Help to configure mqtt anemometer

Hi
I have set up this anemometer with mqtt and esp8266
In esp8266 I have set the following

const char* mqtt_host = "myip";
const char* mqtt_id = "myID";
const char* mqtt_topic_prefix = "anemometer/wind";
const int mqtt_port = 1883;
const char* mqtt_password = "mypassword"

It is working ok. I can get values in MQTT Explorer and at MQTT page of HA is the state topic anemometer/wind

I am trying to add it in HA like a sensor with the below configuration but it is not working
No values at all. I can see for a few seconds a value of 0 and then disappears,

- platform: mqtt
    name: "Wind Speed"
    state_topic: "anemometer/wind"
    unit_of_measurement: 'km/h'

Now that I deleted the above sensor it works again, I am getting the below values

Listen to a topic
 
Listening to
anemometer/wind
 
Message 7 received on anemometer/wind at 12:10 AM:
0
QoS: 0 - Retain: false
Message 6 received on anemometer/wind at 12:09 AM:
0
QoS: 0 - Retain: false
Message 5 received on anemometer/wind at 12:09 AM:
6.61
QoS: 0 - Retain: false
Message 4 received on anemometer/wind at 12:09 AM:
9.48
QoS: 0 - Retain: false
Message 3 received on anemometer/wind at 12:09 AM:
0
QoS: 0 - Retain: false
Message 2 received on anemometer/wind at 12:09 AM:
9.48
QoS: 0 - Retain: false
Message 1 received on anemometer/wind at 12:09 AM:
5.22
QoS: 0 - Retain: false
Message 0 received on anemometer/wind at 12:09 AM:
0

Can you help set it up?

ok. I kept the minimum setup and it is working.

- platform: mqtt
    name: "Wind Speed"
    state_topic: "anemometer/wind"

What kind of anemometer do you have?

Eltako Windsensor (http://amzn.to/2ps1Tte - German Amazon)

Its in the first link of my post to github