Sensor category

The top 10 humidity sensors

Elizabeth Bustamante @ snapeda.com compiled a list the top 10 humidity sensors available today. Most of the sensors on the lists are from Honeywell, but surprisingly the top sensor comes from Sensirion. She writes:

Air humidity is an important factor to consider when designing an electronic device. Having too much humidity in the environment can cause condensation and corrosion, which can lead to anomalies in performance or even failures.

To prevent this, engineers use humidity sensors. These devices are used in systems deployed in humid environments, such as industrial control, instrumentation, climatology, and agriculture applications.

Most Accurate Digital Temperature Sensor STS35

Sensirion, a leading provider of environmental and flow sensor solutions, presents the STS35 temperature sensor – the most accurate sensor of the versatile STS3x series. The high-accuracy temperature sensor has been designed to fulfill the needs of demanding markets such as the medical and automotive sectors. Typical applications include body temperature measurement and temperature control.

The new STS35 temperature sensor is a high-end model in the STS3x series and has an outstanding temperature accuracy of DT = ± 0.1°C. Like all STS3x series models, the sensor features increased intelligence and reliability. Its functionality includes enhanced signal processing, two distinctive and user-selectable I2C addresses and communication speeds of up to 1 MHz. The DFN package can be integrated into an extensive variety of applications thanks to its footprint of 2.5 x 2.5 x 0.9 mm3 and the wide supply voltage range of 2.4 V to 5.5 V. Furthermore, the STS35 sensor includes a configurable alert function, allowing it to be used as a temperature watchdog. Like all sensors by Sensirion, the STS3x is based on the unique CMOSens® Technology that integrates the sensing element and read-out electronics onto a single chip, enabling high production volume at an exceptional price/performance ratio.

Four-Channel Thermometer on OLED display

David Johnson-Davies @ technoblogy.com build a four-channel thermometer that monitors the temperature at four temperature sensors, and gives a continuous readout on a small 128×32 OLED display. It’s a useful project for various applications like PSU or PC monitoring. The article describes 1-wire and code in details.

It could be used in any application where you want to monitor multiple temperatures, such as in controlling a greenhouse, checking the output transistors in a power amplifier, monitoring key points in an overclocked gaming PC, monitoring the chips on a Raspberry Pi, or checking the temperature in different rooms in a home.

Four-Channel Thermometer on OLED display – [Link]

TSL2540 Ambient Light Sensor matches eye-response

TSL2540: Other Product Document (English)

ams (Graz, Austria) has posted details of the TSL2540, a very-high sensitivity light-to-digital converter. Evaluation kit is available:

The TSL2540 is a very-high sensitivity light-to-digital converter that approximates the human eye response to light intensity under varying lighting conditions and transforms this light intensity to a digital signal output capable through a 1.8V I²C interface. The ALS sensor features 2 output channels, a visible channel and an IR channel. The visible channel has a photodiode with a photopic Interferometric UV and IR blocking filter and the IR channel has a photodiode with an IR pass filter.

TSL2540 Ambient Light Sensor matches eye-response – [Link]

Bosch BME280 sensor combines pressure, humidity and temperature measurement

Bosch Sensortec announces a world first in sensor technology: the BME280 Integrated Environmental Unit combines sensors for pressure, humidity and temperature in a single package. This unique sensor has been developed to support a broad range of emerging high performance applications such as indoor navigation, home automation control, personalized weather stations and innovative sport and fitness applications. The precise altitude measurement function of the BME280 is a key requirement in applications such as indoor navigation with floor tracking where exceptional accuracy, low temperature drift and high resolution are needed. Additionally, the BME280 has a best-in-class response time of just one second for humidity determination, excellent ambient temperature measurement and low energy consumption.

More precise measurement at lowest power consumption

With a small footprint of just 2.5 x 2.5 mm2and a height of 0.93 mm in a space-saving 8-pin LGA package, the sensor offers high design flexibility and is ideally suited for mobile devices with limited space such as smartphones, tablets, smart watches and electronic wristbands. Very low current consumption of only 3.6 µA (at 1 Hz) makes the BME280 Integrated Environmental Unit particularly suitable for battery-driven applications. Three power modes and separately configurable oversampling rates for pressure and temperature measurements allow designers to adapt the BME280 to a wide range of use cases.

The humidity sensor within the Integrated Environmental Unit measures relative humidity (0% to 100%) across a wide temperature range from -40°C to +85°C with a fast response time of less than 1 second. The humidity measurement accuracy is ±3% with a hysteresis of 2% or better, and the temperature reading accuracy is within 0.5°C.

more details on the Bosch Press Release.

Sensor board for micro:bit

The MonkMakes Sensor Board for micro:bit allows you to sense sound level, temperature and light level.

Features

  • 3V and GND connections can be made from either side and allow you to power a second board such as the MonkMakes Relay Board or MonkMakes Speaker.
  • LED ‘power on’ indicator
  • Reverse polarity protection
  • All three sensors are analog and can be connected to pins P0, P1 and P2 using alligator clips.

Sensor board for micro:bit – [Link]

SprintIR6S, World’s Fastest NDIR CO2 Sensor

Gas Sensing Solutions (GSS) Ltd is a designer and manufacturer of low power, high speed Non-Dispersive Infrared (NDIR) carbon dioxide gas sensors. Recently, it has claimed a new speed record for its SprintIR6S NDIR CO2 sensor.

The new sensor comes with response rates that had never been reached before by any other NDIR CO2 sensors. It can take up to 20 readings per second, and has a six-times faster response rate than the current SprintIR.

According to Ralph Weir, GSS’ CEO, the sensor uses LEDs and photodiodes to measure differential light absorption between light at 4.2 and 4.4 μm. So, they succeeded to develop ultra-speed sensor, while other detectors take several seconds or even minutes to take a reading.

“Our LEDs, by contrast, are Solid State emitters, and illuminate almost instantly. With the new SprintIR6S, we’ve also minimised the sample volume down to only 2ml, which enables us to achieve our fastest ever response rates.”
~ Ralph Weir

The SprintIR6S is less than a cubic inch in dimension with 23.8mm in diameter and 24mm tall. It operates at a range between 3.25V and 5.5V and consumes only 35mW. SprintIR6S is also available in measurements ranges from 0% to 100%.

Main Specifications of SprintIR6S

  • Warm-up Time: < 30 seconds
  • Operating Conditions:
    • 0°C to 50°C (Standard)
    • 0 to 95% RH, non-condensing
  • Recommended Storage: -30°C to +70°C
  • Sensing Method:
    • Non-dispersive infrared (NDIR) absorption
    • Patented Gold-plated optics
    • Solid-state source and detector
  • Sample Method: Flow through
  • Measurement Range: 0-5%, 0-20%, 0-100%
  • Accuracy: ±70 ppm +/- 5% of reading (100% Range ±300 ppm +/-5% of reading)
  • Non Linearity: < 1% of FS
  • Pressure Dependence: 0.13% of reading per mm Hg in normal atmospheric conditions
  • Operating Pressure Range: Atmospheric pressure range. Lower and higher pressures require more advanced pressure compensation.
  • Response Time: Flow Rate Dependent – see graph below. Response time also depends on user configurable digital filter settings.
  • Power Input:
    • 3.25 to 5.5V. (3.3V recommended).
    • Peak Current 33mA.
    • Average Current <12mA.

Applications of SprintIR6S are those which require capture of rapidly changing CO2 concentrations. Such as capnography, fitness testing, metabolic assessment, sports science, veterinary medicine, bio-medical, and incubators.

For more information and detailed specification, you can download the datasheet, or contact GSS to order or for more information.

backscatter-system

Researchers Develop Long Range Backscatter Sensors That Consume Almost No Power

Researchers at the University of Washington developed a new backscatter sensors that can operate over long ranges with very little power. The researchers demonstrated for the first time that the device runs on almost zero power and can transmit data across distances of up to 2.8 kilometers.

The long-range backscatter system developed by UW researchers
The long-range backscatter system developed by UW researchers

Backscatter communication works by emitting a radio signal and then monitoring the reflections of that signal from sensors. As the transmitter generates the signal, the sensors themselves require very little power. But this kind of system badly suffers from noise. Noise can be added anywhere – on the transmitter side, on the channel or on the sensor array. The key to solving this problem is a new type of signal modulation called chirp spread spectrum.

By using the chirp spread spectrum modulation technique, the team was able to transmit data up to 2.8 kilometers while the sensors themselves consumed only a few microwatts of power. Such extremely low power consumption lets them run by harvested ambient energy and very small printed batteries. The cost is surprisingly cheap too. The sensors would cost just 10 to 20 cents per unit if bulk purchased.

Today’s flexible electronics and other sensors need to operate with very low power typically can’t communicate with other devices more than a few feet or meters away. By contrast, the University of Washinton’s long-range backscatter system achieved pretty strong coverage throughout a 4800-square-foot house, an office area including 41 rooms, and a one-acre vegetable farm at extremely low power and low cost.

Shyam Gollakota, the lead faculty and associate professor in the Paul G. Allen School of Computer Science & Engineering, said,

Until now, devices that can communicate over long distances have consumed a lot of power. The tradeoff in a low-power device that consumes microwatts of power is that its communication range is short. Now we’ve shown that we can offer both, which will be pretty game-changing for a lot of different industries and applications.

These low-power sensors have endless potential applications. They can be used for everything from wearable health monitors to scientific data collection devices. Though there are no confirmed products yet, the team has created few prototypes in the form of flexible sensors worn on the skin, smart contact lenses, and more.

LiDAR board is only 25x21x8mm

Dinesh Bhatia @ indiegogo.com writes:

tinyLiDAR provides Arduino users simplified access to cutting-edge smartphone-technology. Don’t pull your hair out! Now you can use ST’s latest Time-of-Flight sensor easily with tinyLiDAR. Its the low cost “easy button” of distance sensors. We’ve put all the smarts inside our onboard 32-bit micro so you won’t have to dedicate your Arduino to the task. Ultra-fast, fully-featured, accurate, low power and low cost – what more could you ask for?

LiDAR board is only 25x21x8mm – [Link]

Digital Compass

This project uses SmartEverything Development Board’s on-board iNEMO 9-axis intertial module to make a digital compass. by 4D Makers @ hackster.io:

The Digital Compass project uses the SmartEverything Development Board’s on-board iNEMO 9-axis inertial module specifically the 3D Magnetometer. The magnetometer module is sampled for the x and y axis readings and then computed its compass headings.

The project is partnered with the gen4-uLCD-24DT to graphically display a rotating compass, and accurately represent the compass heading.

Digital Compass – [Link]