The October issue features articles on topics ranging from FAT cache to IIR digital filters to a quadcopter that uses a mechanical gyro. Let’s review.
Jeff’s quadcopter uses a mechanical gyro that is “an inexpensive yet elegant attempt to counteract wind gusts.” With its protective shield removed, you can see the motorized spinning rotor that sustains equilibrium as its frame moves.
On page 16, Stuart Oliver details how to use math routines that include the dsPIC hardware features, such as the accumulators and barrel shifter. He uses the math for implementing Assembler routines.
Turn to page 30 to learn how Kerry Imming uses FAT cache for SD card access. You can implement his cache technique in a variety of other applications.
Before you start a new project, familiarize yourself George Novacek’s tips on managing project risk (p. 34). He explains how to define, evaluate, and handle risk. Better yet, why not just reduce risk by avoiding as many problems as possible?
Bob Japenga addresses this issue as well (p. 38). In the third part of his series on concurrency in embedded systems, he details how to avoid concurrency-related problems, which can be difficult because the more concurrency you add to a project, the more complicated it becomes.
Ed Nisley presented a MOSFET tester in his August 2012 article, “MOSFET Channel Resistance.” In this issue, Ed covers temperature measurement, the control circuitry, the firmware’s proportional integral control loop, and more (p. 42).
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A fan under the black CPU heatsink keeps it near ambient temperature, so that the Peltier module under the aluminum block can control the MOSFET temperature. The gray epoxy block holds a linearized thermistor circuit connected to the Arduino microcontroller under the PCB. (Source: E. Nisley)
Check out Robert Lacoste’s article on page 58 for an introduction to IIR digital filters. You’ll learn about the differences between IIR filters, FIR filters, and analog filters.
WinFilter allows you to calculate and simulate all kind of IIR filters just by entering their key characteristics (left). The plots shows you the resulting frequency and time behavior. (Source: R. Lacoste)
Working with an unstable mechanical gyro? As Jeff Bachiochi explains, a MEMS system is the solution (p. 68).
Lastly, check out the interview with Helen Li on page 54. You’ll find her impressive research exciting and inspirational.
Circuit Cellar's editorial team comprises professional engineers, technical editors, and digital media specialists. You can reach the Editorial Department at editorial@circuitcellar.com, @circuitcellar, and facebook.com/circuitcellar
