This simple plugin can be downloaded and added to any self-hosted Wordpress site. Once activated, the site owner can add a search form to the sidebar using standard widget functionality. The form provides a text input box and some basic options, and when submitted the user is taken to the search results on the respective site. There are no custom settings, but it should be quite simple for someone familiar with Wordpress development to customise the form within the plugin code, which is released under a GPL license.
Download the plugin from www.jose-fernandez.com.es/laboratorio/wordpress-europeana-dpla-widgets/
A demonstration can be seen at www.catchingtherain.com/2015/10/europeana-plugins-test/