Vibrate iPhone every second
Yes, there is a way. 

Here's how on the iPhone (with pictures):


Download Pro Metronome by EUMLab
Use the large scroll wheel in the center to set the tempo to 60 BPM.
Press the button in the bottom left labelled "4/4"

From there, subtract the "beat" option until you see "1/4"
Tap the top area of the screen to go back to the main page.

Tap the pink rectangle in the top left until it is grayed out. This will prevent the phone from making a noise.
Tap the settings icon in the top left.

Enable the "Vibrate" option.
Go back to the main screen by tapping the right side of the screen.

Press the play button! The phone should vibrate every second until you close the app or the battery dies.