Dalprop FOLD F5 folding 5-inch propellers

Foldable propellers are nothing new. We use them on RC airplanes and consumer-ready drones like DJI Mavic for years. But they were never available for 5-inch mini quads! Until now that is, since just today I got a package from Foxeer with 2 (2 and a half) sets of brand new Dalprop FOLD 5.1″ folding propellers for multirotor FPV drones! Yay…

DALprop FOLD F5 foldable 5-inch propellers

DALprop FOLD F5 foldable 5-inch propellers

What to say… They fold indeed. My props are pre-production samples and came not assembled! Double the fun with some puzzles!

DALprop FOLD F5 foldable 5-inch propellers

DALprop FOLD F5 foldable 5-inch propellers

DALprop FOLD F5 foldable 5-inch propellers

Unfortunately, I can not yet test them. It’s raining and the weather forecast says it will be raining for 2 more days. But after that, nothing will stop me from testing them on my favorite flying spot!

STM32 F1, F3, F4, G4, F7 and H7 flight controllers

STM32 F1, F3, F4, G4, F7 and H7 flight controllers

Currently, almost all flight controllers we use on our multirotor FPV drones and airplanes are powered by microcontrollers from an STM32 family. When we say about flight controller families or generations, we refer to them by the family of the MCU. For example:

F1 flight controllers are no longer supported

or

You should get F7 to do it

STM32F1

Historically speaking, F1 were the first flight controller boards for MultiWii derivatives based on STM32 MCU. All the F1 boards like Naze32 or CC3D (ok, this one is from OpenPilot family) were equipped with STM32F103 chips. Currently, F1 boards are not supported by any major flight controller firmware. Reasons are simple: low speed, lack of hardware floating-point acceleration, very little RAM and Flash memory, only a couple of UARTs. They were not powerful enough and as a result, had to die.

Do not buy and if you have one, just keep it somewhere in a drawer as a souvenir of good old times. Read More

Betaflight 4.2

Betaflight 4.2 Gyro, Looptime and Gyro Stage 2 Lowpass Filter

Betaflight 4.2 brings some very important changes to how various tasks are processed. Especially how gyro,m filtering and PID loop are working together.

First of all, the gyro is sampled always at the gyro native speed. This means, MPU6000 will be sampled at 8kHz. Always. At the same time, PID and filtering are working as a separate task at 8kHz, 4kHz, 2kHz and so on. Depending on user configuration and MCU processing speed.

5-inch mini quad with Betaflight 4.2

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Betaflight 4.2

Betaflight 4.2 – new features and most important changes

It’s been a while since we had the last release of Betalight. After all, Betaflight 4.1 was released in October 2019. Half a year ago. Luckily, developers were not hibernating over the winter, and brand new, 4.2, release is scheduled for May 2020. Slightly more than 2 weeks from now.

Below is the list of the most important (from my perspective) functional changes.

The most important changes:

  • By default, Betaflight 4.2 sets DISABLED ESC protocol and it is up to the user to set correct protocol supported by ESCs
  • Virtual Current Meter uses now throttle setpoint, not RC command. Now it will work correctly with throttle limiting, throttle boost and so on. It should give more reliable current estimation now
  • Support for FrSky Graphical OSD aka Pixel OSD
  • By default, stick arming is disabled in Betaflight 4.2. It can be changed with enable_stick_arming CLI command
  • Improved STM32H7 support
  • Added the STM32G4 support. We can expect boards based on STAM32G4 to appear in the future
  • Dynamic Notch Filter improvements – it is now faster and more reliable
  • NFE Race Mode implementation known from Silverware
  • Yaw Spin Recovery auto mode
  • Scheduler improvements – gyro processing works always with full gyro sampling rate while filtering is run together with the main PID loop. It results is a more reliable scheduling and less jitter
  • Quick Rates System – max rotation rate is set in degrees per second and curve is set with the expo. This is very similar to rates used by INAV
  • For Crossfire CRSF it is now possible to display SNR in dB instead of RSSI dBm in OSD

Other change:

  • D_min and FF improvements
  • disarm reason is now logged in the Blackbox log
  • ICM42605 gyro and accelerometer sensor support
  • Dynamic LPF curves are now configurable
  • RC channels preview was added to the OSD
  • CLI name command removed
  • OSD distance from home alarm
  • CMS VTX management improvements
  • More GPS options are now settable from Betaflight Configurator
  • SOFTSPI feature removed
  • support for Redpine protocol for CC2500 RF chipsets
  • serial passthrough via MSP
the best rc radio transmitters

The best RC radio transmitters for Q2 2020

The last year was a good year in terms of new radio transmitters. It’s no longer a choice between FlySky and FrSky. We have new players and new products. Below is my, very subjective, overview of the most interesting radios on the market.

Still the best – FrSky X10S Horus

FrSky X10s Horus

In my very personal opinion, FrSky X10S Horus is the best option out there. Some might argue that the shape is not the best, or gimbals are not in the “perfect” place. Perhaps. On the other hand, I do not find those things an issue and I use my X10S for 2 years now. Amazing gimbals, good layout, great LCD and ergonomics. If I would have to find a real-life problem with the Horus, it would be a small battery. You really have to charge it after every trip to the airfield. Besides that, perfect! Read More

Espressif ESP32

ESP8266, ESP32 and ESP32-S2 comparison

Currently, there are 2 types of MCU from Espressif on the market: ESP8266 from 2014, ESP32 from 2016 and ESP32-S2 that debuted in the second half of 2019. Although ESP32-S2 is not yet very popular, it is expected it will replace ESP8266 as a cheaper, more powerful and more secure alternative in the upcoming years.

The table below compares the main features of ESP8266, ESP32 and ESP32-S2

ESP8266 ESP32 ESP32-S2
MCU Xtensa L106 Xtensa LX6 Xtensa LX7
Number of cores 1 2 1
Number of bits 32 32 32
Clock frequency 80MHz 160MHz 240MHz
Coprocessor No Yes Yes (RISC-V)
WiFi 802.11 b/g/n 802.11 b/g/n 802.11 b/g/n
Bluetooth No BT 4.2 BR/EDR & BLE No
RAM 160kB 520kB 320KB
Internal flash No ESP32‑D2WD Only – 2MB No
External SPIFlash Up to 16MB Up to 16MB Up to 1GB
GPIO 17 36 43
SPI 2 4 4
I2C 1 (software) 2 2
I2S 2 2 1
UART 2 3 2
ADC 1 18 20
ADC resolution 10-bit 12-bit 12-bit
DAC No 2 2
DAC resolution 8-bit 8-bit
Software PWM 8 16 8
SDMMC interface No Yes No
Temperature sensor No Yes Yes
Touch sensors No Yes Yes
CAN No 1 No
Ethernet MAC No 1 No
inav sensors

All the INAV sensors: are they required or optional?

INAV can use various sensors to fly drones and airplanes: gyroscopes, accelerometer, magnetometers, barometers, GPS, OpFlow, rangefinders, and airspeed. Some of them required some are recommended and some are a purely optional piece of hardware.

Here is the full list:

INAV Sensors:

Gyroscope and accelerometer

Required. The flight controller will not boot without a gyroscope and accelerometer. They are usually 2-in-1 devices (MPU6000, MPU6500, etc) that contain gyroscope and accelerometer in one package. Read More

Espressif ESP32

Espressif ESP32-S2

When Espressif release ESP32 WiFi & Bluetooth capable MCUs back in 2016, many things changed in the DIY and tinkerers community. We finally had a cheap MCU that could do real IoT stuff and was easy to use. However, the cheap ESP32 is not really cheap in relative terms. Sure, it is cheap, but there are cheaper solutions. ESP8266 for example.

Yes, the old ESP8266 that lacks any built-in security and which power consumption is not that low even in a deep sleep mode. It was expected that Espressif would, sooner or later, offer an improved replacement for ESP8266. Cheaper than ESP32, but with features that ESP8266 lacked. Read More