttons to select Model Select and press OK button.
    3. Press UP/DOWN buttons to select the model you want to use.
    4. Press and hold CANCEL button to load model.
    5. Now turn off transmitter.
    6. Hold down the bind button on the receiver whilst turning it on with the switch. The blue light should be flashing rapidly, meaning it’s in bind mode.
    7. Hold down the bind button on the transmitter while turning it on. You will see ‘binding’ on the screen
    8. When the receiver is flashing slowly turn the transmitter off and on again.
    9. You should see the blue light on the receiver go solid.
    10. Now if you move the right stick up/down left/right the motors should move. You have bound the receiver to the transmitter! If not check through the instructions again. Switch off the circuit.

Failsafing

Failsafing is when your transmitter is turned off your robot’s drive and weapon will stop. This is an important safety feature.
Failsafing on Flysky FS2A receiver (July 2022 and newer models – see below for how to check):
You can set the failsafe on the transmitter – you must set each channel individually. Example for FS-i6:
Good video here. With your robot on, go to Menu > System Menu > RX setup > Failsafe
Turn on failsafes for the channels you need – in this example: Channel 1 & 2 for drive are set near middle and Channel 3 in this case is set low for spin up on throttle. Once you’ve set them up hold down CANCEL button to save. Test your failsafes are working (turn off transmitter)
The “all channels” failsafe in the menu will not work for this receiver.

Failsafing on Flysky FS2A receiver (pre July 2022 models – see below for how to check):

  1. Turn on both your receiver and transmitter.
  2. Set your transmitter’s right stick to the middle and push the left stick to the bottom.
  3. Hold the bind button on the receiver, the blue light will flash quickly several times then go solid. –Note: this is just the failsafe for this model of receiver, if you have a different one, failsafe setup may be different. There’s a failsafe option in the transmitter menu too.

New and old versions of flysky receiver
New style have a larger square chip vs smaller rectangular on old (pictured)

Failsafing on DSM2 receiver

Hopefully you’ve bound your receiver to your transmitter with all the sticks in their centre positions and throttle down. When you turn off the transmitter this should be the value the receiver takes – so you should see no movement from your bot. If this isn’t the case, rebind with sticks in neutral positions and retest.

Mixing on the transmitter

If you are not running a dual ESC with built in mixing (most common at antweight) then read on, otherwise you’re done!
Currently you have one motor driven by Elevation(right stick up/down) and one driven by Aileron (right stick left/right). We need to set up mixing so forward on the stick will drive the robot forward, left on the stick will turn the robot left etc. We can do this with mixing. We need the motors to move these directions when we move the right stick:

So when we move ELE (up/down) we need to also drive the AIL motor in the same direction as the ELE motor.
And when we move AIL(left/right) we need to move ELE motor in the opposite direction to the AIL motor.

To set up Mixing on Devo 7E:

  1. Turn on Transmitter and press ENT button
  2. With Model menu highlighted press ENT button.
  3. Press DN- button so Mixer is highlighted and press ENT button.
  4. Find the AIL channel and press ENT button. Change Reverse < Normal > to Reverse < Reversed> using R+ and L- buttons. Go back out of this menu with EXT button.
  5. Press DN- button to highlight the [ Simple ] button next to AIL and press ENT button.
    1. Use L- and R+ buttons to change < Simple > to < Complex >
    2. Use UP+/DN- buttons to highlight Mixers < 1 > and use R+/L- buttons to change it to < 2 >
    3. Use UP+/DN- buttons to Check that Page 1 has the following settings:
      Mux: replace
      Src: AIL
    4. Use UP+/DN- to select Page and use R+/L- to switch to Page 2.
      Mux: add
      Srx: ELE
    5. Press EXT to go back to mixer menu
      So overall the AIL settings are: !AIL complex, 2 mixers, page 1: replace AIL, Page 2: add ELE
  6. Press DN- button to highlight the [ Simple ] button next to ELE and press ENT button. Repeat the steps above but with different settings: ELE: complex, 2 mixers, page 1: replace ELE, Page 2: add !AIL
    the “!” means reverse – to do this highlight the Src [ AIL ] and hold down ENT button so it says Src [ !AIL ]
  7. Give this a test with your robot. Is forward, backwards, left and right working as expected? if not you may need to reverse the direction of the sticks:
    1. If forwards/backwards is the wrong way round: On the main mixer menu select [ ELE ] and change Reverse < Normal > to Reverse < Reversed>. Test this on the robot.
    2. If left/right is the wrong way round: Set [ AIL ] on main mixer menu to Reverse < Reversed>.
      It may take a bit of trial and error but you should be able to get forwards backwards left and right drive with the right stick of your controller.

To set up Mixing on Flysky i6:

  1. Turn on Transmitter. Press and hold OK button to open menu. Press UP button so you see Functions setup and press OK button.
  2. Press DOWN button until you have Elevon selected and press OK button.
  3. Press OK button so it says Elevon On. Hold CANCEL button to save.
  4. Now turn on your robot and test it out. Here are the things to check, firstly for forwards on the stick one of the following will be the case:
    1. Is forwards on the stick turning the robot? Then go out of the Elevon menu and go up to the Reverse menu and reverse either channel 1 or 2 so the stick makes the robot go forwards/backwards – if it is now forwards is backwards, go to the Elevon menu and set CH1 to -100%, if forwards is forwards set it to 100%. Hold CANCEL button to save.
    2. Is forwards on the stick forwards for the robot? Then use UP/DOWN buttons to set CH1 to 100% – this is setting it to max speed, you can reduce this if you prefer. Hold CANCEL button to save.
    3. Is forwards on the stick backwards for the robot? Then use UP/DOWN buttons to set CH1 to -100% (negative) and see if forwards on the stick is now forwards for the robot. Hold CANCEL button to save.
  5. Now let’s test for turning, using left/right on the stick, one of the following will be the case:
    1. If left on the stick is forwards/backwards on the robot. Then go out of the Elevon menu and go up to the Reverse menu and reverse either channel 1 or 2 so the stick makes the robot turn – if it is now left turns right, go to the Elevon menu and set CH2 to -40%, if left is left set it to 40%. Hold CANCEL button to save.
    2. If left on the stick turning the robot left? Then use UP/DOWN buttons to set CH2 to 40% – this is setting a gentle turning speed, you can make this faster or slower. Hold CANCEL button to save.
    3. If left on the stick turning the robot right? Then use UP/DOWN buttons to set CH2 to -40% (negative) Hold CANCEL button to save.
  6. Hopefully the sticks now go in the direction you want. You can now tweak these with the Subtrim menu to get the robot driving how you’d like.

Any questions please email us at bristolbotbuilders@gmail.com or post in the facebook group!

Thanks for reading 🙂
– Joe