The Reefwing AHRS library provides an Attitude and Heading Reference System (AHRS) class for use with Arduino compatible boards. The library has been tested with the Arduino Nano, Nano 33 BLE, Nano 33 BLE SENSE (REV 1 and REV 2), Nano 33 IoT, MKR Vidor 4000, Portenta H7 and the Seeed XIAO nRF52840 Sense boards.
An Attitude and Heading Reference System (AHRS) takes information from the Inertial Measurement Unit (IMU) and processes it to provide reliable roll, pitch and yaw angles.
We needed an instrument that can plot the voltage/thrust curve for any BLDC motor and propeller combination. We use Pulse Width Modulation to control the Electronic Speed Controller which drives the motor, and it would be nice to be able to relate the PWM percentage to thrust. Our first prototype used Force Sensing Resistors which will be compared to load cells. #arduino #fsr #dyno #shield
https://reefwing.medium.com/an-arduino-dc-motor-dynamometer-shield-part-1-54efd0c3e7e6
IMUs with 3 sensors each measuring 3-axes, pump out a lot of data. It can be difficult to work out how your IMU is performing, which is why the free open source data visualisation tool from x-io Technologies is so great. It is available for all major operating systems (Windows, macOS, and Linux). #arduino #imu #datavisualisation #datavisualization
Read all about it in our latest article on Medium:
In Part 1 we introduced our Arduino based ESC and followed this in Part 2 with an explanation of the power stage and MOSFET drivers. Part 3 focusses on the bootstrap capacitor which is part of the driver circuit used to turn the high-side MOSFET hard on. #arduino #bldcmotor #esc #bootstrapcapacitor #IR2110
https://reefwing.medium.com/an-arduino-nano-electronic-speed-controller-esc-part-3-e17392bd2887
We have been prototyping an Arduino based Electronic Speed Controller and planned to include a 0.96″ OLED display. Tests on an Arduino UNO, clocked at 16 MHz, have shown that this display could best be described as sluggish! Even using SPI, printing out 3 lines of text results in a loop cycle time of 15 Hz. Quelle horreur! This prompted us to investigate further to understand the bottlenecks, SPI vs I2C speed, and whether there were any work arounds. #arduino #oled #SSD1306 #DFR0650 #SPIvsI2C
https://reefwing.medium.com/oled-displays-are-slow-2f422840d735
Part 2 focuses on the power stage (AKA 3-phase bridge) and why MOSFET drivers are needed.
This series of articles was sponsored by PCBWay. #arduino #shield #ESC #bldcmotor #pcbway
https://medium.com/@reefwing/an-arduino-nano-electronic-speed-controller-esc-part-2-2bb5ec7c309a
Having delved into how BLDC motors operate and provided an overview of trapezoidal sensorless control, we can bring it all together in the design of an Arduino ESC shield. This turned out to be much harder than we expected – now we know why no-one does it!
This series of articles was sponsored by PCBWay.
#arduino #shield #ESC #bldcmotor
https://reefwing.medium.com/an-arduino-nano-electronic-speed-controller-esc-part-1-4f65076fb2e4
Controlling brushless DC (BLDC) motors is a lot harder than brushed, particularly if they don’t include a sensor for rotor position. This is why Electronic Speed Controllers (ESC’s) exist. In Part 11 of our series we demistify BLDC motors and their control.
https://reefwing.medium.com/how-to-write-your-own-flight-controller-software-part-11-dee7feef05f2
LiPo batteries are great for drones but you don’t want to over discharge them. To allow our Flight Controller to monitor battery capacity we used a non blocking scheduler and packaged our requirements up as an Arduino Library, NexgenTimer.
Our library is an amalgamation of the MillisTimer and ElapsedTimer libraries with some application specific examples and an extra Timeout class. It only uses functions from the Arduino core API and hence should work on all Arduino boards.
It can be downloaded using the Arduino Library Manager and you can read all about it in our latest article on Medium –
https://reefwing.medium.com/how-to-write-your-own-flight-controller-software-part-6-7ce0fa3e8008
The ESP32 is a dual core 32 bit microcontroller featuring WiFi and Bluetooth, and is able to be programmed with the Arduino IDE through an ESP32 add on. Note that not all libraries or functions that work with the ESP8266 or Arduino are yet functional on this new board.
It utilises the Xtensa® dual-core 32-bit LX6 microprocessor running at 240MHz, which is a step up from the ESP8266, while having similar power consumption.
The ESP32 ESP32 can also interface with other systems to provide Wi-Fi and Bluetooth functionality through its SPI / SDIO or I2C / UART interfaces. The ESP32 module comes preloaded with a ROM image of the AT command set, just like the ESP8266 did. If you want to waste 95% of this chip’s potential by using it as a glorified serial-to-WiFi modem, you are good to go!
If you are interested in IoT, I have released a number of new tutorials on using and programming the ESP-32, over on our sister site Reefwing Robotics.
The ESP32 makes for a great low power IoT sensor hub and is a more capable alternative to the Arduino. The caveat is that there is a bit more mucking around to get it to work. There is also some complexity in getting a dual-core micro controller to play along with a real-time operating system.
In addition to programming the ESP-32 in C, you can also use MicroPython. MicroPython is a complete development environment that runs on the ESP32 processor.
The tutorials available include: