I've just finished writing an instruction sheet for my IoT students on creating an ultrasonic distance sensor using the SRF05 device.
Please note the SRF05 works off of +5v and ground, and needs a level shifter to convert WeMos signal levels to/from the device.
DO NOT connect the 'Echo Output' signal directly to the WeMos - you must use a level shifter.
Note: There are details about level-shifters on the last page of the Ulltrasonic article.
Hope you enjoy reading this article as much as I enjoyed writing it.
Cheers from David