The Sonic Boom SB200 digital alarm clock works with vibration or sound. The small vibrating pad attaches easily to the clock and can be put under your pillow. It vibrates enough so that you wake up - there's very little chance of sleeping through it. The pad is attached by a cord so make sure you do not become entangled in it. The alarm can be set to a really high 'sonic boom' level. If you are a heavy sleeper or hard of hearing, this alarm clock should help you wake.