Bitwise operations are mathematical transformations applied to binary numbers. Binary numbers are written in base two, which means that they are composed of a string of zeroes and ones. The numbers that most people are familiar with are written in base ten, which means that there are ten digits with each digit indicating a number of powers of ten: Continue reading
One of the first NerdKits projects involves programming a temperature sensor, not unlike the one that comes built in to the Sprite. The temperature sensor in the NerdKit looks very much like a transistor, but in this case the left pin connects to the voltage and the right pin connects to ground. The middle pin outputs analogue measurements corresponding to the amount of heat in its environment. In order to use this data, the microcontroller unit must first convert it into digital information.
The analogue-to-digital conversion executes according to the C program that I write, with help from the NerdKits libraries. At the highest level, the MCU executes the following
main function: Continue reading
The USB NerdKit is an introduction to microcontrollers package offered by NerdKits.com. Rather than being an integrated development platform like the TI Launchpad or the Arduino, the NerdKit is composed of modular components and is designed to teach newcomers the fundamentals of embedded systems. In other words, it’s a perfect place to start learning about MCU programming.
This last Wednesday, December 7 was a big day for the Southern Illinois University Edwardsville physics department. Dr. Neil deGrasse Tyson visited the campus through a joint effort between the university’s Arts & Issues program, an annual lecture series that has been part of campus life for over 25 years, and the Shaw lecture series, a biennial presentation focusing on special topics in physics.
While the final hardware specifications of the Sprite are still in flux, the microcontroller unit that will serve as the spacecraft’s brain has been more or less set. Meet the TI MSP430.
The MSP430 is branded as an “Ultra-Low Power” processor capable of interacting with analog signals, sensors, and digital components. It’s a 16-bit chip, like the CPU in the SNES (or, if you Nintendidn’t, the Sega Genesis). Of course, if all goes as planned the Sprite won’t be playing Earthbound; it will be sending radio signals from orbit.
The Kickstarter project‘s funding period has closed successfully, which means that I (and over 100 others) have a little Sputnik destined for the sky. Twenty-six of those backers will be programming their Sprites before liftoff, myself included.
Some of the backers are individuals like myself, but others – such as the British Interplanetary Society and Kidz in Space – have designated their Sprites to be part of a fleet. Being part of a Sprite fleet adds an extra dimension to the endeavor because it opens the possibility of networked communication between the spacecraft. I’m looking forward to seeing how these groups decide to use their fleets.
The Cornell team spent the last couple of months improving the prototype design. The Sprites now carry more efficient solar cells. Additionally, a shortlist of on-board sensor candidates is being assembled. A basic Sprite contains only one sensor, a temperature sensor built in to its microcontroller unit (MCU). Adding a three-axis magnetometer or a gyroscope to the spacecraft would significantly extend its capabilities, making the information it sends back to Earth via radio transmissions more dynamic. The challenge lies in finding sensors that can be powered by the solar cells and are small enough to fit on the board.
So it’s official – this project is now in motion. Ladies and gentlemen, we have left stardock!