Humidity can be measured by various sensors, but sensors SHT from company Sensirion add many benefits moreover.
To be exact, a word „sensors“ is not a suitable expression in this case. As SHT series sensors contain on one chip humidity and temperature sensor, precise supply, low noise linear amplifier, AD converter and a serial interface, they represent a ready-made “device”. Moreover, they´re calibrated, thus to get an exact value it´s only necessary to read out data through a serial interface. In case of SHT2x series, it´s a standard, easy-to-implement I2C interface.
Sensirion sensors SHT2x series was more in detail introduced to you in our article „New sensors Sensirion will take you only 3x3mm on PCB!”, that´s why we´d like to bring you mainly few tips for simplification of development now.
Area of relative humidity and physics of water vapors is quite ample and into its introduction will initiate you the document Introduction_to_Relative_Humidity. Don´t be scared of many quotations, which you´ll find there – fortunately in common praxis we usually manage it with values of relative humidity and a dew point, which can be found together with code examples in Humidity_at_a_Glance.
As humidity sensors are very often used in residential places for regulation of heating and ventilation, also useful can be information about influence of humidity on a thermal comfort. For a practical usage of sensors it´s also important their placement on a PCB and a good access of air, what is in detail described in the document Sensirion_Humidity_Design_Guide. SHT2x are intended for 3VDC power supply, that´s why when using in 5V applications, you can face a problem of different voltage levels. This can be easily solved for example by a circuit described in the document SHT2x_5V_Supply_Embedding.
The program itself doesn´t need to be developed “from zero”. Examples can be found in the document SHT21_Sample_Code and SHT2x_Electronic_Identification_Code. Detailed information about testing and specification of SHT sensors can also be found in documents Sensirion_Humidity_Sensor_Specification_Statement and Sensirion_Humidity_Testing_Guide.
SHT25 – humidity and temperature precisely in every season – [Link]
Maxim’s Collection of temperature sensor and thermostat ICs
These temperature sensors offer good accuracy (±1.5°C) over the range of -25°C to +125°C and feature a 2-wire digital output with bus lockup protection and external reset.
Here is a small collection of circuits that provide an interface to sensor transducers including pressure, temperature, and others.
This circuit provides a highly integrated analog sensor signal conditioner targeted for automotive applications. The device provides amplification, calibration, and temperature compensation. Output is digital. Read the rest of this entry »
Epson has combined the reliability of quartz crystals with the tiny dimensions of MEMS devices to create a tiny high-resolution six degree-of-freedom inertial measurement unit that can track motion for everything from aerospace to oil-well drilling. [via]
Epson Downsizes Inertial Measurement Units - [Link]
Digital Temperature Sensor in TO-92 Package Ideal for Measuring Ambient Temperature.
The MAX31820 ambient temperature sensor provides 9-bit to 12-bit Celsius temperature measurements with ±0.5°C accuracy over a +10°C to +45°C temperature range. Over its entire -55°C to +125°C operating range, the device has ±2.0°C accuracy.
MAX31820 – 1-Wire Ambient Temperature Sensor - [Link]
New Tactile Sensor Is Lighter Than A Feather
Many researchers are focusing on flexible electronics, but the ones coming out of Someya-Sekitani Lab are the thinnest and most flexible circuits to date, the researchers say. (They have aptly nicknamed their work “imperceptible electronics.”) The sensors can conform to almost any 3-D shape. They’re also resilient, the research team says: the sensors maintain functionality up to 170 degrees C (though beyond 100 degrees C their efficiency gradually tapers off); they’re nearly unaffected when immersed in saline solutions; and they can be crumpled up, flattened back out, and even placed on rubber and stretched out–none of which drastically impacts performance.
New Tactile Sensor is Lighter Than a Feather - [Link]
janw @ instructables.com writes:
A few months ago, I saw an instructable by fjordcarver on how to build a coloursensor with an RGB led and an LDR. It inspired me to try whether I could improve his design.
Here are the things that I wanted:
The sensor should have as few pins as possible.
It should work as a stand-alone device. All calculations should be done on the device.
It should have a triggered mode and a continuous mode.
All parameters should be programmable.
Calibration parameters should be stored in the EEPROM of the microcontroller.
Firmware updates should be made possible
And finally: size does matter ⇒ The smaller the better.
I did choose an smd attiny85 as the brain of the sensor. It has a small footprint but a large enough flash for the calculations. It also has just enough pins for the project (all eight pins are used).instructables.com
Build your own (at)tiny colour sensor - [Link]
Research on graphene-based sensors at the Nanyang Technological University (NTU) in Singapore has yielded a new type of image sensor able to detect light over a broad spectrum, from the visible to mid-infrared, with very high sensitivity. In addition to being 1,000 times more sensitive to light than current low-cost imaging sensors used in compact cameras, it also uses 10 times less energy because it operates at a lower voltage. [via]
Graphene Photosensor is 1000x More Sensitive - [Link]
Infineon Technologies has released a family of 3D image sensor chips for touchless gesture recognition. Developed in cooperation with pmdtechnologies, the new chips are the first to combine a 3D image sensing pixel array with the digital conversion and control functions needed to develop very compact and accurate systems for gesture recognition applications in computers and consumer electronics devices. [via]
Image Sensor Recognizes Gestures - [Link]
Drawing only microamps (other than load current), this circuit switches in accordance with ambient light levels. Raju Baddi writes:
You can use an LED as a photoelectric sensor. A previous Design Idea shows that such a switch is highly power-efficient, consuming almost no power (Reference 1). However, you cannot adjust that configuration to switch at the desired light intensity. You can adjust the circuit in this Design Idea to any threshold level of light intensity necessary to maintain the on state of the photoelectric switch while retaining almost the same power efficiency of the original circuit
Adjust power-efficient LED switch to any light intensity – [Link]