KEMO Electronics (germany) make these items. They have an interesting
range of
small modules with various functions. Have a look at their web page:

http://www.kemo-electronic.com/en/module/m029/index.htm

They are wholesale only, but have distributors around the planet.

This should be the best solution, but (up to now) they don't answer to my
email...

73 de Riccardo IK5WQO