• Welcome to RCTalk! 🚀

    Join the #1 RC community where hobbyists connect, share, and get expert advice on RC cars, trucks, boats, drones, and more!

    • ✓ Friendly & passionate RC enthusiasts
    • ✓ RC tips & troubleshooting
    • ✓ Buy, sell & trade RC gear
    • ✓ Share builds & upgrades

Radiomaster MT12 - Review and Guide

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
Hey guys!
If you’re wondering “which protocol do I use to bind my receiver?”this should help!

MT12 Protocols Guide: What to Use for Different Receivers
______________________________________________________________________________

1. ELRS (ExpressLRS) – Modern, Open-Source, Long Range​

MT12 with an internal ELRS module.

Use for:
  • RadioMaster ER/EP/ES/ELRS series receivers
  • BetaFPV ELRS, Happymodel ELRS, Flywoo ELRS, TBS ELRS, and other “ExpressLRS” branded receivers
How to bind:
  • In the radio: Select CRSF protocol in your Model -> Setup
  • Receiver shall be flashed with matching ELRS version and bind phrase
  • Binding phrases are configured when connected via WiFi to the TX internal module and RX
MT12 menu:
  • Internal RF: ELRS / CRSF
______________________________________________________________________________

2. Multi-Protocol (4-in-1) Module – For Legacy & Brand Receivers​

If your MT12 has an external 4-in-1 or CC2500 multiprotocol module (plugged into the JR bay), you can bind to a huge list of other receiver types!

Use for:
  • Flysky (AFHDS/AFHDS2A)
  • FrSky (D8, D16, LBT, ACCST)
  • DSM2/DSMX (Spektrum)
  • Futaba SFHSS, Hitec, Radiolink, Redcat, and more
How to bind:
  • In the radio: Set External RF to “MULTI,” then pick the correct protocol (e.g., FrSky D16, Flysky AFHDS2A, DSMX, etc.)
  • Put receiver in bind mode, start bind from radio menu
MT12 menu:
  • External RF: MULTI → Choose correct sub-protocol
______________________________________________________________________________

3. PPM/SBUS/IBUS Receivers (Very Legacy, Not Recommended)​

Some old RTR vehicles or flight controllers use analog PPM, IBUS, or SBUS.

Use for:
  • Older Flysky/FrSky/Turnigy receivers
How to bind:
  • If using an external multiprotocol module, select matching protocol
  • PPM/IBUS/SBUS will often “just work” if matched to the right brand in MULTI
______________________________________________________________________________

4. How to Know Which Protocol to Use?​

  • Check your receiver’s brand/model
    • If it says ExpressLRS, ELRS, or CRSF: Use ELRS (internal module, CRSF protocol)
    • If it says Flysky: Use AFHDS2A in MULTI
    • If it says FrSky: Use D8, D16, or ACCESS in MULTI (choose matching mode)
    • If it says Spektrum: Use DSMX/DSM2 in MULTI
    • If it’s another brand, check for supported protocols in the Multi-Module documentation (link here).
______________________________________________________________________________

Tips & Tricks​

  • If you’re just starting out: ELRS (ExpressLRS) is the best for future-proofing, range, and support. The internal module on the MT12 does it all for surface and air.
  • If you need legacy compatibility: Add a 4-in-1 Multi-Module to the external bay—then you can bind to almost anything.
  • Binding can be confusing at first: Always match protocol in your radio to your receiver’s type, and check firmware versions (for ELRS).
  • OpenTX/EdgeTX model settings: Always check which module (Internal or External RF) is “ON” for your model.

MT12 - Protocols.webp
 
This is a must watch, it's for pilots :-) but applies to MT12 as well - these are EdgeTX universal principles - if you are not fully familiar with EdgeTX yet, watch it first before you get to my next post.

 

🟢 MT12 Programming Basics: Inputs, Mixes​

______________________________________________________________________________

1. Inputs – “What Are They?”​

Inputs are the raw controls you use—sticks, triggers, pots, or sliders.
Think of them as “what you touch” (throttle, steering, knobs, sliders).
When we'll get to Advanced Programming, we'll also include Global Variables in Inputs.

Examples:
  • Input 1: Typically Steering
  • Input 2: Typically Throttle
  • Input 3: High/Low Gear
  • Input 4: Drag Brake
You usually won’t need to deal with Inputs unless you want to change expo or sensitivity for a stick/knob.
______________________________________________________________________________

​

2. Mixes – “Where the Magic Starts”​

Mixes decide where those inputs go, and what happens to them before they reach your car (receiver channels).
  • Each channel (e.g., CH1, CH2, etc.) has a Mix line that tells the radio what source controls it, and how.

What does a Mix do?​

  • Assigns an input or switch to a specific channel.
  • Can change the output (reverse, limit, curve, offset, or use a logical switch).
  • Mixes let you make advanced features (like 4WS, dual rate, throttle cut, lights, winch, etc.).

Example 1: ARM / DISARM​

CH5 (Per ELRS documentation - this is where you set your ARM switch) -> Source = Logical Switch (eg. L01)
and
CH2 (your Throttle channel) -> Weight = G1 (for Drive Modes) and Switch = L01 (to link ARM / DISARM)

We'll talk more about the ARM switch in a separate post and since we've touched the Logical Switch topic, it'll be the next post.
 
Last edited:

🟢 MT12 Programming Basics: Logical Switches​

Yeah.. Logical switches? Oh, you mean that thing that makes more sense after three espressos and a YouTube rabbit hole?
Logical switches can sound intimidating, but once you get the hang of them, you’ll wonder how you ever lived without them! :cool:

Here’s what they do, and how to use them (even if you’re not a code wizard):

What Are Logical Switches?​

Logical switches are “virtual” switches that react to conditions you set—like a secret helper inside your radio.
They can trigger actions (e.g., cut throttle, sound a buzzer, change drive modes) based on stick position, timer, sensor value, or other switches.

Think of them like “if this, then that” (intelligent) buttons for your RC!

Useful examples:​


1. ARM / DISARM Switch​

  • Why: Starts your rig disarmed and Instantly disables throttle (or all controls) no matter what - ideal for setup, quick repairs, handing your control to your kid or friend or emergencies.
  • How: One switch (or combo) must be ON for throttle mix to be active.

2. Automatic Lights (or Sound)​

  • A. When It Gets Dark
    • Why: Night drive realism—headlights on automatically at sunset.
    • How: Use a light sensor on an input or set a timer (e.g., after 6pm, logical switch turns lights ON).
  • B. When You Reverse
    • Why: Brake/reverse lights just like a real car.
    • How: Logical switch detects negative throttle and turns AUX channel on.

3. Custom Drive Modes (Crawler/Cruise/Bash)​

  • Why: Instantly swap steering rates, throttle curves, or drag brake for different terrains.
  • How: Use a 3-position switch (e.g., SA) and logical switches to change rates, endpoints, or activate mixes.

4. Winch or Accessory Logic​

  • Only When Stopped:Prevent winch from running while moving.
    • How: Logical switch only enables winch channel if throttle is at zero and another switch is ON.
  • Auto Winch Out/Winch In: Tap once to pull, twice to let out, etc.

5. Self-Right (Turtle Mode) for Rock Crawlers​

  • Why: Flip your rig back over after a rollover, but only when throttle is at zero.
  • How: Logical switch enables turtle mix when stopped + special button press.

6. Automatic Cooling Fan​

  • Why: Only run fan when ESC temp or current is high, saving battery and noise.
  • How: Logical switch reads telemetry sensor; turns fan on if temp > 60°C.

7. Low Voltage Alarm or Throttle Reduction​

  • Why: Protect your LiPos by warning you or limiting throttle when voltage drops.
  • How: Logical switch triggers a beep or cuts max throttle when telemetry voltage < 3.5V/cell.

8. Lap Timer or Pit Lane Speed Limiter​

  • Lap Timer: Start/stop timer with a trigger or when crossing a sensor.
  • Pit Limiter: When you hit a switch, throttle is capped for pit lane realism.

9. Dual Rate or Expo Switches​

  • Why: Instantly swap between soft (cruise/crawl) and aggressive (race) steering or throttle curves.
  • How: Logical switch activates alternate expo or endpoints.

10. Automatic Camera Gimbal Leveling or FPV Switch​

  • Why: Keep onboard camera level only when not turning.
  • How: Logical switch enables gimbal channel only if steering input is near center.

11. Lost Model Alarm / Beeper​

  • Why: Beep or flash lights if you lose your car (out of range, stopped for X seconds, or on command).
  • How: Logical switch based on inactivity or RSSI.

12. “Burnout” or “Drift” Button​

  • Why: Instantly lock rear diff or activate special ESC mode for burnouts.
  • How: Logical switch and mix send command to diff lock/ESC channel when button is held.

13. And many, many more...! Let me know your ideas, we can create a tutorial.​


Example 1: ARM / DISARM Switch​

Let’s create an ARM / DISARM switch, mapped to switch SD:

1. Go to Logical Switches on your MT12
  • Find an empty logical switch slot (L01 for this example)
2. Set up the switch:
  • Function: Stky
  • V1: SD (down arrow)
  • V2: SD (down arrow)
3. Go to Mixes
  • Add L01 to CH5
  • Name it "Armed"
  • Source = L01
  • Switch = L01
and
  • Add to CH2 (as your Throttle)
  • Switch = L01

​

Super easy, wasn't it?​

Now you have your MT12 better and safer than before - Throttle works only when MT12 is "Armed". No more accidental throttle blips.

It's important to say that there are usually more ways how you can implement functions! This is only one example.

Next: Special Functions​

We'll add Sound and LED Lights to your Logical Switch.
 
Last edited:

🟢 MT12 Programming Basics: Special Functions​

Now that your MT12 is smarter and safer with logical switches, let’s give it some personality!

Special Functions let you do many things, we'll use it to trigger sounds and control LEDs whenever a switch (it's a physical button but in our case a logical switch) activates.

Play a Sound When Armed/Disarmed​

1. Go to Special Functions​

2. Pick two empty slots​

3. Set up the sound:​

  • Switch: L01
  • Action: Ply Trk
  • Parameters: Choose your audio file (e.g. armed)
and
  • Switch: !L01
  • Action: Ply Trk
  • Parameters: Choose your audio file (e.g. disarmed)

Use LED Lights to Show Armed/Disarmed​

1. Pick two empty slots​

2. Set up the LED:​

  • Switch: L01
  • Action: RGB leds
  • Parameters: Green
  • On: Check
and
  • Switch: !L01
  • Action: RGB leds
  • Parameters: Red
  • On: Check

Your MT12 now tells you if it's armed or disarmed and it's easy to see the status based on the LED light color.

Once you combine Logical Switches with Special Functions, your MT12 becomes a true smart controller - in this case safer, more interactive and more fun!
 
Great stuff, I haven't watched or read most of this, but I am very happy you have taken your time to share this with us. I'm balls deep in yard work or I would tinker with my radio
 
Hey guys, glad you like it! I had fun putting the info together. To be honest, programming some functions (such as 4WS) is like reinventing the wheel 🙃. But then, when you want to add your own features, the MT12 simply can’t be beat!

Since my SCX6 often serves as a rescue car, I'm thinking I'll add a crane and it can use the throttle as the winch control—I think it’ll be super comfortable. Flipping a switch disables drive throttle and remaps the throttle stick to control the winch channel - (forward = winch in, reverse = winch out) - layered Logical Switches. And in rescue mode, the MT12 can even flash the “Police LED” - Special Function.
 
Arma said:
Hey guys, glad you like it! I had fun putting the info together. To be honest, programming some functions (such as 4WS) is like reinventing the wheel 🙃. But then, when you want to add your own features, the MT12 simply can’t be beat!

Since my SCX6 often serves as a rescue car, I'm thinking I'll add a crane and it can use the throttle as the winch control—I think it’ll be super comfortable. Flipping a switch disables drive throttle and remaps the throttle stick to control the winch channel - (forward = winch in, reverse = winch out) - layered Logical Switches. And in rescue mode, the MT12 can even flash the “Police LED” - Special Function.
Click to expand...
I like how you can set up these RGB's, it is way cool.
 
Spksh said:
You’re all awesome, thanks for sharing all this. I guess I have something else to add to the shopping list…
Click to expand...
I was initially a bit overwheled with how complex EdgeTx is to learn. But I recently started testing AI to see if it could help figure out some setups.

My initial request for a no-prep model setup:
Screenshot_20260126_044359.webp


AI Response:
Screenshot_20260126_044423.webp
Screenshot_20260126_044501.webp
Screenshot_20260126_044525.webp
Screenshot_20260126_044557.webp
 
This is just free AI. So it may have errors. But the bulk of the model setup is done. It's just test and tune after entering all that into the radio.

I am sure AI could actually spit out a file with all that in a model you can just put on a micro sd and load into the Tx easy peasy.

This is all kinda taking the easy way out by using AI, but it is actually the fastest way to learn how to create exactly what you want to do, as opposed to using someone else's model setup and having to try to understand their logic to make your changes.

So after all that we can move onto the really fun stuff. LUA scripts. For this setup, I would probably want to completely redo the user interface on the main screen. As soon as this model is selected, the LUA script creates sections on the screen to display the 3 drive modes with relevant info, along with various other things like telemetry info.

Burnout mode could display the timer showing time left for the burnout, motor/ESC temp, and if you were an electronic wizard, you could get the motor load with load sensor, and create a "traction curve" based on load to show you when your tires are ready to go. Heck, you could have the motor stop when it reaches a specific losd instead of using a timer 😁

The center section could simply say driving mode 2 and display a staging symbol. Part of that could be split off for a steering sensitivity setting, controlled by one of the knobs by the steering wheel. There could also be a telemitry display showing motor and esc temps here. Stall the other guy til your temps come back down. Toss a couple nuts on the ground - "hey, those yours"? 😆

Some other things:
The three stage launch window could display some more telemetry. With the combination of RPM telemetry from the ESC or external RPM sensor, and an ELRS receiver equipped with a BMI270 chip to measure accelleration, you could calculate wheelspin at the various stages pretty accurately and display it on-screen. Or hell, even have your throttle automaticcally adjust to wheelspin. You could also calculate MPH all the way down the track and log the run.

The EdgeTx firmware literally gives you the ability to take nearly any crazy idea in your head and make it happen.
 
Last edited:
Spksh said:
Yeah, that's what I'm getting at. Are the advanced programming options here (e.g. scripts to change input curves on demand) seen as driver aids?
Click to expand...
I'm not sure what you mean exactly, but i do a lot more tuning of my throttle and brake in my radio than the ESC. it's way easier for one thing. Adjusting expo, dr, etc. for throttle isn't any more cheating than adjusting it for steering. Now a gyro, or something that is measuring forces and actively adjusting your inputs would absolutely be cheating. afaik the mt12 only takes battery telemetry and I'm not sure how useful that would be in cheating.

I guess you could use one of their aviation receivers for more gyro-like controls in all axis maybe? but i think you'd have trouble fitting an aviation receiver in some race buggies and stuff and it might cause a lot of questions in tech, plus experienced people would probably call foul based on the way it performs. Don't think you can easily hide that stuff from knowledgeable people.
 

RC Builds

Back
Top