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FrSky R9|RXSR Pilot Flight Control

The FrSky Pilot series flight controller is an All-in-One module that supports comprehensive flight control functions with pre-installed powerful INAV (The support of other open-source software like Ardupilot and Betaflight are ongoing.) and F.Port 2.0 software. This control system is targeted towards RC hobby enthusiasts who are looking for a complete system combining power management, a powerful graphic FrSky OSD, and plenty of IOs.


The R9/RXSR Pilot is comprised of a three-layer stack:

1.A mainboard providing power for servos and for a video system with switchable voltages, current measurement and general connectivity (6 full UARTs, I²C, 12 servo/motor outputs, 2 analog inputs, video input/output)

2.A processing board using a powerful STM32F765 at its core, boasting 1MB of flash memory, and 512KB of RAM capable of running the INAV, Ardupilot and Betaflight flight control software. It integrates an ICM20602 IMU, FrSky’s latest

graphic FrSky OSD

, and an SPL06 high precision barometer. An SPI bus connector allows for optional connection of a second vibration isolated IMU, which can be mounted to the board, or other peripherals. An SD card slot allows for data storage including BlackBox logging. It also includes a piezo audio transducer for system notifications and lost model locating.


Any FrSky receivers with a standard FPC interface can be connected directly to the processing board (RXSR-FC / R9MM-FC-OTA). All F.Port 2.0 Capable Receivers (Archer and Tandem Series Receivers, etc.), SBUS receivers, and some others with serial ports are also compatible.



Supports FrSky

F.Port 2.0


12 Servo/Motor Outputs & Multiple Serial Ports (6 UARTs, I²C, SPI)

Powerful STM32F765 Based Flight Controller is capable Running on INAV / Ardupilot / Betaflight Firmware


Graphic FrSky OSD

Supports FrSky S.Port Sensors

Built-in Multiple Sensors

Max 150A Capable Hall-effect Current Sensor

Built-in 3-axis Gyroscope & 3-axis Accelerometer Sensor (ICM20602IMU, ±2000dps, ±16g)

Supports ICM20601/ICM20602/MPU6000 IMU as external gyroscope module with vibration insulated box

Built-in Barometer sensor(SPL06-001)

Adjustable Voltage Output through integrated BEC function

Supports Black Box Data Record Function(via SD card)

Compatible Receiver

Standard FPC Interface on-board receiver with a perfect fit protection box (RXSR-FC/R9MM-FC-OTA, etc.)

All F.Port 2.0 Capable Receivers (Archer and Tandem Series Receivers, etc.)

SBUS Receivers and Some Others with Serial Ports



Dimension: 60*45*14mm (L*W*H)

Weight: 35g (Without connector)

Mounting(FC): 30.5*30.5mm with M3 grommets

Mounting(Rx): 13*13mm (R9MM-FC-OTA / RXSR-FC)

Battery Port: XT60 Plug

MCU: STM32F765VG (1MB Flash Memory, 512KB RAM)

IMU: ICM20602 (±2000dps, ±16g)

Barometer: SPL06-001

Graphic OSD:


Micro SD Slot

12* PWM Outputs

6* Full UARTs (Any UART can be configured to the S.Port via INAV)

1* I2C

2* Analog Inputs (0-3.3V)

1* Video Input

1* Video Output

1* Piezo Audio Transducer

2* ESC Power Pads

Voltage Range: DC 11.1V~51V (3S~12S Li-Po/Li-ion)

Current Sensor: Max 150A


Read more…


The 900MHz R9 MM-OTA receiver implements the ACCESS protocol and brings the user improved performance and features. The long range receiver supports wireless firmware updates over the air making binding to receivers even easier. As well as the convenience of checking the current receiver firmware version. The R9 MM’s compact form factor design is also carried over to the OTA version, and the R9 MM-OTA supports inverted S.Port as well.

This receiver works compatible with the new release R9M Lite Pro module,and the other 900MHz modules will also be supported when the ACCESS firmware is available.


Dimension: 16*10*2.8mm (L×W×H)

Weight: 0.7g (without antenna)

Number of Channels:

Non-LBT Version: 4/16CH (Telemetry)

LBT Version: 4/16CH (Telemetry) / 4/16CH (No Telemetry)

Operating Voltage Range: DC 3.5V – 10V

Operating Current: 100mA@5V

Operating Range: Up to 10km or above

Compatibility: R9M Lite/R9M/R9M 2019 with ACCST firmware

                            R9M Lite/R9M Lite Pro/R9M 2019 with ACCESS firmware


915MHz (Non-LBT Version)/ 868MHz (LBT Version)

Mini size and super lightweight

Supports OTA firmware update

Supports firmware version check

S.Port enabled and support telemetry data transmission

(Support F.Port, download firmware to support the function)

Inverted S.Port enabled

Low latency and high precision

With RSSI output in SBUS

Battery voltage detection supported

Detachable Ipex connector antenna

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This is going to be the 2nd Part of the Recommended Battery Series for FrSky Transmitter X9D Plus Transmitter. Don’t get confused with the title that FrSky X9D 2019 requires different batteries than x9d plus as you might think there are some changes in the battery compartment of it. But that is not the case. in fact, the battery compartment of X9d 2019 is exactly the same as of old Taranis X9d Plus. 

However, there is a special reason why this article is focused on Taranis X9D Plus 2019 rather than focusing on X9d plus in general. It is because X9D 2019 only supports operating voltage between 6.5v to 8.4v, which is basically a 2S lipo or Li-Ion. But, the older x9d plus (SE also) supports a wide range of operating voltage between 6 to 15V which means it can support even a 3s Lipo or Li-ion. 

FrSky Taranis X9D 2019 has also some other difference with older Taranis X9D when it comes to battery and charging. Older Taranis X9D plus has a Ni-Mh battery charging circuit that allows you to charge the stock battery with a charger that comes with it. Please note that the charging circuit is specifically for 6 cell Ni-Mh batteries and do not try to charge any other batteries like Li-Po or Li-ion in it. It is recommended to use the FrSky Ni-Mh with the charger if you are planning to charge the battery without actually removing the battery from the radio.

When it comes to X9D Plus, it only supports 2S batteries, and you might think about using the Ni-Mh battery with it. Of course, you can the Ni-MH battery in it. But don’t think to charge the battery using the transmitter, DON’T DO IT!!! FrSky X9D 2019 transmitter has a 2S lithium battery charging circuit in it that supports the charging through Mini USB Cable. 

That is specifically made for lithium batteries and above all, only for 2S batteries. Hence don’t charge the stock Ni-Mh battery using the supported USB charging in case you are going to use that battery in the New X9D 2019.  

Hence you can use the batteries that will fit in the Taranis X9D compartment for the FrSky X9D 2019 as well. In the last article, we have discussed FrSky Ni-MH 2000Mah battery, which is actually a good one. I still have a 4-year-old of that battery with me and it still performs well. So let's get our next candidate. 

3000mAh 2s X9D Li-Po

Check out this 3000mAh 2s Li-Po battery that you can find in amazon and Banggood is a great upgrade for the stock Ni-Mh 2000mah 7.2v battery. In Fact, this battery is specifically designed for FrSky X9D 2019 and other X9D radios as well.

When comparing it with stock Ni-Mh 2000mAh battery, this battery is 3000Mah 2 cell Li-Po. According to the theory, this battery should give you a 50% increased performance in battery life. But that is the only case if it got 3000mAh. However, this battery might disappoint you on that.

After running some tests to confirms the capacity, this battery is proved to be only around 2500mAh even though advertised as 3000mAh. Maybe the manufacturer is overstated it to attract buyers? Anyway, 2500mAh is still a good upgrade compared to the 2000mAh battery.

Usually, the capacity of Li-Po batteries is understated by the manufactures to compensate for any loss that might happen if they are stated as true which will basically give a good performance. So technically speaking, if you have a 1500mAh Lipo battery, the true capacity will be more than 1500mAh. It is usually around 50mAh extra for a 1500mAh Battery, So the battery will have an actual capacity of 1550mAh or 1600mAh.


Speaking of which, I thought this battery might be around 3100mAh or more, But I am disappointed in that point. Well, I am not disappointed with this battery, if that was the case then this battery won't has listed here. 2500mAh will give you a much better backup time than the stock battery. 

You can get around 6 hours of backup time with the stock Ni-Mh battery. With this 3000mAh battery, you can get around 10 hours of backup time which is indeed a worthy upgrade. When comes to the pricing, you will see it is pretty cheap. You can grab one from banggood or amazon for 15$ which is almost the same as of stock Ni-Mh battery.


How to Charge:

When it comes to charging, it is pretty easy and you don’t even need to take the battery out of it. How cool is that? FrSky X9D 2019 supports USB charging for 2S lithium-ion and polymer batteries. If the balance cable of the battery is plugged into the transmitter for powering it, you are all ready to go. Plugging the mini USB cable will charge it and you can use flawlessly.


If you are using it with the old Taranis X9D plus, then you will need to use a Balance charger for it. You can buy a JST to XT60 connector and charge it with the charger that you use to charge your regular Li-Po’s or Li-ion’s.



We have briefly discussed one of the popular but cheap alternative replacement battery for FrSky X9D. Well, it is not branded, but it will do the job. Hope this article has helped some to know about this replacement battery available for Taranis radio. In the next article, we will come up with another candidate. Stay Tuned!

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7386894065?profile=RESIZE_710xAll of the Archer receivers are hyper-matched with the ACCESS protocol. They not only feature wireless firmware upgrades, increased range, and telemetry performance, the R4 now supports more functions like configurable telemetry power, S.Port/F.Port switching and FLR output. Additional valuable features are under development to unlock the true potential of the ACCESS protocol.


ACCESS protocol with Over The Air (OTA)

Tiny and lightweight

Supports signal redundancy (SBUS In)

Full control range with telemetry

S.Port / F.Port

External battery / device voltage detection



Dimension: 30*17*6.2mm(L*W*H)

Weight: 3.8g

16/24 Configurable SBUS Channels

4 High-precision PWM Channels

Operating Voltage Range: 3.5 -10V

Operating Current: <60mA@5V

Control Range: Full range* with telemetry

(*Full Range: >2km, range may vary based on local conditions.)

Voltage Measurement Range via AIN2 (External device): 0-3.3V

Compatibility: All FrSky ACCESS transmitters

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What is FrSky Receiver PPM Output?

Let us take a look at what PWM & PPM is, along with FrSky Receiver PPM Output in this article. PWM or Pulse Width Modulation has been the de-facto choice for receiver out for decades and for good reason - it was direct, easy and simple to use. But as the need for more channels came necessary, it wasn’t logical to keep adding PWM channels, each taking an extra pin - enter PPM or Pulse Position Modulation which brings in multiple channels into a single pin.

What is an RC signal?

So, how do the servos on your RC plane or the rotors on your drones get the signal to move the rudder or control rod? Obviously from the receivers. So there must be a standard communication “talk” between the receiver and the servos, right? This is called as the RC signal. It is what enables servos or any peripherals such as Flight Controllers to understand what input the receiver is giving them.

What is a PWM signal?

The first generation of receivers used PWM or Pulse Width Modulation signal. So what exactly is a PWM signal?

A Pulse Width Modulation signal is a way of creating analogue signals from a digital source. Analogue signals are sinusoidal in nature while digital is in binary, ie. 0s and 1s. So to generate an analogue signal(continuously changing signal) from a digital source in a PWM signal, we change the frequency and duty cycle of the signal.

The duty cycle is the amount of time that the signal is HIGH (ON) versus the total time it takes to complete the cycle in terms of percentage. Frequency, on the other hand, is how fast one cycle is completed. For example, 100Hz (Hz or Hertz is the unit of frequency) means that the signal completes 100 cycles per second.

By combining duty cycle and frequency rates we can change how long a signal is in the HIGH state and how long the signal is in the LOW state. By varying these two values, you get an analogue signal (not pure analogue though)

So now that we have got that out of the way, let us talk about why PWM was widely used.

As previously mentioned, PWM just consists of two variables that is needed to be changed, which makes PWM signals extremely easy to be created and decoded by simple devices like your servo.

But as time passed by, pilots started to require additional channels for drones and auxiliary devices. Due to the hardware requirement of an additional PWM pin for each channel, it was quite obviously not feasible to have more than 6 to 8ch via separate PWM signal wires. Hence, there was a requirement to condense multiple channels into a single hardware signal wire.

This is where PPM came into play.

What is a PPM Signal & Why use it?

PPM or Pulse Position Modulation is another scheme used to send signals, but this has the added advantage of sending multiple channels/signals via a single PPM signal wire. How? Read on!

In PPM, each channel is lined up back to back on a single signal train (technically this is not how it works, but for simplicity, we will follow this schema). So, channel 1 is followed by channel 2 which is followed by channel 3 and so on. Once the final channel data is also sent (say channel 8), the pulse train goes back to the first channel and gets refreshed with new channel values.

So with this, we have essentially cut all the extra channel wires down to a single wire thus saving space, hardware pins and complexity of wiring.

So what are its downsides?

The issue is that standard servos do not support PPM signals but rather PWM only. This would not be a deal-breaker for the drone fliers out there but for planes and fixed wings, this could be an issue as they might not be using a flight controller which accepts PPM but rather directly connect receiver outputs to servos and ESCs.

Of course, you can get around by using a PPM to PWM converter module which is available quite cheaply.

Where does FrSky stand?

FrSky obviously has a vast number of receivers, each capable of outputting different types of data as PWM, PPM or the newer S.Bus. Few examples of FrSky Receiver PPM outputs are:





Among others.

In this article, we have seen what are radio receiver signals, what is PWM & PPM and the differences between the two and how FrSky Receiver PPM Output can help you save a lot of wires on your build and how clean the build is with PPM over PWM.


Read more…

What is the FrSky GPS Module?


In this article, we are going to cover some of the basics about the FrSky GPS Module and sensors. GPS that stands for Global Positioning System has gained its popularity from day to day life applications as well as many industrial applications. Moreover, it has rooted many applications in the Military sector where it is widely used. The applications of GPS is highly useful in RC hobby because of the same reason why it has gained popularity in day to day life.              

GPS can be highly useful in RC Hobby ranging from RC Airplanes from Drones or even RC Boats. It can be used to locate the precise location of Crafts if they are equipped with a GPS Receiver. If we know the precise location of our rigs at a specific time, it can be used to calculate some other highly useful data as well.

Having the Precise location of our RC craft can be used to retrieve it on the scenarios of crashes or failures. It can be used for autonomous flights or RTH (Return to Home) functions with the help of a Flight controller. Using the coordinates of the location at a specific time interval can be used to calculate the speed at which it is moving. Because speed follows the simple equation, distance divided by time.

When we know the coordinates of the location of our RC plane or other crafts with respect to the time, it is easy to calculate the speed at which it is moving with the simple equation. How cool it will be to know the speed of our rigs to have more excitement? I would really like it. That is how GoPro cameras (not all the GoPro cameras) are able to show the speed data on the videos as the camera has built-in GPS to calculate the speed.

GPS gives x,y,z (and time as well) coordinates which means it just not give the latitude and longitude but also the Altitude. Hence we can know the altitude without having the need for a Barometer sensor. In Short, We can get the location, speed, and altitude with the help of GPS of our RC Crafts. Let's cover more about the Frsky GPS module and sensors rather than talking about GPS and its uses.

FrSky GPS Module

Before getting to know about FrSky GPS Module, we need to understand the difference between a module and sensor in order to have a better understanding of the next section. A module is a part of a circuit or hardware (or software) that can be connected like auxiliary devices. But on the other hand, the sensor is more like a “raw module” which cannot be used like how you can directly use a Module.

The sensor is more like “PNP (Plug & Play)” where the module is more like “RTF (Ready to Fly)”. A module usually has extra circuits in it which makes it easier to use than a sensor where the wiring will need to be figured out.

FrSky GPS Module (or GPS-01) is a very old one released by FrSky. It was released before 2010 and that’s like more than 10 Years technology. I highly doubt if it exists today to purchase. This was supposed to use with the first prototype of telemetry released by FrSky. Smart port might be the first word to come to the mind when thinking about Frsky Telemetry.

But that wasn’t the case before 10 Years. There was no Smart Port telemetry and it required complex wiring to get Telemetry back in those days.  For Example, You will need a sensor hub in order to serve as an information collecting and processing center, monitor the model status, and feedback all data back to the receiver.          


FrSky GPS Module 01 is a small module and its output gives longitude, latitude and speed. The wiring is pretty simple as there is only three wires coming out of it. They are Ground, 5v, and Signal (RX) to be connected to the respective pins on the FrSky receiver that have telemetry. If you want to use other sensors like voltage, accelerometer, or even a temperature sensor, then you will need the sensor hub as they won't work in series.

FrSky GPS Sensor V2 

This is a more developed and advanced version of the FrSky GPS sensor that runs on Smart Port Telemetry. The wiring is pretty simple. You can connect it directly to the smart port of the receiver. Moreover, you don’t need a sensor hub to connect more sensors. Instead, You can connect the sensor in series without having a sensor hub.

This is supposed to be an introduction to the FrSky GPS Module and sensors. Hence we will cover this topic in detail in another article including how to use it.

We have briefly covered the Frsky GPS Module and sensors. The GPS Module (GSP 01) is a very outdated product and the chances are rare you might find it on sale somewhere. Above all, this stand-alone GPS are outdated, and more advanced functions can be performed with the help of a Flight Controller. 

FrSky GPS sensor V2 is a little bit advanced and easy to set up, but we cannot set any RTH functions with it. Hence it is more suited to go for a Flight Controller plus GPS Combo which might be cheaper than the GPS Module and can be used for autonomous flights as well.


Don’t worry, we haven’t stopped the FrSky GPS Module and sensor series here, We will be covering them in detail in the upcoming articles. Stay Tuned!

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Review: FrSky X8R Pro Receiver

We will look into the FrSky receiver and answer the question as to whether you should get one for your craft or project over any other receiver. We will also look into the feature list, compatibility and other such details of this receiver and compare it with the FrSky X8R Receiver as well from the previous article. 

Hardware & Pin Layout of the X8R Receiver

The FrSky X8R Pro is identical in every way to the X8R receiver, physically.The FrSky X8R Pro is a receiver that is mainly targetted towards planes and larger size quads or crafts where size is not a constraint and where you need pure PWM pins than S.Bus or PPM. The X8R has a plastic cover to protect it from the elements (which you can remove to save space and weight).

The X8R Pro outputs 8 individual PWM channels and also has an S.Bus port if you want to use with modern flight controllers like the PixHawk or micro quad flight controllers. The 8CH PWM is especially useful when you want to control a lot of servos and systems especially on planes and such systems where PWM is mainly used.


There is also a PWM RSSI output pin for getting Raw Signal Strength Indication for your Flight Controllers.

On the backside of the X8R Pro, there is a Smart Port pinout as well! This is great in case you want to connect external FrSky Sensors or provide telemetry data from your Flight Controller to your FrSky transmitter radio. It is weird that they have chosen to place the Smart Port pins at the antenna side of the receiver than on the right side where all the usual pins are situated; this will bring up an untidy wiring setup. 

Speaking of the antennas, the X8R Pro consists of 2 patch antennas(PCB antennas) instead of the normal dipole stranded wires. What does that have to do with the performance you may ask, quite simply, patch antennas provide more range than dipole antennas. In the case of the X8R, FrSky claims an additional 20% more range! So why not put patch antennas on all receivers? The reason is that patch antennas are highly directional with higher gain than traditional dipole antennas. Simply put, they receive signals very well in a particular direction ( parallel to the antenna orientation ) but have low signal strength in other directions.

This can be useful in some cases where the craft is moving parallel to the transmitter but once it changes its heading, it can lose some signal strength. In most cases, this wouldn’t make much of a difference, so you needn’t worry ;)

On the top side of the receiver, you will find the F/S (Bind) button as well as the two RED/GREEN indicator LEDs.

All the above-mentioned points are exactly as described for the FrSky X8R receiver. The only way to distinguish between the FrSky X8R and the FrSky X8R Pro is by checking for the “PRO” logo next to the R-X8R logo on the top of the receiver.


The R-X8R Pro from FrSky is an ACCST supporting receiver. We have already discussed ACCST & ACCESS in other posts, so we are not diving into that in this one.

The PWM as discussed is 8CH output and the S.Bus pinout would be perfect for stabilizers and flight controllers.

What differentiates between the R-X8R Pro and the X8R is that the FrSky X8R Pro version has higher precision and lower latency. Its deviation of PWM is reduced to 0.5us, and the delay of PWM output is 9ms less than that of the X8R in high-speed mode. A feature that deserves mention is the decreased effect of interference caused by the ignition process.

The Smart Port connector on both the X8R Pro also supports FrSky FBVS from with A2 port for simple voltage monitoring as well as other sensors and telemetry systems from FrSky like the TEMS-01 for temperature monitoring of your craft or engine etc. or another example would be the FSH-01 sensor hub, so you can connect multiple sensors to one board which then relays the data to the X8R Pro receivers for telemetry.

This feature is quite useful in helis and places especially the ones with a petrol or nitro engine where you have to monitor temperature and RPM along with other data.

You can use the S.Bus to output all 16CH from the receiver and in case you need to use 16CH PWM channels, you can get an S.Bus to PWM decoder which will translate the S.Bus signals into individual PWM channels for all your servos.

But that isn't all the FrSky X8R Pro receiver can do. It can also work in the D8 Mode to work with transmitter modules such as the DHT, DJT, DFT and DHT-U. In this mode, you have 8 channels and at the same time, you can use the Smart Port.


Dimension: 46.5mm x 27mm x 14.4mm

Weight: 16.8g

Operating Voltage Range: 4V-10.0V

Operating Current: 100mA@5V

Operating Range: >1.5km (Full Range)

RSSI output: analog voltage output (0~3.3V)

Firmware Upgradeable

Servo Frame Rate: 9ms (HS—High-Speed Mode)/18ms (FS—Normal Speed Mode)

All 16 channels require the FrSky Taranis or the XJT module.

For 8 channels in D8 Mode, you can use the FrSky Taranis or XJT, DJT, DFT, DHT and DHT-U modules.


The FrSky X8R Pro receiver is a great receiver for planes, helis and large drones where you need the full-range capabilities of the FrSky system and breaks out 8 channels of PWM and Smart Port connector with low-latency mode as well.

In the question, whether you need to buy this one, from my experience it is a great receiver with full-range capabilities but since the device runs on the ACCST protocol, I would personally resist from purchasing it, especially if you have the latest FrSky radios with ACCESS firmware. But from legacy builds and testing, this is a great receiver without a doubt!

Read more…

Long-range drones are increasingly present on the market, being used in military operations and agriculture, and the range of said drones is connected to its signal frequency, for example, a 900 MHz drone can reach a distance between 7 and 10 km. In general, the higher the frequency, the farther the drone can go. When operated in large centers that have interference from other frequencies, such as radio, TV, and cell phone, this distance can have a considerable drop. 

The combo with the FrSky 900MHz R9M 2019 transmitter module and FrSky R9 MX Long range receiver is the best on the market for building a 900 MHz drone. The quality of these products, pioneers in the industry, provides long-range and more efficient flights when compared to other modules and receivers.

Both the FrSky ACCESS R9M 2019 Long Range Module System and the FrSky R9 MX can be purchased at HorusRC’s online shop ( for just $29.99 and $19.99, respectively.

Transmitter Module

The FrSky 900MHz R9M 2019 consists of a module system with 4 RF power outputs, the R9M can also be used together with another receiver, which provides greater safety for the flight of your aircraft.

The different power output ports allow you to choose the ideal power for each flight situation. The RF power can be 10mW, 100mW, 500mW, and 1W, and at all levels, the use of telemetry is supported. An intelligent port is used for the transmission of telemetry data.


Long Range Transmitter Module FrSky R9M 2019 900MHz

Long-range, low latency, and high precision are the characteristics of the FrSky 900MHz R9M 2019. R9M's power supply is 6.5 ~ 13V. Modulations can be PXX or CPPM, being detected automatically. The R9M is compatible with all R9 series receivers. The frequency varies between 868 ~ 900 MHz. The operating range reaches 10 Km, perfect for the 900 MHz drone used on long distances.


Pin-in and Pin-Out overview of the R9M 2019.

The Smart Port (S. Port) present in the 900MHz R9M is a digital transmission interface developed especially by FrSky. In all products that contain Smart Port, user data from the serial port and other user input and output devices can be connected without limitations for numbers or sequences at high transmission speed, which is very important for a 900 MHz RC drone. 


The module works with 3 failsafe modes: No Pulse, Hold, and Custom. In the first mode, when a signal loss occurs, the receiver does not produce pulses on any channel. The Hold function consists of making the aircraft maintain its last position after the loss of signal (when the failsafe mode is activated). In custom mode, the aircraft will move to the predefined position after a signal loss.


The FrSky R9 MX, another product of great relevance for the construction of a 900 MHz drone, consists of an enhanced version of the other receivers in the R9 MM series, making it compatible with more external devices, providing an inverted S.Port output and supporting the use with other receivers. In addition, it has solder points to connect 4 PWM channels.


FrSky R9 MX.

The improved design proves to be more robust, compact, and durable and, together with synchronization with the latest ACCESS firmware, can be used to the true potential of ACCESS. The frequency varies between 868 ~ 915Mhz. Its dimension is 18 x 12 x 3.2mm and its weight is only 3.2g. The operating voltage is 3.5V ~ 10V and the operating current is 100mA at 5V. The R9 MX also supports OTA functions.

The MX differential for other FrSky receivers, in the SX and Stab line, is in the inverted S.Port output, signal redundancy, and super low latency. The range of control and telemetry can reach an impressive 10 km. The compatibility of the MX is confirmed with the receivers R9M Lite, R9M Lite Pro, and R9M 2019 with the firmware ACCESS. This receiver can be obtained together with the R9M module or individually at!

Final Considerations


Investment in these products is recommended. The combined use of the FrSky 900MHz R9M 2019 transmitter module with the FrSky R9 MX receiver will provide a safe, long-range flight and will bring an upgrade to your drone. The installation does not require any secrets and its use is very intuitive. These products stand out among others found on the market.

Quality technology, very well-developed features, and fail-safe are some of the benefits found in the FrSky 900MHz R9M 2019 transmitter module combo with the FrSky R9 MX receiver. If your goal is to build a 900 MHz drone for large ranges, these two items cannot be missing. FrSky is a brand of extreme quality and trust and its products can be found at!

Read more…

Essential RC Airplane Telemetry Technology


When trying to perfect their performance, RC hobbyists, pros, and even amateurs will frequently rely on RC Airplane Telemetry devices and systems, since a capable pilot should learn to better use his/her physical abilities and available technology, searching for ways to not only develop their own skills with practice but also to get as many as possible useful information about their vehicle’s behavior while flying.

With that in mind, one telemetry essential yet basic product that is highly recommended is the FrSky Smart Port RPM and Temperature Sensor. Like many other sensors from FrSky, this one also works with the Smart Port interface and, when installed properly in association with an S.Port enabled receiver, it can send the acquired data to its respective transmitter ‘s digital Telemetry Radio System.

Get yours now for just $18.20 at and improve the safety and performance of your flights!

FrSky Smart Port System

So… what is Smart Port? For those of you that don’t have a clue or never even heard about it in the first place: the S.Port (Smart Port) is a signal wire full-duplex digital transmission interface provided by FrSky Electronic Co., Ltd. and it was developed for the 2nd generation of FrSky systems.

Every S.Port enabled device - sound modules, display modules, sensors (such as the one we are talking about here), and any other device that works with a data interface that is in line with FrSky S.Port protocol - can be directly plugged in and arranged however the user desires, making RC components/device setup much easier than conventional multi-wire looms.

To sum it up, the Smart Port system offers this flexible and superior possibility of daisy-chaining several different components with high precision and without the need of a sensor-hub or other dataset. It is smaller, easier, and faster (approximately 6 times more than a conventional “hub system”), perfect for RC Airplane Telemetry.

RPM and Temperature Sensor

The FrSky Smart Port RPM and Temperature Sensor is a two-in-one telemetry device for RC Airplanes that can measure the RPM of brushless motors and also read the temperatures of other components besides the motor itself, such as ESCs and BECs, glow and gas engine cylinder heads, batteries, mufflers, voltage regulators, tailpipes and even ambient air!

Considering how important it is to know your RC airplane’s motor’s RPM and the temperature of critical components (for performance and safety reasons), the functions in the sensor will prove to be very useful. The RPM reading range (for a 2-pole brushless motor) is 1,000-30,000 rpm and the temperature can range from -20°C to 250°C (degrees Celsius) - 4°F - 482°F (degrees Fahrenheit).


One can notice in the image above that the sensor is small and lightweight (only 8g), which is ideal since it is a device that will not necessarily be used in every flight. 

Mounting and Setting up

As expected from a product made by FrSky, its users will find it straightforward and easy to install by following these steps:

Attach one end of the Temperature Sensor (TEMS-01) to your ESC and the other end to one of the two corresponding sets of pins (T1 or T2) that are mounted on the PCB (Printed Circuit Board).

Next, connect the sensor to any couple of wires from the brushless motor using the supplied JST connector.

Finally, connect the RPM sensor to the receiver (and/or other FrSky sensors) via Smart Port, then turn it on by linking your battery to the receiver.

Now to finish setting up:

Check the number of Pole Pairs in your brushless motor.

Enter Pole Pairs setting mode long-pressing the key until the Red LED is on.

Then, push the key repeatedly until you’ve got the correct number (in Binary) set on the little 4-digit display (0 to 3).

Power off the receiver after set.

Thus, as you can see, this entire installation and setup procedure is indeed quite simple and relies only on the push button and LED status indicator. For more detailed instructions and schematics, check the product manual on FrSky’s website.


Operation Specifics

Do bear in mind that this technology was designed to work with FrSky’s Smart Port interface, meaning that it is only compatible with Smart Port enabled receivers, such as the X8R, X6R, and X4R. Also, before using, please consider that although it can work with motor wires’ voltage range of 7.4 - 44.4V, that is, motors that run on 2S to 12S LiPo batteries, this sensor was made to operate at 4 -10V.


This RPM/temperature sensor can also be used simultaneously with other FrSky Smart Port enabled sensors, including the variometer, airspeed, GPS, lipo voltage, and current sensors, since all of those can daisy chain with each other through their Smart Port.

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