Data Rate - Minimum

A simple question I hope. I have a simple temperature monitor that I wanted to send data to Blynk at different rates (from 1/sec to 1/30min or only on significant delta).
This is a battery powered device so minimum wifi usage is desired.
However I was challenged with the Older Blynk. If I did a cycle and re-connected within 2-3 minutes - it worked as expected. But once I broke the 4-5 minute time - the reconnect would not work smoothly

So question is: What is the minimum data rate that must be maintained before the “device” is flagged OFFLINE or DISCONNECTED? And/or is there a “periodic check” by blynk to know if the device is still “connected”??


Is it essential that your device appears as “Online” when it’s in deep sleep (and actually offline)?


Appear ON line is NOT critical currently. I just wanted to know “when” Blynk Server would declare a device as “disconnected”.
And is this via a sequence from my Device OR is there a “periodic ping/check” used - or ???


As I noted - with the original version - seemed I stumbled into 3 different time windows. Where my things acted as if they were “still active” - Where a typical log-on cycle was needed (long sleep) - but a time where it just took a long time to connect (longer than clean log-on) and sometimes this took multiple cycles.

Thanks again.

It’s done via a heartbeat/ping process, the frequency of which can be adjusted via #define BLYNK_HEARTBEAT

There’s also an “Ignore offline period” but several people have reported that this is buggy in Blynk IoT, but I’ve not tested it myself.


Ah - super thanks. Final query in the DOCs I see default is 10sec - and the example shows using 60sec – is there an upper limit??

Again - thanks for your time / responses / and Blynk overall. :grinning:

All of mine show 45 seconds in the bottom left corner of the DEvice Info screen in the web console…


Not sure. This guy was using 600 seconds. It would be worth dropping this stuff into Deepl translate if you want to know more…


Thanks so much - will play around a bit once I get fully migrated. I am still able to use my “local server” - but want to get everything moved over.

Again my thanks to you and the entire group.

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So as i start the code rework - the “perhaps obvious” thought manifests as to how the server side is designed for “sleeping devices”.
I understand the idea of the PING approach to know if the device is online - great approach.
However I don’t know if a single missed ping will flag as offline - or if multiple pings need to “fail”. So that is query one.
The second query is "If I manually send data to blynk server does this RESET the ping timer. Idea being if I wakeup between PINGs and send data does that keep the device ONLINE. I realized that even with a multiple minute ping time - if i am sleeping the chance of being awake is fairly low (almost like lottery).

Again many thanks

I believe that a single unreturned heartbeat will do that, yes.

What do you mean by “manually”?

If you mean using the HTTP(S) API then no, it does not.
If you mean that your device wakes then connects to Blynk then the server knws that the device is online again and what you call the “ping timer” is re-initialised.

It might help if you turned BLynk Debug on and watched the data exchange between the server and the device. This topic might help you to understand the results…


Pete - Excellent - again many thanks for the product and your great response time.

Will play with the DEBUG - great reminder