SensorLab

-- BobVitale? - 14 Apr 2006

Sensor Lab for CMPE126/126L
Table of Contents


Prof Tao's list of Equipment for CE163L?

For the initial offering of the the lab section of 163 will require the following equipment:
3 sets with each include
  • PC platform with NI Labview installed
  • Data Acquisition Device (minilab 1008 or better)
  • PowerDrive? DS3658
  • Connector Blocks
  • Phototransistor LTR-3208E and IR LED
  • PZT Stack Actuator
  • Accelerometer

Lab 2 needs

Hi, Bob,

Our first lab on LabView? went well. For the second lab, we will work on IR-LEDs and photo transistors. The parts we will need in each set include (see below)

-Hai

Item status
NI DAQ 6009 card Installed in lab
power supply 5V should have lab power supplies
1 prototyping board BELS can issue
resistors: 1M x 1, 1k x 1 BELS should have in stock
phototransistor - LTR-3208E need to order
IR LED: forward voltage drop of about 1.6-2 V Need to order
wires BELS has in stock

DAQ Device

Status - 3 boards order from National Instruments, model USB- SOERT-22907 suggested --- miniLAB™ 1008, USB-based DAQ device with 8 channels of 12-bit analog input, two analog outputs and 28 DIO bits

Spoke with National Instruments field engineer. She recommended that if we are working with acceleratometers, we might look at DAQ devices that provide higher resolution and bandwidth thatn the minilab1008. Also iepe type acceleratometers require excitation and signal conditioning. A suggestion USB-based DAQ was the USB-9201. Cost is quite high.

Here is a quote from National Instruments. * ni-DAQ-quote.pdf: NI DAQ Quote

PowerDrive? DS3658

Connector Blocks

Phototransistor LTR-3208E and IR LED

Now listed as BELS Part Number: 1984

PhotoTransistor? LTR-3208E
Mouser Electronics
http://www.mouser.com/index.cfm?handler=displayproduct&lstdispproductid=814003&e_categoryid=445&e_pcodeid=85900

Do we need to match the transistor and LED??

Some potential IR LEDs. Not sure of the amount of illumnination needed. The 3208E becomes saturated at Ee= 1mW/cm2. Does that mean the transistor turns on with that amount of illumniation. If so then the OP290 series LED is needed over the OP166 series.

PZT Stack Actuator

Accelerometer

Hi, Bob, Analog Device's ADXL 150 seems to be a good choice. -Hai
Specifications & Data on the Analog Device ADXL150:

Specs:
  • ±50g single axis accelerometer with analog output.
  • ADXL150 employs an open-loop architecture. With zero average dc voltage on the beam, the excitation square waves can swing to the power supply rails, with the beam biased at one half the supply voltage. The larger amplitude of the 100-kHz excitation in the ADXL150 results in reduced sensitivity to electronic device noise and is a contributing factor to its improved noise performance.
  • The ADXL150 has a 2-pole gain-of-3 Bessel low-pass filter on board [the ADXL250­see below­includes a 2-pole filter for each channel]. These filters can be used to prevent aliasing of high-frequency components in the demodulator output with A/D converter clock frequencies in associated data-acquisition circuitry. A second input to the filter is connected to a resistive divider with a gain of 1/6, brought out to a package pin. It provides a convenient offset adjustment point for the accelerometer, with a net gain of +0.5 for the applied voltage.

Because extensive use is made of CMOS logic, and the open-loop architecture allows simpler signal conditioning circuitry, the device draws only 1.8 mA of supply current at 5V (including the 2-pole output filter), a >80% reduction from the ADXL50.

The increased excitation levels used, along with carefully executed chopper modulation/demodulation techniques, yield a noise density of just 1mg/Hz, less than 1/6 that of the ADXL50. The improved dynamic range enables the ADXL150 to be used in applications such as machine health, vibration monitoring, shock sensing, and instrumentation.

The ADXL150 has a sensitivity of 38mV/g, measured at the output pin. The full scale range is ±50 g, for a total signal swing of 3.8 V, with a single 5-V supply. This significant output voltage range allows the designer to take full advantage of the input range of a single-supply A/D converter, such as might be found in a microprocessor system.

* The ADXL150 is a complete sensor on a chip. Just connect a single 5-V power supply (with clean output, bypassed to ground by a decent-quality ceramic capacitor) and connect the output to its readout destination.

If the self-test pin is left open-circuited, an internal pulldown resistor ensures normal operation. With nothing connected to the offset adjust pin, the output voltage is unmodified.

To adjust the output zero-g voltage level, use the offset adjust pin. The offset can be adjusted by applying an analog dc voltage, including the supply voltage or ground. Computer control can be achieved in various ways, e.g., by a serial or parallel D/A converter, or by a modulated duty cycle with an R-C averager. A choice of three offset adjustment values can be achieved with a three-state digital output bit and a series resistor.

iMEMS® Accelerometers Web Site: http://www.analog.com/imems/

http://www.analog.com/UploadedFiles/Technical_Articles/3088350815599120474accel.pdf#xml=http://search.analog.com/search/pdfPainter.aspx?url=http://www.analog.com/UploadedFiles/Technical_Articles/3088350815599120474accel.pdf&fterm=ADXL150&fterm=ADXL150&la=en http://www.analog.com/library/analogDialogue/archives/30-4/acccel.html


Accelerometer - Questions & Commentary

-- BobVitale? - 18 Apr 2006 email was sent to Prof Tao about accelerometer. The closest p/n avail seems to be a gyro evaluation board. ADXRS150EB?
The ADXRS150 is a 150 deg./sec. angular rate sensor (gyroscope) on a single chip, complete with all of the required electronics. The sensor is built using Analog Devices' proprietary iMEMS® surface micromachining process

Analog Devices responsed to email: Good Afternoon,

The part is not on the system, I would imagine that it must be obsolete, however, I don't see anything that is giving any information on it. I would suggest that you contact our applications engineers to see what to use in it's place. The number is: 1-800-262-5643, #1 on the menu.

Sincerely, Judy Wholey Analog Devices Customer Service Buy on Line

-- BobVitale? - 14 Apr 2006 Sent questions about where to get the ADLX150 to the AD web site. In reviewing Analog Devices web site, I cannot find where the ADXL150 is available as a current supported part. They talk about it some but it does not appear in the current parts listing. I'm wondering if the ADXL150 has been superceeded by something else. Email sent to Prof Tao concerning