‘How do I bind my radio to my quad?’. This is easily the most asked question for new pilots. Don’t feel bad, the process itself has quite a few steps. But if you do them right, you will be in the air in no time.
Radio and OpenTX set-up
- Depending on the radio you have, the binding process will be slightly different. In this guide we will focus on the Frsky QX7, running the operating system OpenTX, using an SBUS XM+, RXSR or SPI receiver.
- Don’t worry if you have an Xlite, X9d or x9 lite – all FRSKY radios run OpenTX, so the process will be pretty much exactly the same. The only thing that will change are the buttons you need to press to use the main menu on your radio. You can also use this guide to bind using a Jumper or Radiomaster radio.
- Create a new model for a quad on your radio. Leave everything stock.
- Enter the main set-up menu by pressing the center button on the left hand side of the QX7. Press PAGE once to get to page 2/12, scroll down to the bottom.
- Here is where we set up the parameters for any given receiver. See the Mode option under Internal RF? Let’s say we are using the XM+ receiver, which has no telemetry – you would select d16/channels 1-8 – telemetry off.
For a receiver with telemetry, like the RXSR, you would select d16 – channels 1-16 – telemetry on. This screen also has the bind [BND] command we will need to use to put the QX7 into bind mode. More on that later.
Betaflight set up
- On the Configuration tab, scroll down to Receiver. Select – Serial-based receiver (SPEKSAT etc) AND SBUS in the respective drop-down menus. Save.
- On the Receiver tab, in the Channel Map section, select Spektrum / Graupner / JR. This will change your receiver to match your radio’s default Mode 2 set-up. (TAER or Throttle + Yaw on the left stick, Pitch + Roll on the right. Save
- On the Ports tab, enable Serial RX on the UART you soldered your SBUS wire to. For example, on an F4 Mamba MK2 stack, you need to use the dedicated SBUS pad. This is RX 1 on the Mamba stack, which is UART 1 on the Ports tab in betaflight. All F4 flight controllers only have one dedicated SBUS pad. If you have an F3 or F7, it doesn’t matter which RX pad you use to connect SBUS to. Don’t forget to save.
Get Ready for Binding
Binding is much easier than you think. But first, a few key points to take note of:
- These receivers only take 5v. Make 100% sure it is wired correctly to a 5v pad on your Flight Controller. Use the manuals provided at the end of this guide to ensure you have the wires going to the right places!
5v from receiver to 5v on FC. Ground from Receiver to ground on FC. Sbus/signal wire from receiver to RX pad on your FC. You can use any ground and any 5v on the FC.
- Take your time soldering. These Receivers are TINY. Use something like blu-tac to secure the receiver while soldering. Make sure you have made a solid connection on all pads. If one fails, your quad will fall from the sky.
- Use heat shrink. After you have finished binding, make sure to go back and heat shrink the receiver. You need to put this on before soldering 😉
Clear heat shrink is the best because you can still see the lights on the receiver. This is especially handy if your receiver dies, or isn’t connecting with your flight controller for some reason. If you don’t have heat shrink handy, clear tape works in a pinch. It just doesn’t look as good and has poor heat resistance. We do this to avoid the receiver shorting out on the frame or another component.
- Ask a friend for help! The hardest part of binding is plugging in a power source while holding the microscopic bind button on the receiver. This process becomes much easier if you ask someone to do one of those things, while you do the other.
The Binding Process
- Go to the setup screen, page 2/12, like we did in the Radio set-up section.Set d16. Leave channel range alone for now.
(take the time to set the Failsafe option to No Pulses – this will setup your Failsafe to shut off your quad if it loses signal for long enough.)
- Where it says RxNum – XX [Bnd] [Rng] – highlight BND – press enter. The radio is now in bind mode. You should hear an intermittent chirping sound to indicate it is in binding mode. If you are using a Jumper or Radiomaster radio, put it in bind mode AFTER step 3 below.
- Press and hold in the tiny bind button on the receiver. Plug in a lipo battery, or have someone else plug one in, all the while still holding the bind button in on the receiver.
- Once you have completed the step above, you can release the bind button and exit out of binding mode on the radio. Unplug then re-plug in the battery. If binding was successful, an XM+ will show the solid green light, the RXSR will show green and solid blue. You should now go and test if everything is working correctly by going to the receiver tab Betaflight. Plug in a battery and check that all the channels respond when you move your sticks. If your channels are in the wrong order, simply change the default AETR1234 to something like TAER1234. You can just type in the new order directly and then hit save.
- XM+ – flashing red = not bound/no connection to radio. Green and Red lights = should see this after binding, before unplugging the battery. Solid Green light = binding was successful/connected to radio.
- RXSR – flashing red + solid blue = not bound/sbus mode. Green + Solid blue = binding successful in SBUS mode.
Binding Whoops with SPI and CLI
The bind buttons on whoop/toothpick AIO boards can be a nightmare. You can actually bind SPI receivers, like on the Crazybee boards, by using a CLI command.
Go the the CLI tab in betaflight.
Depending on the version of betaflight you are running, you need to use a different bind command.
- Betaflight 4.1 – bind_rx – hit enter
- Betaflight 4.0.x – bind_rx_spi – hit enter
- Betaflight 4.0 – bind – hit enter
- Betaflight 3.5.x – frsky_bind – hit enter
Your quad will now be in bind mode. Follow the same procedure for normal binding after this. Just ignore having to hold in a bind button/plug in a battery. The betaflight set-up is slightly different. On the Config tab in betaflight you need to select SPI RX support instead of Serial-based receiver. The other drop down menu will still need to be SBUS.
So I’m bound, now what?
You now need to set up the Modes tab in betaflight, as well as adding them to your radio. Please watch the video on Modes by Project Blue Falcon (linked at the end of this article).
After this, go to betaflight, Receiver tab. Plug in a lipo battery. If everything is bound and set-up correctly, you should see movement on the TAER channel bars when you move your sticks.
It’s not working – Troubleshooting
I don’t get the correct lights to indicate binding was successful.
- Try the binding process again. It can sometimes be tricky to get the right timing, having to hold the bind button and plug in a battery, especially by yourself.
Some Flight Controllers will actually power up the receiver enough to be able to bind it. And really, any 5v and ground you give the receiver will power it. You don’t even need the signal wire soldered up to bind. If you can power it this way, it can be a much easier way to bind your receivers.
- Triple check your radio set-up. Are you in bind mode? D16? Is your radio chirping at you?
- Triple check your wiring. Are you getting any lights? No lights at all could mean it is fried…resolder the ground and 5v pads.
- Are you using a fully charged lipo battery? Sometimes poorly balanced batteries can cause headaches with even simple stuff like binding…this one is rare however.
- The last chance fix could be reflashing. But only resort to this if you have tried everything else. Flashing is a bit of a pain. For example, if you have an FCC radio, you need an FCC compliant receiver. If you are in the EU, you will probably have an EU version, and therefore will require an EU compatible receiver. This video will walk you through the basics of flashing if you think you have compatibility issues. You basically need to wire up your receiver to a servo connector and then plug that into 3 pins on your radio. Check the end of the article for videos on QX7 and the x9d.
My stick’s aren’t registering on the betaflight Receiver tab.
- Double check you have set up Betaflight correctly. Did you save after each change?
- Make sure you are using a well balanced lipo battery.
- Check the lights on the receiver. Solid green for XM+ and Green + Blue for RXSR.
- Re-flashing the receiver might be your only option at this point.
CHECK YOUR FAILSAFE
Once you are bound and have your switches set-up and working, you need to check that your Failsafe is working correctly.
- Take off your props, plug in a battery, arm your quad.
- Turn off your radio.
- The quad should almost instantly shut down the motors to a complete stop. A failsafe can come out of no-where, so you want to know your quad is going to drop, rather than keep flying. You risk harm to yourselves and others if your failsafe isn’t working reliably.