MPXM2010GS 0 To 10kPa (0 To 1.45 PSI) Pressure Sensor Module

The MPXM2010GS silicon piezoresistive pressure sensors provide accurate and linear voltage output directly proportional to applied pressure. These sensors house a single monolithic silicon die with strain gauge and thin film resistor network integrated. The sensor is laser trimmed for precise span, offset calibration and temperature compensation. The series includes a strain gauge and thin-film resistor network integrated on each chip

 

Features

  • Temperature Compensated over 0 to +85 C
  • 0 To 10kPa (0 to 1.45psi)
  • Output 25mV Full Scale
  • Supply 10V DC (10-16V Possible)

Applications

  • Respiratory Diagnostics
  • Air Movement Control
  • Controllers
  • Pressure Switching

This Details is from NXP Application AN1950

The resolution of the system is determined by the mm of water represented by each A/D count. As calculated above the system has a span of 226 counts to represent water level up to and including 40cm. Therefore, the resolution is:

Resolution=mm of water/Total # counts=400mm/127 counts=3.1 mm per A/D count

 

Bellow Schematic from NXP Application Note

Reflective Object Sensor- Infra Red Optical Proximity Switch Using PLL LM567

Reflective Object Sensor- Optical Proximity Switch Using PLL LM567

The simple circuit is based on LM567 PLL IC and optical sensor QRD1114 from Fairchild semiconductor. The QRD11114 reflective sensor consists of an infrared emitting diode and an NPN silicon photo Darlington mounted side by side in a black plastic housing. The on-axis radiation of the emitter and the on-axis response of the detector are both perpendicular to the face of the QRD1113/14. The photo Darlington responds to radiation emitted from the diode only when a reflective object or surface is in the field of view of the detector.

  • Supply 5V DC
  • Output LED
  • Output TTL 5V
  • Sensing Distance Up to 15MM
  • Sensing Distance Adjustable

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Dual-Channel Quadrature Hall-Effect Bipolar Switch Module For Magnetic Encoder for Motion Control application.

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Dual-Channel Quadrature Hall-Effect Bipolar Switch Module For  Magnetic Encoder for Motion Control application.

The A1230 is a dual-channel, bipolar switch with two Hall-effect sensing elements, each providing a separate digital output for speed and direction signal processing capability. The Hall elements are photolithographically aligned to better than 1 µm. Maintaining accurate mechanical location between the two active Hall elements eliminates the major manufacturing hurdle encountered in fine-pitch detection applications. The A1230 is a highly sensitive, temperature stable magnetic sensing device ideal for use in ring magnet based, speed and direction systems located in harsh automotive and industrial environments.

Featutrs

  • It Provides Dual A & B Channel Like optical Encoder
  • Simple Module help to make Magnetic Encoder for Motion Control application
  • Supply 5V DC
  • TTL Output
  • Two matched Hall-effect switches on a single substrate
  • 1 mm Hall element spacing
  • Superior temperature stability and industry-leading jitter performance through use of advanced   chopper stabilization topology
  • Integrated LDO regulator provides 3.3 V operation
  • Integrated ESD protection from outputs and VCC to ground
  • High-sensitivity switch points
  • Robust structure for EMC protection
  • Solid-state reliability
  • Reverse-battery protection on supply and both output pins

Applications

  • Brushless DC Motor Rotation
  • Speed Sensing
  • Pulse Counter
  • Magnetic Encoders

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The A1230 monolithic integrated circuit (IC) contains two independent Hall-effect bipolar switches located 1 mm apart. The digital outputs are out of phase so that the outputs are in quadrature when interfaced with the proper ring magnet design. This allows easy processing of speed and direction signals. Extremely low-drift amplifiers guarantee symmetry between the switches to maintain signal quadrature. The Allegro patented, high-frequency chopper-stabilization technique cancels offsets in each channel providing stable operation over the full specified temperature and voltage ranges.

Additionally, the high-frequency chopping circuits allow an increased analog signal-to-noise ratio at the input of the digital comparators internal to the IC. As a result, the A1230 achieves industry-leading digital output jitter performance that is critical in high performance motor commutation applications. An on-chip low dropout (LDO) regulator allows the use of this device over a wide operating voltage range. Post-assembly factory programming at Allegro provides sensitive switch points that are symmetrical between the two switches.

Bipolar Switch Applications and Working from Allegro Micro
There are four general categories of Hall-effect IC devices that provide a digital output: unipolar switches, bipolar switches, omnipolar switches, and latches. Bipolar switches are described in this application note. Similar application notes on unipolar switches, omnipolar switches, and latches are provided on the Allegro™ website.

Bipolar sensor ICs are designed to be sensitive switches. (Note that the term “bipolar” refers to magnetic polarities, and is not related to bipolar semiconductor chip structures.) A bipolar switch has consistent hysteresis, but individual units have switchpoints that occur in either relatively more positive or more negative ranges. These devices find application where closely-spaced, alternating north and south poles are used, resulting in minimal required magnetic signal amplitude, ΔB, because the alternation of magnetic field polarity ensures switching, and the consistent hysteresis ensures periodicity.

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Applications for detecting the position of a rotating shaft, such as in a brushless dc motor (BLDC) are shown in figure 1. The multiple magnets are incorporated into a simple structure referred to as a “ring magnet,” which incorporates alternating zones of opposing magnetic polarity. The IC package adjacent to each ring magnet is the Hall bipolar switch device. When the shaft rotates, the magnetic zones are moved past the Hall device. The device is subjected to the nearest magnetic field and is turned-on when a south field is opposite, and turned-off when a north field is opposite. Note that the branded face of the device is toward the ring magnet.

 

 

Dual-axis accelerometers with signal conditioned voltage outputs Using ADXL203 Circuit & PCB Layout

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The ADXL203 is high precision, low power, complete dual-axis accelerometers with signal conditioned voltage outputs, all on a single, monolithic IC. The ADXL203 measure acceleration with a full-scale range of ±1.7 g, ±5 g, or ±18 g. The ADXL203 can measure both dynamic acceleration (for example, vibration) and static acceleration (for example, gravity).

The typical noise floor is 110 μg/√Hz, allowing signals below 1 mg (0.06° of inclination) to be resolved in tilt sensing applications using narrow bandwidths (<60 Hz).

The user selects the bandwidth of the accelerometer using Capacitor CX and Capacitor CY at the XOUT and YOUT pins. Bandwidths of 0.5 Hz to 2.5 kHz can be selected to suit the application.

 

FEATURES

  • High performance, dual-axis accelerometer on a single IC chip
  • 5 mm × 5 mm × 2 mm LCC package
  • 1 mg resolution at 60 Hz
  • Low power: 700 μA at VS = 5 V (typical)
  • High zero g bias stability
  • High sensitivity accuracy
  • −40°C to +125°C temperature range
  • X and Y axes aligned to within 0.1° (typical)
  • Bandwidth adjustment with a single capacitor
  • Single-supply operation
  • 3500 g shock survival
  • Qualified for automotive applications

 

APPLICATIONS

  • Vehicle dynamic controls
  • Electronic chassis controls
  • Platform stabilization/leveling
  • Navigation
  • Alarms and motion detectors
  • High accuracy, 2-axis tilt sensing
  • Vibration monitoring and compensation
  • Abuse event detection

 

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THEORY OF OPERATION

The ADXL203 are complete acceleration measurement systems on a single, monolithic IC. The is a single-axis accelerometer, and the ADXL203 is a dual-axis accelerometer. Both parts contain a polysilicon surface-micro-machined sensor and signal conditioning circuitry to implement an open-loop acceleration measurement architecture. The output signals are analog voltages that are proportional to acceleration. The ADXL203 are capable of measuring both positive and negative accelerations from ±1.7 g to at least ±18 g. The accelerometer can measure static acceleration forces, such as gravity, allowing it to be used as a tilt sensor. The sensor is a surface-micromachined polysilicon structure built on top of the silicon wafer. Polysilicon springs suspend the structure over the surface of the wafer and provide a resistance against acceleration forces. Deflection of the structure is measured using a differential capacitor that consists of independent fixed plates and plates attached to the moving mass. The fixed plates are driven by 180° out-of-phase square waves. Acceleration deflects the beam and unbalances the differential capacitor, resulting in an output square wave whose amplitude is proportional to acceleration. Phase-sensitive demodulation techniques are then used to rectify the signal and determine the direction of the acceleration.

The output of the demodulator is amplified and brought off-chip through a 32 kΩ resistor. At this point, the user can set the signal bandwidth of the device by adding a capacitor. This filtering improves measurement resolution and helps prevent aliasing. PERFORMANCE Rather than using additional temperature compensation circuitry, innovative design techniques have been used to ensure that high performance is built in. As a result, there is essentially no quantization error or nonmonotonic behavior, and temperature hysteresis is very low (typically less than 10 mg over the −40°C to +125°C temperature range). Figure 11 shows the 0 g output performance of eight parts (x and y axes) over a −40°C to +125°C temperature range. Figure 13 demonstrates the typical sensitivity shift over temperature for VS = 5 V. Sensitivity stability is optimized for VS = 5 V but is still very good over the specified range; it is typically better than ±1% over temperature at VS = 3 V.

SETTING THE BANDWIDTH USING CX AND CY

The ADXL203 has provisions for band limiting the XOUT and YOUT pins. Capacitors must be added at these pins to implement low-pass filtering for antialiasing and noise reduction. The equation for the 3 dB bandwidth is

f–3 dB = 1/(2π(32 kΩ) × C(X, Y))

or more simply,

f–3 dB = 5 μF/C(X, Y)

The tolerance of the internal resistor (RFILT) can vary typically as much as ±25% of its nominal value (32 kΩ); thus, the bandwidth varies accordingly. A minimum capacitance of 2000 pF for CX and CY is required in all cases.

Table 7. Filter Capacitor Selection, CX and CY

Bandwidth (Hz)

Capacitor (μF)

Adaptive Variable Reluctance Sensor Amplifier Using LM1815

The LM1815 is an adaptive sense amplifier and default gating circuit for motor control applications. The sense amplifier provides a one-shot pulse output whose leading edge coincides with the negative-going zero crossing of a ground referenced input signal such as from a variable reluctance magnetic pick-up coil.

In normal operation, this timing reference signal is processed (delayed) externally and returned to the LM1815. A Logic input is then able to select either the timing reference or the processed signal for transmission to the output driver stage.

The adaptive sense amplifier operates with a positive-going threshold which is derived by peak detecting the incoming signal and dividing this down. Thus the input hysteresis varies with input signal amplitude. This enables the circuit to sense in situations where the high speed noise is greater than the low speed signal amplitude. Minimum input signal is 150mVP-P.

Adaptive Hysteresis
Supply 12V

Application

Position Sensing With Nothch Wheel
Zero Crossing Switch
Motor Speed Controller
Tachometer

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