Add Hunter BTT (BLE) as plugin

[BasvanH]

Hi,

I'm reverse engineering the BLE protocol for controlling my Hunter BTT irrigation valve. As Im already using ESPEasy within my home ecosystem, I was thinking about writing a plugin for it.

Im using the NimBLE library to communicate with the Valve. I want to readout the battery status (done). I wish control open and close of the valve (done). And I wish to change it operating mode, schema / manual / disabled (WIP).

Plugin features:

• The plugin should support those features above.
• Additionally Im thinking about a BLE scan window so you can select your BTT as we need it's MAC address to communicate to. Manually enter the MAC could also be possible.

I currently own the single valve version, there's also a double valve version. I can add support but I then need to BLE traffic dumps.

My questions:

• Because the value is not really a sensor but a device, does this fit well within this ESPEasy project?
• Im a beginner in Arduino, Im able to build the parts for communication with the devices but not sure if I can write the whole plugin so perhaps some help is needed.

Regards,
Bastiaan

[TD-er]

Well it is just like a switch, so it would fit perfectly well in the ESPEasy architecture...

However (there is always one of those ;) ) we currently have not any Bluetooth related code integrated in ESPEasy so far.
Problem with Bluetooth on ESP32-xx is that it is using the same radio as WiFi.
So it is an exclusive-OR to use either Bluetooth or WiFi.
It can be done as some other projects already have shown, but it will be quite tricky to get the timings right between interacting with Bluetooth and WiFi or else either one may get a poor connection.

This is one of the reasons I have not yet looked into Bluetooth myself to integrate it into ESPEasy.

I am currently doing a complete rewrite of the WiFi/network related code, so I can keep this in mind.

N.B. not all ESP32's support the same Bluetooth. So that's another caveat for adding Bluetooth support.

Does your test setup use both WiFi and Bluetooth?
Is it loosing its WiFi connection, or acting 'sluggish' when communicating with Bluetooth?
You could try to let a ping run from any other computer in your network to the ESP and then see if it is still stable while interacting with Bluetooth.

[BasvanH]

Im currently testing/developing with the ESP32 connected with USB cable, so not via WiFi yet, I was not aware of this challenge. For this project it would be mandatory to use WiFi in combination with Bluetooth. I started this project to extend the very short Bluetooth range of this value over WiFi and off course add automation via ESPEasy.

These are my board details:

• PLATFORM: Espressif 32 (6.9.0) > Espressif ESP32 Dev Module
• HARDWARE: ESP32 240MHz, 320KB RAM, 4MB Flash
• Chip is ESP32-D0WD-V3 (revision v3.1)
• Features: WiFi, BT, Dual Core, 240MHz, VRef calibration in efuse, Coding Scheme None
• Crystal is 40MHz

I will include WiFi in my test to see what happens.

[BasvanH]

I did some testing. I enabled Wifi and Webserver and created a simple page that triggers some BLE commands. When BLE is connected, the webpage is very unstable, not usable. When BLE is disconnected, the page works fine. After some researching I got it working stable with these code parts:

#include <WiFi.h>
#include <WebServer.h>
#include <NimBLEDevice.h>

WebServer server(80);
// WebServer task for core 0
void WiFiTask(void * parameter) {
    for (;;) {
        server.handleClient();
        delay(10);
    }
}
void setup() {
    // Start webserver on core 0
    server.begin();
    xTaskCreatePinnedToCore(WiFiTask, "WiFiTask", 10000, NULL, 1, NULL, 0);
}

From what I understand it puts Webserver on core 0 where also wifi is serviced from. BLE is serviced from core 1. This works for me on a 250 lines sketch. Ping to ESP32 is fluctuating a lot, between 6 and 500ms.

[TD-er]

I expect the only way to get this stable is to let the WiFi negotiate a longer DTIM with the AP and keeping track of when a beacon interval is about to happen.
Inbetween those beacon intervals you can then handle Bluetooth.

But I think the only real stable option is to use Ethernet when using Bluetooth.