ESP32 Data Transfer

[Sparky49]

Hi,

I've been doing some very simple experiments with an ESP32 module running an Arduino core recently, as part of a project where I'd like to control the duty cycle of two PWM lines from an android app through a wifi connection. I have some basic skills in C, but very little experience in interfacing with existing code/protocols etc - mostly I've just been writing simple embedded stuff.

Whilst I've managed to get the ESP to toggle a GPIO on or off by changing the url through a browser, or by clicking a hyperlink on a server created on the ESP using example code, I don't think that this would be ideal for controlling two separate duty cycles, as you'd need to have a whole host of urls to send data. Is there a more efficient way of sending data to my ESP32 via wifi? I envisage that it would likely take the format of a string, say "A32" for pwm channel A at 32%.

I have seen services like Blynk, but would prefer to stay away from such things as they seem to make it too easy - I want to learn about the processes involved, but my inexperience in this field has it seem a bit daunting. Any further advice regarding how to learn how to understand these processes would be appreciated too.

Thanks in advance.

[GeorgeOfTheJungle]

Can't use url parameters? Like this:  http://device/pwm?dutycycle=45

[Sparky49]

That seems so obvious now you mention it. 

Perhaps that would be best for me to use until I get more familiar with the systems in play. Thanks George, much appreciated.

[GeorgeOfTheJungle]

You're welcome!

[JustMeHere]

You want to use a REST style api.  The example above is a start.

[rjp]

their are 3 main options.

custom udp or tcp - open a raw socket straight to a custom daemon on some server type machine.
this one is good for learning but also means you need recreate alot of wheels.

http - usually REST,  easy to do,  relatively slow and resource heavy

mqtt - very lightweight and has some nice features like distributed events, eg: you can extend it to other lights without changing the main code.
potentially makes things more complicated with maintaining multiple daemons, if you dont like that sort of thing.

[Sparky49]

Thanks JustMeHere and rjp, alot of terminology I have never come across but will have fun reading up on!

Fwiw I managed to get the method mentioned by George implemented, and just finishing off by fiddling around with some interrupts now. I will definitely have a look at the other methods mentioned though.