Accelerometers and gyroscopes are used for various safety features in modern vehicles.Possible appliance of such sensor is very wide, from crash detection for airbag release to electronic stability control systems, allowing the car to aid the driver during evasive maneuvers at speed. Gyroscopes can also be used with navigation systems to provide fine location information and help when there is no GPS signal, e.g. in tunnels. We used this sensor in
Mobile devices have accelerometers and gyroscopes used for screen orientation detection and enhanced navigation. Computer game consoles are using handsets with accelerometers and gyroscopes to enhance game play.One such sensor that we have used is parallax LISY300 Gyroscope Module.
The LISY300 Gyroscope Module is a single-axis yaw rate sensor providing up to 300°/s full scale rotation detection at up to 88 Hz. Useful in balancing robots or auto-pilot systems, the LISY300 Gyroscope Module can detect how many degrees it has turned on its planar axis allowing the host microcontroller to
stabilize the platform and correct for drift.
± 300°/s full scale
Easy SPI interface
Small DIP form factor module
Compatible with most microcontrollers
Power requirements: 3.4 VDC to 6.5 VDC (5 VDC recommended) @ 5.25 mA
Communication: SPI (4 MHz max)
Operating temperature: 32°F to 158°F (0°C to 70°C)
Dimensions: 0.75” L x 0.69” W x 0.47” H (19.18mm L x 17.56mm W x 11.95mm H)
R/C Helicopter stabilization
Auto-pilot system for R/C Planes
Interface with microcontroller is very simple using SPI. Pinout and PCB layout is given on picture below
And pin out is:
Theory of Operation
Internally the LISY300AL Gyroscope generates approximately 1.6V on its analog output when it is still.This value is affected very little by temperature so compensation is not required. The output of the LISY300AL is fed into a National Semiconductor ADC101S021 10-bit ADC. This ADC has a high-speed (4 MHz) SPI interface and the signal pins can operate at 3.3V and 5V. Both the gyroscope and the ADC are
internally regulated to 3.3V.
As the gyroscope is rotated clockwise (looking down at the top of the IC) around its z-axis the analog output voltage falls. As the gyroscope is rotated counter-clockwise around the z-axis the analog output voltage rises. The amount of change in the voltage is relative to the speed in which the gyroscope is rotating. By measuring the output voltage the rate of rotation can be determined.
The static (non-moving) analog output of the gyroscope can be affected by the manufacturing process, therefore it is necessary to calibrate the gyroscope before use. This can be done at startup by making sure the gyroscope is still and sampling the ADC several times to get the average value. This value can be obtained each time at startup or could be stored after initial calibration.
The LISY300 Gyroscope has a sensitivity of 3.3 mV/°/s. The ADC is 10-bits providing approximately 3.22 mV per step. Each step is approximately 1 degree of change on the gyroscope. Communication Protocol The communication with the Gyroscope actually takes place with the ADC, not the gyroscope chip itself.The ADC has an ADC capable of up to 4MHz communication speed, however the gyroscope will only update at a rate of 88 Hz. Communication with the ADC is initiated by bringing /CS low and clocking 16 bits via the SPI bus. Communication is terminated by bringing /CS high again. The data is sent MSB first and is preceded by 3 leading zero bits and trailed by 2 zero bits. These are most important information that you will need when making your project. For more detailed technical information use parallax LISY300 Gyroscope Module datasheet and LISY300AL gyroscope sensor datasheet.
You can find complete project with source code available for this sensor use in article Rotating office chair angular position and rotation speed measurement using gyroscope and ATmega16.