AT+CWMODE=1
AT+CWJAP="myssid","secret"
After that I can ping the ESP for hours without one single "host unreachable" message.
The response time is always between 1ms and 3ms.
But as soon as I use the HTTPServer example sketch I am getting the network/temperature problems.
And the response time for a ping varies between 2ms and 180ms.
The same problems occur if I use the DHT11 example code and send my temperatures
to Thingspeak (every minute). Within one hour there are at least three gaps (1-4 minutes long) in the sent data.
I tested the sketches with 8 different ESP8266 modules bought from three different dealers.
All modules are showing the same issue. Not all are getting hot. But there are always timeslots within those the ESP is dead on the WIFI. I can see these events in the access point's log. It tells me "WiFi device is not responding".
Maybe it's not an hardware issue but a firmware bug?!