Its been a few years since I built a Tricopter based on an Arduino controller. Recently a friend asked about using a Multicopter on a farm for checking out orchard trees so thought it would be a good excuse to put a Quadcopter together.
The Quadcopter is based on the same Arduino MultiWii controller as before, but this one has an electronic compass (magnetometer) and pressure sensor (barometer) for control of heading and height as well as the usual gyro and accelerometer (auto level).
The controller and frame were purchased from Ebay, an X525 frame and Crius flight controller board. Four 900kV motors and four 20Amp speed controllers interface to the controller. The whole thing went together pretty well with the exception of the gyro not working initially. This was traced down to bad soldering on the flight controller board gyro chip (ITG3205).
The flight controller came with version 1.9 MultiWii software loaded, but the current version is 2.1, so 2.1 was downloaded and compiled with the Arduino package and downloaded to the copter via the usb interface on the flight controller board.
Before version 2.1 was compiled the config.h settings were changed to the Crius SE controller and Xcopter mode chosen.
The MultiWii flight controller is configured using MultiWiiConfig software. This software comprehensively monitors and configures the flight parameters.
The default PID values were used as a starting point. The autolevel (accelerometer) was assigned to the gear channel.
After a thorough test of the flight controller reliability after the soldering touchups, the transmitter was configured for channel 1 collective, channel 2 roll, channel 3 pitch and channel 4 yaw. The transmitter uses open source ER9x software and is configured using companion 9x which is a PC based transmitter configurator. Channel 5 (gear) is used for autolevel. At this point, heading lock and altitude lock are not configured and will be done later after the quad is tuned.
Power was applied to the quad, the transmitter turned on and the quad armed by holding the throttle switch hard right. The motors spun up to idle as expected. A test holding it over my head verified that the gyros were controlling the motors in response to roll/pitch and yaw as expected. I was just thinking how careful you have to be around these things when my finger made contact with an idling prop. A quick rush inside for a bandaid or two and came back some time later for a test fly.
It flew well and was quite stable with default parameters.