[tps_title]IMU installation and operational testing[/tps_title]
The IMU module that has been chosen for this project is a 10DOF (10 degrees of freedom), a very complete one, equipped with the last generation digital sensors, that are high accuracy and low noise ones. As hinted before, it includes a gyroscope, an accelerometer and a magnetometer (with all the three axes) in addition to a high sensitivity barometer. In order to mount it please weld the male strip in the IMU module, being sure that the printed circuit board’s components points upwards, once installed into the board. Please insert the IMU module in the specific connector and make sure that the connection is excellent.
In order to be sure that the IMU module does not suffer from vibrations or that it may move, it is appropriate that it is fixed to the printed circuit board; please do not use metal elements but prefer plastic ones, such as for example some small nylon screws.
Since it is the heart of the stabilization, it is of the essential importance that the IMU module is perfectly operational and calibrated, otherwise your quadcopter won’t be able to fly, or anyway won’t be able to do it in a way that meets the expectations.
Among the files of the MultiWii project, you will also find the management software, that is essential for the quadcopter’s tuning; please go to the MultiWiiConf folder and execute the MultiWiiconf.exe file, taking care of choosing the one that is compatible with your operating system, before booting it please make sure that the board is connected to the PC by means of the corresponding USB/Serial converter.
At a first impression it may appear chaotic and complicated, but you will see that you will soon become familiar with its various functions. Up and on the left you will find the commands for the serial’s management and the buttons that will allow you to save and load a setup series. On the right you will find the sensors that have been detected on the board as highlighted as well as the board’s bearing, by means of graphic animations: the accelerometer (ACC), the barometer (BARO) and the magnetometer (MAG) are there, in addition – obviously – to the gyroscope, that is the only sensor that is absolutely necessary.
As you may see, the software supports even a GPS, a sonar and an optical sensor. Down and on the left you will find the sensors’ instant value; more on the right there is a diagram with the time trend of the same ones. Please calibrate the accelerometer (CALIB_ACC) and make sure that the board remained motionless, in a perfectly horizontal position. Please calibrate the magnetometer (CALIB_MAG) by rotating the board of 360° in every direction, for at least 30 seconds. Please keep the board in front of you, with the arrow pointed onwards; by rotating it towards right and towards left, the ROLL indicator will change accordingly. By inclining the board upwards and downwards the PITCH indicator will change accordingly.
In the initialization stage, a short flashing of the LED STATUS means that no kind of IMU is connected; a long flashing means that the IMU has been detected. After the initialization, the LED STATUS will prove to be turned on when the engines are armed, and turned off when the engines are unarmed. The LED ALARM will flash in the case an alarm condition has been found.
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Remote control’s activation
