7 Must-Know Tips for Getting the Most Out of ExpressLRS PWM Receivers

RCHobby Lab’s Author: Daniel Henderson
Reviewed by Kristen Ward
Updated on
Reviewed by Kristen Ward

Whether you’re outfitting a new fpv racing drone or upgrading the electronics in your rc rally car, compatibility with ExpressLRS is practically a must these days. This leading-edge control link system touts incredible range, near-latency-free video feeds, and bulletproof connectivity.

But while ExpressLRS works great with purpose-built flight controllers and electronic speed controls, fitting it into vehicles using old-school PWM components like standard RC servos can be tricky. Enter the ExpressRLS PWM receiver—your ticket to modernizing stubborn planes, cars, boats and more.

Equipped with the right settings and extensions, these powerful little modules can translate ExpressLRS’ futuristic control link into PWM signals your existing components can understand. Making them work does require some specialized know-how, however.

From essential failsafe options to receiver stacking to unlocking additional channels, this guide will cover 7 must-know tips for getting the absolute most out of ExpressLRS PWM receivers.

Let’s get to it!

1. Put Receivers in WiFi Mode to Access Advanced Settings

The tiny ExpressLRS PWM receivers offer a shocking range of tweakable parameters accessible through a built-in web server. But you’ll need to put modules into WiFi mode first before you can start dialing in settings for your specific application.

Here is the process for enabling WiFi mode:

  • Make sure your transmitter is powered off completely. The receiver needs to be on but disconnected from the transmitter to enable WiFi mode.
  • Power the PWM receiver by connecting it to a battery or ESC. The module will enter WiFi mode automatically after being powered on for 60 seconds without linking to a valid transmitter.
  • When WiFi mode activates, the LED on the receiver will change from a slow single blink pattern to a fast double blink. This means the internal access point has been enabled.
  • On your smartphone, tablet, or computer, scan for nearby WiFi networks. The receiver broadcast network will appear as “ExpressLRS-RX” followed by some digits.
  • Connect your device to the ExpressLRS-RX WiFi network using the default password: expresslrs
  • Open a web browser and navigate to to load the receiver’s built-in configuration panel

You should now have full access to tweak failsafe positions, output modes, channel mapping, and other parameters. Make your changes, save them, then power cycle the receiver to exit WiFi mode.

2. Set Up PWM Failsafe Positions

Unlike flight controllers and ESCs which have failsafe logic built-in, basic PWM servos need to be configured manually. This means telling the receiver what positions to drive connected control surfaces to if the link with the transmitter is ever lost.

Setting proper failsafe values is crucial for avoiding flyaways or runaways if you lose connection during operation. Follow these steps to dial in positions tailored to planes, multicopters, cars or boats:

  • In the receiver’s WiFi config panel, locate the failsafe position settings under the Model tab
  • For aircraft, set the throttle channel (usually CH3) to 1000 to kill power in the event of signal loss
  • For ground vehicles, center the throttle channel along with steering by entering 1500
  • Enter any other desired servo or switch positions for remaining channels
  • Save updated failsafe positions and exit WiFi mode

Now connected PWM servos and switches will default to sane, safe positions on disconnect instead of the last commanded values.

Note that failsafe settings can also be accessed directly from Transmitter menus in some cases without using WiFi. Consult your specific radio’s manual for details.

3. Lock Dynamic Power with Arming Function

Dynamic power adjustment is an awesome ExpressLRS feature that minimizes power draw by ramping output dynamically based on link quality. Output starts low when vehicles are near the transmitter then boosts automatically as range increases to maintain a solid connection.

But there’s a catch with PWM receivers—dynamic power will only activate when the system senses that the craft is armed. This arming state is triggered by setting AUX1 (usually channel 5) to its upper range.

For aircraft with dedicated arming switches this is no problem. But many ground vehicles have no such toggle. Without the armed signal, the receiver stays stuck at low power limiting the functional range.

The simplest fix is forcing channel 5 permanently high with a fixed 1500-2000us pulse width on the transmitter. This keeps the receiver armed so dynamic power functions normally.

An alternative is remapping the arming channel entirely in the receiver settings to an unused output, freeing up channel 5 on the transmitter stick for other uses.

Either way, make sure the receiver shows the “Armed” status on-screen or dynamic power will never engage!

4. Understand PWM Packet Rates

A key way ExpressLRS achieves incredible sub 2ms latency for flight control is by sending bare minimum packet data optimized for control bandwidth not telemetry. For main sticks, full 1000Hz resolution is transmitted.

But to conserve bandwidth, auxiliary channels may transmit at a lower packet rates and reduced resolution when set to the default “Wide” switch mode. This scales channel precision and update rate to match typical use driving switches rather than proportional controls.

If you need increased packet rate/precision on PWM channels for smooth servo operation or other needs, change the receiver switch mode to “Full”. This forces 100Hz or 333Hz updates on all channels at the cost of some extra latency. Adjust to fit your vehicles requirements.

Just realize at full resolution, the maximum usable receiver range will take a notable hit. As will battery life. Find the sweet spot between channel resolution, latency and range that works best for your models.

5. Stack Multiple Receivers for More Channels

Did you know ExpressLRS transmitters can command up to 16 individual servo channels? Even better, you can bind multiple PWM receivers to the same transmitter to unlock the full channel count.

This means adding extra receivers lets you expand available PWM outputs far beyond the limit of any single module.

Here’s an example:

  • Bind a 5 channel PWM receiver to channels 1-5
  • Bind a second receiver to channels 6-10
  • Connect both receivers simultaneously and you now have 10 PWM channels available between the two

To pull this off without chaos:

  • Set the first receiver to provide telemetry normally
  • Disable telemetry completely on the second receiver (and any others) to avoid conflict
  • Power up receivers simultaneously after binding

Using this technique you can keep stacking PWM receivers, accessing up to 16 individual servo channels from a single transmitter!

6. Choose PWM Frequency for Servos

Unlike regulated digital servos, simple hobbyist servos typically expect 50Hz PWM inputs for smooth rotation control. But in some cases, tighter regulation is needed.

ExpressLRS receivers can output a choice of four PWM frequencies to match the requirements of connected devices:

  • 50Hz: Standard for general RC servos
  • 150Hz: For higher performance digital servos
  • 333Hz: To drive the latest high-speed FBL2 digital servos
  • 1000Hz: Special mode to directly control some brushless ESCs

Select the frequency that aligns with your servos or other actuators for glitch-free operation. Change modes in the receiver WiFi configurator under the “Output Mode” heading to match device specs.

This also applies when using ExpressLRS PWM output to drive external interfaces like flight controllers, servo decoders and mixers. Set PWM rate to ensure stability.

7. Remap Channels to Fit Unexpected Needs

Despite best efforts mapping components to intended servo channels, sometimes situations arise requiring outputs to change.

For example, swapping which stick axis drives throttle when converting an airplane to a multicopter configuration. Or working around busted PWM lines by re-assigning channels.

With an ExpressLRS receiver, remapping signal outputs to different pins is as easy as picking new assignments in the channel output map. No soldering or hardware mods needed!

Access the mapping table under the “Output Mapping” title in WiFi configurator. Then simply assign each connected PWM wire to whatever transmitter control channel is desired. Hit save and the receiver will now drive connected lines with newly assigned channels.

This flexible channel targeting makes it easy to quickly reconfigure servos for failover or to better fit unorthodox vehicle layouts. Especially useful for complex craft with lots of powered elements like sensor gimbals, multiple ailerons or rudder channels.

Final Words

In closing, by taking advantage of these 7 key tips you can unlock the full potential of ExpressLRS even with legacy PWM-based vehicles. Customizable failsafe positions, flexible channel mapping, and receiver stacking give new life to stubborn old platforms. While fine tuning packet rates, PWM frequencies and power modes helps dial in top-notch control response.

Give the ExpressLRS PWM receivers a try and breathe new performance into temperamental gas cars, scale turbine models even fireproof racing drones using our guidance. Just bear in mind the essential settings that translate bleeding edge protocol perks into real world PWM compatibility.

So get out there and enjoy phenomenal range, bulletproof response and next-level speed thanks to customizable ExpressLRS integration with existing equipment. Happy flying and driving!

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Written By Daniel Henderson

My name is Daniel Henderson and I'm an avid FPV pilot and videographer. I've been flying quadcopters for over 5 years and have tried just about every drone and FPV product on the market. When not flying quads, you can find me mountain biking, snowboarding, or planning my next travel adventure.

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