My latest emonpi device not show wlan0 interface what is happening?

Hi, sorry to hear your having trouble.

When did you order from us? Do you know your order numbre? Do you know if you have the latest RaspberryPi3 with on-board Wifi? If you do one side-plate on the emonPi enclosure will be black acrylic plastic.

If you ordered some time ago and have an older RaspberryPi 2 you will need an external Wifi USB adapter.

If you have SSH access you can find out what RasPi you have by running:

$ grep 'Revision' /proc/cpuinfo | sed 's/.*: //'

If this returns a02082 then you have the latest RasPi3 with on board wifi. If it returns a01041 then you the older RaPi2 without on-board wifi. See here for more info on hardware identification: