This smart device is able to do active monitoring of fresh concrete at any construction site to determine accurately the concrete strength by the hour. This gives an advantage to a construction site team, as is able to accurately know the exact day the concrete structural element can have formworks removed and this saves time and money. The one available here on GitHub can be customized to function without the need for a cloud server, and instead provide the information on the smart device display only. It can also be configured to do measurements upload to a local server located inside the construction site.

Nowadays there are many sensors that can be connected for this monitoring task. The most common for this kind of application is the Sensorion SHt3x, and the Maxim Integrated DS18B20 (see part list below).

This smart device has the ATSHA204A chip a SHA-256 high-security hardware authentication IC for secure and unique data exchange and communication between the smart DAQ and the Edge server.

This smart device assembly utilizes a LiPo 2000mAh battery and is able to monitor, in regular intraday intervals, and send data to a nearby edge server using WIFI or Bluetooth BLE for more than one month without requiring a recharge.

Other smart device setup solutions are possible. For instance, the one with a LiPo battery is suitable for embedding the smart device inside the concrete element itself one wants to do monitoring.

Is also possible to embed the sensor probe into the fresh concrete while the smart DAQ enclosure is placed at the surface of the concrete element. Depending on power availability the smart DAQ has a built-in micro USB plug able to connect to any USB smartphone or tablet charger.

Smart PCB Hardware Specifications

The hardware specifications for the 12bit PCB with dimensions of 54x48mm are the following:

• QFN 56 Dual Xtensa LX7 Core Processors running up to 240MHz
• RISC V ultra-low power co-processor
• 512Kb RAM;
• 8Mb SOIC 8 NOR SPI Flash Memory;
• 2.4GHz ISM wireless connectivity;
• 1x 12-16bit ADC Multiplexed DAQ channels;
• Authentication & Security:
• SOIC-8 ATSHA204A SHA-256 high-security hardware authentication IC for secure and unique communication between devices;
• Power management
• DFN-6 AUR9718 high efficiency step-down 3.3V 1.5A DC converter;
• Onboard sensors:
• DFN-8 SHT3.x; temperature sensor with a precision of 1.5C;
• DFN-8 SHT3.x humidity sensor;
• LGA-14 LSM6DS3 a 6-axis accelerometer and gyroscope;
• reference voltage sensor calibration with temperature and humidity
• External connectivity:
• 1x I2C pin terminal connector (shared)
• 1x 12 to 16bit (oversampling & digitization) digital terminal connector (shared)

In real life, this smart DAQ is able to:

• Can be powered using a 2-wire LiPo battery with a JST connector or by Micro USB
• Connect to all kinds of I2C Temperature and Humidity sensors;
• Measure voltage in the range of [0;3.3V]
• Measure electrical resistance [0; 10^6] Ohm
• Do temperature and humidity compensation on all measurements
• Has a voltage reference sensor for improved accuracy on ADC measurements
• Has a motion sensor to know if anyone moved de smart device from its place

Compatibility

• Google Home Assistant
• Apple Home
• Matter / Zigbee
• Hone Assistant

and all others compatible with the LX7 microprocessor from Tensilica.