Blynk for Beginners and help with your project


Just here to say that, damn, I love this app! I’m just with very basics with programing and you made my life much easyier with what you made!


split this topic #66

A post was split to a new topic: Hii I am very new to Blynk please help me


Hi, I think this is what do I need to turn on a wave maker for my aquarium, I have 1 doub, in this example uses an boolean variable named ONStatus and initializes it in “FALSE”, when this variable change the value to “TRUE” value?


What is this?

We are going to need a lot more info before we can offer a fix.


a doub!!!

Why it’s so hard to answere?


Well either he has a doubloon (AKA a Spanish gold coin) and wants to get latest bitcoin exchange rates… or he is referring a variable in double() format… could go either way :stuck_out_tongue:

Darnit @Costas don’t bother trying to figure out the users confusing riddle and just give the answer 42 :stuck_out_tongue_winking_eye:

Any info on converting IP Cam streams into Video Widget

Sorry my bad english

Now I understand that you are playing around, thanks for the help!


Yes, just joking a bit. But, if you can explain in more detail… or create your own topic and use your native language, that might be easier?


I think he means doubt. Would probably have been better to say he has “1 question”.

If you’d tried googling you would have found the answer in a matter of seconds.
Boolean variables can be true or false (no quotes, all lower case).
You can also use 1 and 0 instead of true or false,

This forum is for Blynk related questions. Yours is a basic C/C++ programming question and doesn’t need to be asked here.
If your coding knowledge is poor enough that you have to ask this question, and your inability to help yourself is such that you come here to ask the question rather than googling it, then you are likely to have many Blynk specific questions along the way. My advice would be to save up your ‘good will’ credits and use them wisely rather than asking basic programming questions here.



Look @PeteKnight I apreciate your time for “answering” just was asking about: when in the code example the bool variable turned to TRUE state, I’m aware about a what a boolean variable is used for, despite your answere I was reading better the code and I got understood it. So if my questions bother you, you have the option of not answering or ignoring me, if this help you to live happy. The subjetc that I was write on it was named “Blynk for BEGINNERS and help with your project”. You are right about something, I have a lack of searching, apreciate you point it. Working on it!

Some times the beginners have made a mistake or asking obvious questions. Must to know it


Ok @Gunner going to do that. Thanks!


I think we all get a little happier in life with the ability to offer some constructive feedback… don’t take it personal :slight_smile:


Ok @Gunner I’ll take it in that way


HI ,I’m newbie to Blynk and I’m confused how to used it. We have this project using particle photon with blynk of course, we will be able to on the light using the slider widget. The idea is I can control the brightness of the light.Please help me.


Particle uses its own timer libraries, BlynkTimer (SimpleTimer) as used in the post you are referencing, will not work with the Particle sketches.

You can read about this here as well…

Check on the particle site for more information on their timer.


Apologies @AdrianStivalet. Based on your comments and after the-reading your question, I think I misunderstood your original question. I thought you were asking “If I initialise a variable as false, do I set it to true if I want the opposite condition”.
It appears that you were actually referring to existing code where a variable is initialised as false, but you couldn’t see where it was later changed to true.

I guess that you’ve now spotted that this is in one of the If statements in the code.



Hi @PeteKnight thanks for your apologie, I was trying to take your answer as @Gunner told me, like a constructive feedback but I apreciate you take the time to do apologize for. I’m not an rookie at all but some times “meto la pata” as we say here in México :smiley:
Kind regards


Do i understand this correctly? These are the four lines that actually do the work.

> BLYNK_WRITE(vRelayBtn) {     // Blynk app WRITES button status to server
>   vRelayStatus = param.asInt();
>   if(vRelayStatus == 1){
> digitalWrite(relayPin, LOW);        //

2-nd. Line vRelayStatus is getting last recorded state from the server?
3-rd line . If recorded value is 1, Then do give high signal on physical board pin too. ?

So is this mean that if the last state of the button and led in blynk mobile app and led/relay on physical board was on, i can physically unplug the power of the board,and after that plugged it again.That will automatically give high value on the physical pin of the board led/relay again?


@Ivanivanovvv No, not quite. What you are looking at is part of a basic Blynk Function (missing some syntax). One that gets called (AKA ran) each time the corresponding widget changes state.

But there are other commands that will acquire that state from the server upon MCU boot, and depending on your code, will call these functions upon bootup.

However, at this time I recommend you start your own current topic with the questions you have, and showing the code you are working with.