The Si7005 is a digital relative humidity and temperature sensor from Silicon Labs. It integrates fully factory-calibrated humidity and temperature sensor elements with an analog to digital converter, signal processing and an I2C host interface in a single monolithic CMOS sensor IC. The Si7005 is available in a “non hand-assembly-friendly” 4×4 mm QFN package, which requires reflow soldering to mount it on a PCB
Breakout module for Si7005 temperature and humidity sensor - [Link]
“Applied Science” teardown a commercial, handheld breathalyzer and discuss how it works, then test a standalone ethanol sensor.
How a breathalyzer works (alcohol sensor) - [Link]
The BME280 Integrated Environment Unit from Bosch Sensortec combines sensors to detect temperature, humidity and barometric pressure in a single 2.5 mm square 8-pin LGA package.
The chip has a quoted absolute temperature accuracy of ±0.5˚C at 25˚C and its pressure sensor features a measurement range between 300 and 1100 hPa. The relative accuracy of the pressure reading is ±0.12 hPa (equivalent to an error of ±1 m over an altitude change of 400 m) at a resolution of 1.5 cm. This pressure information can be combined with data from an external GPS receiver to achieve enhanced and faster position determination. The humidity sensor has a respectable response time of 1 s and communication with the chip occurs over the I2C and SPI (3-wire/4-wire) digital serial interfaces. In normal operation the chip cycles continuously between measurement and standby mode. The chip can also be configured to ‘forced operation’ where it remains in sleep mode until a measurement is requested.
Its low current consumption (3.6 μA @1Hz) and small size make it suitable for a wide range of mobile applications. [via]
The BME280, Three Sensors in One - [Link]
Invensense MPU6050 is an integrated gyroscope and accelerometer with 16-bit readings. It contains 2 dies, soldered face-to-face in multiple places (that’s what was causing us troubles last time!).
On the overview photo you can see how not-flat they are. On a bigger die MEMS part is 28µm above surface, on smaller die – 100 µm above. Also, there is logic right under MEMS on the bigger die.
Invensense MPU6050 6-axis MEMS IMU die-shot - [Link]
ricardouvina @ instructables.com writes:
Hello guys! In this instructable I’ll teach you how to make a very simple proximity sensor using infrared LEDs and Arduino.
Simple IR proximity sensor with Arduino - [Link]
STMicroelectronics have announced the LSM6DB0, the latest addition to its iNEMO family.
It packs a 3-axis accelerometer, 3-axis gyro and low energy ARM-based Cortex processor in a tiny 3 x 3 mm package.
This chip is designed to interface with baseband chipsets that don’t have a sensor co-processor. Additional external sensors can also be hooked up via its I2C interface, allowing the on-board processor to take care of all sensor-related functions to help minimize application latency at a system level. The device is fully compatible with all of the latest mobile operating systems including Android Kit-Kat 4.4. The sensor’s performance is the result of true 6-axis sensing, where both the 3-axis accelerometer and 3-axis gyroscope are manufactured on the same chip. They operate synchronously at the same output data rate,combinig correlated, true six-degree-of-freedom motion and not just separate acceleration and angular-rate inputs. [via]
A 6-axis Inertial Motion Sensing Device - [Link]
Raj @ embedded-lab.com writes:
A couple weeks ago I received some sample products from Dorji Applied Technologies, a china-based company that make varieties of RF and sensor modules. One of the products I received was their latest DSTH01 sensor module that carries Silicon Labs’ Si7005 digital relative humidity and temperature sensor on board. Things I liked about it are it is inexpensive (available on Tindie for only $6), compact, and most importantly it supports I2C host interface for communication.
Reviewing Dorji’s DSTH01 digital temperature and humidity sensor module - [Link]
Calibrated differential pressure sensors will find usage in industry and also in every smart home.
Ventilation, air conditioning (HVAC), or any other applications, where a pressure or a flow of air (gas) is essential, can be precisely regulated only if we know a real pressure/ flow conditions. Monitoring of fans functionality, status of filters, …, even for this purpose are very suitable differential pressure sensors from Swiss company Sensirion with an excellent accuracy and long-term stability.
As SDP sensors are differential, they have 2 nozzles. The base of these sensors is a miniature heating element and two temperature sensors. Difference of pressures will cause a small air flow through a component and it will cause a temperature difference in these built-in sensors. Temperature difference is directly depending on the amount (weight) of air flowing through a sensor and it naturally depends just on a pressure difference. A great advantage against membrane pressure sensors is a long-term high accuracy even at measuring of small pressure and maintaining of accuracy of a “zero point”.
As an air specific weight depends on temperature, measurement based only on a temperature difference of two internal sensors wouldn´t be accurate. That´s why SDP sensors have a built-in temperature compensation and linearization, thus an output of a sensor is directly a value usable for further processing. Resolution of sensors is very high and is user selectable in a range of 9-16 bits. Resulting binary value read-out through I2C interface can be divided by a constant shown in a tab. 2.1 on page 3 of the SDP6xxv1.7 datasheet and we´ll get a resulting value in desired units (Pa, bar, inch).
Universal and price-attractive series is the SDP600 (6xx) series, in which we´ll find types optimized for measurement of pressure (SDP 600/610), mass flow (SDP601/611) and types with a minimal power consumption suitable even for battery-operated devices (SDP606/616). All these types are able to measure “bidirectionally” i.e. positive and even negative values. For applications, where we know, that a pressure difference will be always positive (flow by only one direction), it´s possible to use more price-affordable types SDP 500/510 (in fact even these types measure bidirectionally, but their accuracy is not guaranteed in this range). For the most of applications no additional compensation is necessary, only it can be necessary to multiply a resulting value by a constant for an altitude compensation shown in a table 5.4 on page 6 in the datasheet.
How can be this small sensor used to measure flow of a big amount of air?
Relatively simply. All that is necessary is to make a small orifice in a pipe and this way to create a “resistance” as described in the SDPxxx_Bypass_Configuration application note. In an electronics analogy the differential pressure measurement is similar to measurement of voltage on a resistor, which depends on a current flowing through a resistor. SDP sensors can be used even for measurement of a pressure difference in a given pipe against a surrounding environment, in such a way, that one nozzle of sensor will be left “unconnected”. Naturally, such a configuration can only be used if a small leakage of a measured “gas” (air) is acceptable.
Sensirion SDP sensors measure pressure but even a flow - [Link]
BH1750FVI Is a Digital Light sensor , which is an digital Ambient Light Sensor IC for I2C bus interface. This IC is the most suitable to obtain the ambient light data for adjusting LCD and Keypad backlight power of Mobile phone. It is possible to detect wide range at High resolution.( 1 – 65535 lx ).
BH1750 Digital Light Sensor - [Link]
cbrittain1 @ instructables.com writes:
I’ve been working on re-making the the Open Hardware Pulse Sensor so it’d be “easy” to send off to OSHPark and make at home. I’m not sure but I think I started this project in March (2013) and I’ve just now finished it.
Homemade Arduino Friendly Pulse Sensor - [Link]