System

The architecture flight controllers sensors can be summarised in the following diagram:

The required functionality of each of the sensors is described in further detail in the sensors sub-menu.

Software

This component is written using the C++ language.

Hardware 

The sensors provided by the Audronix system are:

• Magnetometers
• Accelerometers
• Gyros
• Pressure sensors (static and differential)
• Global positioning system (GPS)
• Temperature monitors
• Voltage Monitors
• Current Monitors
• Thermopiles

Each analog sensor is sampled by the analog to digital converter which is in turn sampled by the flight controller.

The sensors supported by the control system require 13 analog inputs, the LPC2138 processor core contains 4 analog to digital converters (ADC), of which two are unavailable due to their other functionality. The large number of analog inputs could be multiplexed into the available pins but this would require routing past the noisy digital signals on the main board and would still require at least one extra integrated circuit (IC). To resolve this problem a dedicated ADC IC was selected. The ADC chosen was the MAXIM, MAX1231. This IC is capable of sampling 16 inputs at a total of 300ksps. It has an internal reference temperature measurement which provides a means for temperature detection and correction. The chosen ADC has an accuracy of 12-bits which gives a resolution of approximately 0.730mV (3V / 4095). For the attitude reference from the magnetometers this means an ADC resolution of approximately 0.1 degrees which is adequate. The digital interface provided uses the SPI (Serial Peripheral Interface) protocol which uses in total six pins to talk to the processor. The SPI interface is desirable because it is implemented in hardware on the chosen processor, so therefore transparent to the users processor tasks.

Specifications: