Special Sensor

This is an easy-to-program magnetic rotary position sensor with high-resolution 12-bit analog or PWM output. This contactless system measures the absolute angle of a diametric magnetized on-axis magnet. The project is designed for contactless potentiometer applications and its robust design eliminates the influence of any homogenous external stray magnetic fields.  The industry-standard I²C interface supports simple user programming of non-volatile parameters without requiring a dedicated programmer. By default, the output represents a range from 0 to 360 degrees.  It is also possible to define a smaller range to the output by programming a zero angle (start position) and a maximum angle (stop position). The AS5600 is also equipped with a smart low-power mode feature to automatically reduce power consumption. An input pin (DIR) selects the polarity of the output with regard to rotation direction. If DIR is connected to the ground, the output value increases with clockwise rotation. If DIR is connected to VDD, the output value increases with counterclockwise rotation.

This sensor board provides frequency output as per relative humidity value. The project is based on a unique capacitive cell, this relative humidity sensor is designed for high volume, cost-sensitive applications such as office automation, automotive cabin air control, home appliances, and industrial process control systems. It is also useful in all applications where humidity compensation is needed. The circuit is built using a low-cost NE555 timer as an astable generator, humidity sensor MK1 acts as a variable capacitor and is connected to the TRIG and THRES pin. Pin 7 is used as a short circuit pin for resistor R3. The HS1101LF equivalent capacitor is charged through R2, R3, and PR1 is set the threshold voltage (approximately 0.67Vcc) and discharged through R2 only to the trigger level (approximately 0.33Vcc) since R3 is shortened to the ground by pin 7. Since the charge and discharge of the sensor run through two different resistors, R2 and R3, the duty cycle is determined by the following formulas.

This project is the receiving end of a Wireless Humidity and Temperature monitoring system. The receiver unit is built around an Arduino microcontroller, utilizing the ATMEGA328 chip, which provides a reliable and efficient processing platform. The NRF24L01 transceiver module is used to receive data from the corresponding wireless sensor, while a 0.96-inch I2C OLED display is employed to show the received temperature and humidity values in real time.

This is a simple Proportional, Integral (PI) temperature control amplifier. A complete thermoelectric cooler (TEC) controller can be created using this PI amplifier and OPA569 Power Op-Amp or other output amplifiers such as DRV591, DRV592 and DRV593. Proportional-integrator compensation is simpler to adjust and often provides an adequate thermal transient response to the TEC driver amplifiers. The project consists INA330 chip and OPA2340 OPAMP.  The INA330 provides thermistor excitation and generates an output voltage proportional to the difference in resistances applied to the inputs. OPA2340 is used to create the PI closed Loop.

You may have seen many light-sensitive switch circuits based on an LDR sensor. Usually, the sensitivity of the LDR based light sensor is poor. We wanted a very sensitive light switch hence we decided to make a circuit based on a light sensor rather than LDR. After a little research on the internet, we found the OPT101 light sensor chip which includes a photodiode and a transimpedance amplifier in one package. The OPT101 light sensor provides an analog voltage output linearly proportional to light intensity.

This airflow sensor consists of INA326 precision instrument amplifier, double 100uA REF200 current sources, and a REF3025 2.5V reference voltage chip. Airflow dynamics dictate how much the voltage will increase or decrease for a given airflow rate. Therefore, the relationship between temperature and flow rate would have to be established for a method such as this to be useable. Two IN4148 diodes are used to sense the temperature, Diode D3 should be in static air and Diode D2 should be installed in the airpath flow path. The circuit works with 5V_DC and draws a few mA of current. REF3025 provides an accurate reference voltage which is 2.5V. Temperature linearity is within a tenth of a degree. The airflow is correlated to the change in D2 voltage. D2’s junction temperature and voltage are related to the airflow. D2 and D3 should be in the same temperature environment.

This is a simple signal conditioner circuit for Piezoelectric sensors. The circuit converts the input charge to voltage and the level shifts to the ADC input range of 0.1 V to 2.4 V. The circuit is built using AD8608 OPAMP from Analog devices. Piezoelectric elements are used to construct transducers for a vast number of different applications. Piezoelectric materials generate an electrical charge in response to mechanical movement, or vice versa, produce mechanical movement in response to electrical input. The board shown here is suitable for the Kistler type 8002K sensor. The K8002K is a high-precision accelerometer for shock and vibration measurements.

The module presented here is a sensor signal conditioner based on ZSC31010 CMOS integrated circuit, which enables easy and precise calibration of resistive bridge sensors via EEPROM programming. When mated to a resistive bridge sensor, it will digitally calibrate offset and gain with the option to calibrate offset and gain coefficients and linearity over temperature. A second-order compensation can be enabled for temperature coefficients of gain or offset or bridge linearity. ZSC31010 module communicates via IDT’s ZACwire serial interface to the host computer and it is easily mass-calibrated in a Windows environment. Once calibrated, the output signal pin can provide selectable 0 to 1 V absolute analog output; rail-to-rail ratiometric analog output; or digital serial output of bridge data with optional temperature data. U1 LM317 provides the 5V DC to the sensor chip. D1 is the power LED.

This is a new project, a single supply instrumentation amplifier with onboard bridge configuration, and a 2.5V precision reference voltage chip. The project can be configured for applications such as thermocouple amplifier, bridge amplifier, ECG amplifier, pressure sensors, medical instrumentation, portable instrumentation, RTD sensor amplifier. The project is based on INA333 micropower, zero drift, rail to rail out instrumentation amplifier chip. REF5025AID chip provides a precise 2.5V reference voltage. The board can be configured as an instrumentation amplifier or as a strain gauge amplifier with few easy changes.

The project presented here is an analog capacitive humidity sensor converter board suitable for various humidity measurement tasks. The circuit comes from Texas Instruments application note (see below). Most conventional capacitive proximity sensors produce a digital signal, but this circuit produces a DC output voltage that is a function of the relative humidity of the environment. The oscillator input for this circuit is a 1Khz sine source (1V_pp) feed to FQ input. The low frequency and sine characteristics keep RFI problems at a minimum. This sensor output converter may prove difficult to construct because of the small capacitances involved, parasitic capacitances in the sensor circuit, and noise pickup. The circuit requires an external 1Khz sinewave with 1V_pp signal and operates with a dual 15V DC supply.

This product offers a dual−channel low component count interface solution for ground-referenced variable reluctance sensors. Each of the two identical channels interfaces with a variable−reluctance sensor, and continuously compares the sensor output signal to a user−programmable internal reference. An alternating input signal of appropriate amplitude at IN1 or IN2 will result in a rectangular waveform at the corresponding OUT1 and OUT2 terminal, suitable for interface to either standard microprocessors or standard logic families. A diagnostic input, common to both channels, provides a means to test for degradation or loss of the physical connector to both sensors. Each channel of the circuit has independent input bias and clamp circuitry, and independent comparators with Hysteresis voltage generators. Both channels share a common reference generator for normal and diagnostic modes. Basically, the circuit converts the sinewave signal of the sensor into a clean rectangular wave signal.