Device Health Checking

A few quick, loosely related questions.

My project consists of a number of NodeMCUs sending temperature data every twenty minutes via Blynk bridge to a RPi running a python script. Each hardware device will have its own Blynk App project.

I need to ensure that data received by the Rpi and data displayed on the App are current (ie that each sending NodeMCU is still online), and not just showing the last transmitted data, which may be many days old.

I have wrestled with different ways to achieve this but have not come up with any form of elegant solution. So, my questions:

  1. Is there any way the Blynk App can show if a device is online or not (these NodeMCUs are not set to sleep, they stay awake and just send data periodically)?

  2. Is there a simple watchdog / heartbeat function (for example a time stamp) that the Rpi could use to validate incoming Bridge data?

  3. Whilst the Bridge is working well as described, I haven’t found a way to send Bridge data from the Rpi back to the NodeMCUs - has that been implemented in Python yet?

Many thanks in anticipation,


This sounds like a very convoluted approach. What is the role of the RPI in this process? does it control some other functionality?


The Rpi collates sensor data from the other NodeMCUs and logs historical values as well as creating hard-wired alarms when certain thresholds are exceeded.

The Pi will also host a local server once the core functionality is proven.