What’s inside a Dräger Multiwarn II gas detection warning system used in mining, oil, chemical, and emergency services etc to detect hazardous or explosive atmospheres.
Intrinsic safety design and how both catalytic bead and infrared IR gas detectors work, and pellistors. And a teardown of a Hydrogen Sulfide (H2S) sensor.
EEVblog #603 – Gas Sensor Teardown – Dräger Multiwarn II - [Link]
The MAX31730 temperature sensor monitors its own temperature and the temperatures of three external diode-connected transistors. The operating supply voltage is from 3.0V to 3.6V. Resistance cancellation compensates for high series resistance in circuit-board traces and the external thermal diode, while beta compensation corrects for temperature-measurement errors due to low-beta sensing transistors.
MAX31730 – 3-Channel Remote Temperature Sensor - [Link]
This is a 1-wire absolute pressure sensor based around the Motorola MPX4115A:
The 1-wire weather group is always looking for new sensors and ideas that will allow them to monitor more and more elements, the 1-wire barometer is just one of these sensors. Based around the Motorola MPX4115A absolute pressure sensor, the group has been trying to design / decide on a good interface circuit for quite a long time.
The most commonly used and my personal preference is the Bray series. Both the version 1,2 and 3 designs use the same amplifier with adjustable offset and gain presets, the main difference between the three versions is that the second two versions have dual voltages, 5v and 10v with the amplifier being powered from the 10v rail, this way the amplifier has a greater output range which uses the full input range of the DS2438 ADC, subsequently giving better resolution capabilities.
1-Wire Barometer Project - [Link]
The “EasyPlug Shield” for Arduino makes it super easy to connect sensors to your Arduino. The EasyPlug shield provides an incredibly simple, clean, and quick way to connect sensors to your Arduino board. They have sensors for just about anything.
All of our sensors are designed to be easy to use, right out of the box. Plug in a cable (provided) and the sensor is ready to go. We’ve picked the most useful and fun sensors for you. But we’re adding more all the time, so you should be able to find a sensor to fit your needs.
EasyPlug: The Sensor Shield for Arduinos - [Link]
This project consist of Arduino board, serial TFT LCD 128×160 display, DHT22 sensor and obviously bread board and jumpwires.
- Temperature measurements : -40 – 125° C, +/- 0.2° C
- Humidity measurements : 0 – 100% , +/- 5 %
- Update rate 2 s
- Humidex(“describe how hot the weather feels to the average person, by combining the effect of heat and humidity.” ) is calculated based on measurements
- Humidex digits color varies and represents affect on humans.
- Black and white display themes.
Arduino based Temperature and Humidity/Humidex meter with DHT22 sensor and color LCD - [Link]
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]