Yam2hip is a project mainly written in ..., it's free.
Syndicates Yammer to Hipchat
This is setup to run on Heroku. Some config (environment) variables need to be set.
I used these instructions to get an OAuth key: https://developer.yammer.com/api/oauth2.html
export YAMMER_OAUTH=v7tFEGTrCIITH4ye5YtzeQ
I got a Hipchat auth token here: https://yourcompany.hipchat.com/group_admin/api
export HIPCHAT_TOKEN=f37d39c7ef92a85b0761efd18fdf78
And used that to figure out the room id: https://api.hipchat.com/v1/rooms/list?format=json&auth_token=f37d39c7ef92a85b0761efd18fdf78
export HIPCHAT_ROOM=23108
On Heroku, that looks like this...
heroku create appname --stack cedar
heroku config:add YAMMER_OAUTH=v7tFEGTrCIITH4ye5YtzeQ HIPCHAT_TOKEN=f37d39c7ef92a85b0761efd18fdf78 HIPCHAT_ROOM=23108
git push heroku master
heroku scale clock=1