Pi Knox is a low cost solution in RPi Zero shape and size which allows using a single 6-24V power source to power the host RPi & allow it to control two connected devices powered from the same power source.
It is on GroupGets
https://groupgets.com/campaigns/890-pi-knox & ends in 9 days!
Currently 128% funded >> Original goal set to 100pcs but since i will be making a batch anyway i decided to reduce campaign goal and make sure all interested to Pi Knox get one (or more)....
Pi Knox prototypes (blue board) work very well and the "production" version is improved adding input & output protection, increasing output power and functionality.