Inertial navigation peripheral/Sensors

This section will cover the main hardware needed for the peripheral to function, the sensors, micro controller and XO connection.

Hardware choice

Sensors

Our choice of sensors was primarily dictated by cost. We needed at least two sensors, a gyroscope to measure angular velocity, and an accelerometer for tangential acceleration. Initially we were planning to have pitch and roll compensation for the device, but this was shoved towards the end.

For the accelerometer, we got a Triple Axis Accelerometer Breakout - ADXL330 from Sparkfun for $34.95 and for the gyroscope, we got a Gyro Breakout Board - Dual Axis IDG300 for $74.95, also from Sparkfun. Hypothetically, we could get cheaper sensors in the future, as we only ended up using one axis of the gyroscope and accelerometer.

Microcontroller

We used a PIC 18F4550 as the heart of our peripheral. This was a slightly excessive choice, as we could have used the PIC 18F2455 as well, which would shave off some cost. Both uCs have built in USB modules, which minimizes the number of components needed in the peripheral.

Like most PIC uCs, they have built-in analog to digital converters which are used to convert the analog signals from the sensors into integers.