Sunday, June 21, 2009

Analog Devices ADXL series Accelerometers

The Analog Devices ADXL series of Accelerometers are an amazing set of devices. As an example, the ADXL325 is a small, low power, complete 3-axis accelerometer with signal conditioned voltage outputs. The product measures acceleration with a minimum full-scale range of ±5 g. It can measure the static acceleration of gravity in tilt sensing applications, as well as dynamic acceleration resulting from motion, shock, or vibration.

The user selects the bandwidth of the accelerometer using the CX, CY, and CZ capacitors at the XOUT, YOUT, and ZOUT pins. Bandwidths can be selected to suit the application, with a range of 0.5 Hz to 1600 Hz for X and Y axes, and a range of 0.5 Hz to 550 Hz for the Z axis. The ADXL325 is available in a small, low profile, 4 mm × 4 mm × 1.45 mm, 16-lead, plastic lead frame chip scale package (LFCSP_LQ).

Functional Block Diagram:

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Saturday, June 13, 2009

LM386 Low Voltage Audio Power Amplifier

The LM386 is a power amplifier designed for use in low voltage consumer applications. The gain is internally set to 20 to keep external part count low, but the addition of an external resistor and capacitor between pins 1 and 8 will increase the gain to any value from 20 to 200.
The inputs are ground referenced while the output automatically biases to one-half the supply voltage. The quiescent power drain is only 24 milliwatts when operating from a 6 volt supply, making the LM386 ideal for battery operation.

Typical low part count application:


To make the LM386 a more versatile amplifier, two pins (1 and 8) are provided for gain control. With pins 1 and 8 open the 1.35 kW resistor sets the gain at 20 (26 dB). If a capacitor is put from pin 1 to 8, bypassing the 1.35 kW resistor, the gain will go up to 200 (46 dB). If a resistor is placed in series with the capacitor, the gain can be set to any value from 20 to 200. Gain control can also be done by capacitively coupling a resistor (or FET) from pin 1 to ground.

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Wednesday, June 3, 2009

Digi XBee X-CTU Manual and Utility

If you use Digi XBee modules for wireless communication, the Digi X-CTU application is a must. X-CTU is a Windows-based application provided by Digi. This program was designed to interact with the firmware files found on Digi’s RF products and to provide a simple-to-use graphical user interface to them. X-CTU is designed to function with all Windows-based computers running Microsoft Windows 98 SE and above. X-CTU can either be downloaded from Digi’s Web site or an installation CD.

The Digi X-CTU Datasheet can be downloaded here.

The Digi X-CTU application can be downloaded from Digi here.

X-CTU Screenshot:

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