Sensemotion

Week 1: Ring buffer in C

Scalar ring buffer in C: implement fixed-length ring buffer of double values supporting add_new, remove_oldest, and count operations:

typedef struct ring_buf ring_buf;
void add_new(ring_buf* rb, double val);
double remove_oldest(ring_buf* rb);
size_t count(ring_buf* rb);

Array ring buffer in C: implement fixed-length ring buffer of buffers of double values supporting add_new, remove_oldest, and count operations:

typedef struct ring_buf ring_buf;
void add_new(ring_buf* rb, double val);
double remove_oldest(ring_buf* rb);
size_t count(ring_buf* rb);

Week 2a: Audio programming with ALSA

Learn to output audio programatically using ALSA:

• Understand role of sample format (integer/floating point, signed/unsigned, bit depth, endianness), channel count, sample rate, buffer time, period time.
• Learn to list available audio output devices, list their parameters, and select them for audio output.
• MWE outputting an e.g. 440 Hz, 2-channel, 16-bit LE signed integer sine wave to a chosen audio output device.

Week 2b: Multithreaded processing; translation of modulation program to C

• Multithreaded producer/consumer use of ring buffer with system millisecond data stream: a producer thread continuously fills ring buffer, and a consumer thread continuously empties ring buffer, printing values to e.g. stdout or some other output stream.
• Translate full multithreaded data acquisition and sound modulation program from Python to C.
• Test modulation program in C with system clock’s millisecond data stream as modulating signal.

Week 3: Inertial Measurement Unit (IMU) data acquisition and processing

• Document wiring connections needed to stream IMU values from Raspberry Pi
• IMU data streaming: connect IMU to Raspberry Pi over I2C, stream ACC and GYRO values from IMU; print to stdout.
• Implement sound modulation program in C using e.g. magnitude of IMU ACC as modulating signal
• Repeat in stereo, e.g. using two ACC channels for stereo audio output.

Week 4: MC sensor data acquisition and processing MWE

• Document hardware and connections for reading values from potentiometer

• Read analog signal from e.g. a potentiometer using voltmeter

• Connect potentiometer to ADC; stream values from potentiometer and print to standard output

• Use potentiometer signal as modulating signal

• Document hardware and connections for reading values from MC sensor

• Read analog signal from MC sensor using voltmeter

• Connect MC sensor to ADC; stream values from MC sensor and print to standard output

• Use MC signal as modulating signal

Week 5: MC sensor with offset correction and amplification

• Document hardware and connections for connecting MC sensor to offset/amplifier chip
• Read analog output of offset/amplifier chip with voltmeter; compare to raw MC output.
• Connect offset/amplifier chip to ADC; stream values and print to standard output
• Use output of offset/amplifier chip as modulating signal