I have a ventilation system in the house, which came with a RF remote:
![](http://tom-it.nl/wp-content/uploads/2017/05/img_1642.jpg)
I wanted to be able to control my ventilation system from anywhere in the house, and had some pnp transistors which I thought would be nice to use as a switch and replace the buttons.
Read MoreControlling remote with pnp for openhab