SmartChainZ ‑ IoT Refrigerator Timestamping

With the growing popularity of Internet-of-Things (IoT) devices in mind, the IoT Refrigerator proof-of-concept demonstrates how these devices can use the speed, small footprint, and flexibility of ChainZy to implement blockchain to track metrics.

ChainZy records the times at which the unit is powered on, the compressor turns on and off, and the fridge doors open and close. Power-outages, mechanical failures, or a door left open can be detected before food goes bad. The following images show the Refridgerator proof-of-concept in action:

A. The fridge powered on with the door closed and the compressor off.


B. The fridge powered on with the door open and the compressor on.



IoT devices are becoming more common, but there is no reliable, indelible method of tracking events and metrics. As more devices are added, recording events will become more expensive.


The proof-of-concept used ChainZy capabilities to track the location, time, and status of simulated refrigerators, including:

  • the temperature of the fridge
  • whether the compressor was on or off
  • whether the fridge was on or off
  • whether the door was opened or closed

ChainZy is designed for easy interfacing and extensibility. The proof-of-concept extended a geolocation feature in browsers to add latitude and longitude coordinates to the blockchain in only 11 lines of code.


  • The metrics recorded in the proof-of-concept could be used to find trends for energy-savings, mechanical issues, and food waste.
  • Insurers can use IoT metrics to provide discounted rates.
  • Facility monitoring systems can be set up to automatically turn on generators in power-failures are detected.
  • Predictive analytics could be employed for fine-grain component servicing &mdash a new water filter can be delivered just before an old one needs changing.
  • Maintenance requests could be automatically placed before major issues arise if patterns suggesting mechanical failures are detected.
  • Alerts can be automatically sent out to owners when their refrigerator doors are left open.


ChainZy is made for both new and legacy applications and is easily extendable. It can handle artbitrary data and can be used as a platform for interfacing IoT devices. Its small footprint, low operating overheads, and speed in excess of 500 transactions per second make it IoT ready.