After I dug more into the ESP8266 WiFi shield, I got curios, why the experiences were so different between various users.
I took a look around in at aliexpress and decided to order another shield. Here is what I got now:
The one on the left is the new „shield“, the one on the right is my well known „shiald“. Apart from a few visible differences (color, maintenance pin header, different ESP8266 version), these are the differences I found so far in their functionality:
|Wires to the debug port, switches off||works as expected||works as expected|
|Wires to the debug port, switches 1+2 on||doesn’t work(?)||works as expected|
|Wires to the debug port, switches 3+4 on||ESP can be flashed||ESP can be flashed|
|Shield mounted on Arduino Uno, switches off||no connection between shield and Arduino. Serial Monitor/Flashing the Arduino does NOT work anymore||no connection between shield and Arduino. both work independently|
|Shield mounted on Arduino Uno, switches 1+2 on||no connection between shield and Arduino. Serial Monitor/flashing the Arduino does NOT work anymore||shield is connected to the Arduinos hardware serial. Communication works fine|
|ESP-Link flashed onto the ESP8266||web interface is fast and stable. WiFi connection works fine||web interface is very slow/unavailable sometimes. Connection to WiFi networks is doesn’t work sometimes|
All in all, I’d highly recommend NOT to buy any of those shields. Their design seems to be flawed. If you still want to buy it anyway, I’d recommend the „shield“ variant. Even if it behaves more stupid than the „shiald“, it seems to provide more stable WiFi. Just bend pins 0 and 1 when attaching it to the Arduino and do the wiring manually as described in my other article.
In case your project is flexible enough and you need WiFi: Just use the something like a NodeMCU instead of the Arduino. You can still program it using the Arudino IDE, but it has the WiFi build in and way cheaper than the shield (or even the Arduino).
I have also seen a Version 0.9 of this shield in some shops, but I am not willing to invest more time and money in crappy hardware for scientific reasons 😉 . If someone has some experience with it, I’d be happy to read about it in the comments.