What is lock pinger in mongodb
There are distributed locks used in a sharded environment.  The balancer takes a lock (only one migration is active at a time), the shards will take out meta data locks when doing splits also.  Those live in the config.locks collection.

As for the lock pinger, the config.lockpings collection keeps track of the active components in the cluster, so it is an informational collection.  The lock pinger is what populates this collection and you have pasted what looks to be the result of a successful ping.

Note: please do not use these collections for anything in your application or elsewhere.  These collections (as noted on the linked pages) are considered internal only and can (and will) be changed/removed/updated without notice.