Giving the impression of a dying device - making a vibrating motor slow down and stop I'm trying to make a gag gift for a friend. The effect I'm trying to imitate is of a device that starts up for a moment and then putters out like something is wrong.

So I need it to:
1. Vibrate a motor for a second or two.
2. Make the vibration sputter out.
3. Light up an LED behind an error message on a paper screen.

I have very little hands on experience with anything electronic, but I have some programming and I took enough physics to know what a capacitor, etc is.

My questions are whether an Arduino is a good and cost effective way to accomplish this and is there any beginner friendly advice anyone can give me to get this accomplish
You can control the motor using PWM (Pulse Width Modulation) and make it run for full, then slowly decrease the speed till stop and after light up the led.
This tutorial from Adafruit could be a good start if you are not familiar with PWM and have also some good advices: https://learn.adafruit.com/adafruit-arduino-lesson-13-dc-motors/overview

Please be really careful about the supply source. Motors can easy draw more current then the limited available from the pins of arduino. Maybe a H-bridge could be helpfull here.(take a look at this for example of h-bridge: https://learn.adafruit.com/adafruit-raspberry-pi-lesson-9-controlling-a-dc-motor/lm293d )