In short, I need to create a device that can take some real-time distance and motion measurements. Ideally, this device will be small, inexpensive, simple to setup/install, and wireless (which means wireless communication and wireless power). To start, though, I'm just getting a functional prototype going for proof-of-concept, so I'm not worried about the size, wired vs wireless aspect, etc.
It's Alive!
Maybe I'll get a chance to go into some more detail at a later date, but for now I'll skip to the cool part: version 0.2 is operational! (I arbitrarily used v0.1 to getting the accelerometer working, and v0.2 has the distance sensor as well).
Device v0.2: RaspberryPi + GY-521 MPU-6050 accel/gyro + HC-SR04 range sensor
Since I went into this pretty blind (no idea what I'm doing at the outset) and a with low expectations (circuits was one of my worse courses in physics undergrad), I made some choices that erred on flexibility. For one, I started with a Raspberry Pi B+ model. Choosing a RasPi instead of an Arduino came down to two key differences: 1) RasPi is an all-in-one computer while Arduino is a much simpler microcontroller, so the former has a lot more functionality while the latter is intended for a single or fewer uses; and 2) Arduino's programming environment is in C, while Raspberry Pi runs a parred-down Linux, so I can code in just about anything I like: Python, Perl, Java, C, etc.
There are a wealth of helpful tutorials for getting started in RasPi and interfacing it with various sensors & equipment. For the accelerometer/gyroscope unit, I used a Kootek GY-521 MPU-6050 (also bought a couple ADXL-345 units which were popular on blogs & tutorials). And for distance, I'm used an HC-SR04 ultrasonic range sensor. I'll make a note to come back at a later time and link out to the best tutorials I found, but a simple Google search gives you plenty.
Oh, and for the Raspberry Pi board itself, I went with a starter kit from CanaKit, which provided a lot of the important peripherals in addition to the basic RasPi board (e.g. power supply, wifi dongle, enclosure). As a complete idiot when it comes to DIY circuits/electronics, I can say the CanaKit package was a really great place to start.
In the end I'm actually a bit surprised that once I learned the basics of build-it-yourself electronics, the hardware aspect of my project was a surprisingly small portion of the hours I've put into it so far. So I'm already going back to the coding stuff I love! My next task is to start learning multi-threading & queuing in Python, so I can have the two sensors running in parallel and controlled by a single program.
