Coming Attractions

PC Fan Control
To enable all fans inside a PC to be controlled in safe and flexible ways, a circuit was designed that provides extensive capabilities. It allows up to six PWM fans to be controlled simultaneously, with the rotation speed of each fan measured individually by reading its tacho signal. An existing fan control on the PC motherboard (like the CPU cooler) can be used as a signal source for controlling the fans connected. The circuit can operate autonomously when configured using USB, but it’s also possible to control and monitor it via USB.

Software Defined Radio with AVRs
Next month we kick off a new series showing how Atmel AVR microprocessors can be used for digital signal processing (DSP). A total of three circuits board gets proposed. The first includes a signal generator based on an ATtiny2313, the second board contains a complete SDR receiver with display and serial interface, and the third PCB is used to construct an active antenna. In total, more than 20 experiments can be done with these boards. All software was created with the WINAVR GCC Compiler in AVR Studio, and of course it’s available on the Elektor website for your own experiments.

LED Touch Panel
Today, almost every cellphone or tablet computer has a touchscreen. There are several ways to implement a touch screen, ranging from a resistor array with a plastic film using a capacitive grid etched on to the screen, right up to a camera device that tracks your finger movements. However, there are other touch screens with a configuration you wouldn’t think of straight away. This article describes a touch screen for home or lab construction, with an 8 x 8 matrix of LEDs determining the presence of your finger by alternately transmitting and receiving and so determine which LED is covered by the finger.
 

Elektor UK/European March 2012 edition: on sale February 16, 2012.

Elektor USA March 2012 edition: published February 13, 2012.