In the past few months, we have covered a few smart shower monitors that help you conserve water and save money. You could always build your own using Intel Edison. Chris Miller, Mayo Tobita, and Sarah Wever have shared a guide on Instructables showing how you can use an Intel Edison Board to build a simple shower use monitor.
Blue detects when you enter the shower and starts a timer. The goal is to shower under 10 minutes. Once you have exceeded the limit, the device
intercepts you shower time playlist and begins to blast Nickelback with the only way to stop it being to turn off your water.
You are going to need an Intel Edison board, Grove Base shield, Grove button, a few other parts to get started. More information is available here.