Wireless Indoor Environment Monitoring System

Over 65% of employees work indoor. If the indoor ventilation is insufficient, the air quality deteriorates through accumulating contaminants. In 1992, the World Health Organization (WHO) defined “Sick Building Syndrome”; which describes that abnormal symptoms such as eye, nose and throat irritation, and asthma attacks are caused by air pollution within buildings. Indoor environments impact human health and quality of life/work, so it has become essential to build indoor environment monitoring systems that help overcome these issues.

At present there are multiple sensors available from many silicon vendors to measure various environment parameters and also connects to an embedded hardware and software for specific functionalities such as data logging and uploading to the cloud to understand the present state of the environment and any subtle changes. Such sensor-based embedded systems are often used to monitor the temperature, humidity, pressure, and indoor air quality. For large indoor area where multiple sensors are needed to monitor and wired connectivity becomes complex and costlier, many wireless technologies are available which do not have space constraints and will be more cost-effective too.

Embien being the experts in multiple wireless technologies has developed a wireless indoor environment monitoring system for a renowned IT firm with access to the cloud server and Android applications.

Customer Requirement

The customer, a leading IT firm needs to monitor their working environment condition from time to time to ensure proper ventilation for their employees and also for maintaining good environmental conditions. The working space is quite large and a lot of employees are working, so the ventilation factor is more important. They also need to maintain light intensity levels in the work table at the standard brightness level. In addition to the local monitoring via smartphone, they also require an update of data to their server periodically and also alert them in abnormal conditions.

Challenges and Solution

Multi-parameters measurement such as temperature, humidity, pressure, indoor air quality, lux and occupancy detection using a single device with an accuracy of data in fast-changing and vast environment was a challenge. The traditional method of installing wired sensors on different floors was costly but they felt that going wireless was too complicated due to lack of experience with software and cloud integration.

Embien proposed a customized design of self-powered wireless sensor device including off-the-shelf integrated environment sensor for multi-parameter monitoring. Bluetooth Low Energy connectivity is chosen for local wireless communication and a custom Android application is developed to run in any Android smartphones for accessing the parameters. A gateway device is designed for acquiring the parameters/events from the wireless sensor device and upload the same to the cloud server. WiFi and GPRS is chosen for cloud connectivity.

Wireless Environment Monitoring

The wireless sensor device is powered by NRF52832 BLE SoC from Nordic semiconductor. The sensor is connected to the SoC via a suitable interface and the parameters such as pressure, temperature, humidity, and IAQ are periodically acquired. These sensors will provide raw values and necessary formulas are implemented to get useful data. In addition to the environment sensor, the device had PIR and Lux sensor for movement detection and light intensity measurement respectively. The acquired environment parameters, movement detection, and light intensity data are sent to the cloud and smartphone in a particular format in a fixed time interval.

Block Diagram of Environment Monitor

The device was powered by three AAA battery and power consumption of the device is optimized such that the device will operate for 1.5 to 2 years. The battery charge level is closely monitored and the same was available in the packet format.

Wireless sensor devices are deployed at the various locations under concern. Multi-purpose gateway bridges the gap between sensors installed at the various location and the cloud server. The gateway device is powered by ARM Cortex-M4 based MCU, NRF52832 BLE SoC for sensor device interface, and either WiFi or GPRS. Also any Android smartphone under the vicinity will have access to the data from the sensor device using a customized Android application.

Embien has provided its extensive support throughout the project and the customer is satisfied with our services. Once the data is available to the customer on cloud and local smartphone, the immediate actions were taken more effectively.

Feel free to get in engage with us in realizing your Sensor and BLE based design along with our hardware and software development expertise.