An alert system for alerting a hearing-impaired person including a wearable unit to be operatively worn on the body of a user, wherein the wearable unit comprises: (i) a plurality of differently coloured light sources; (ii) a vibrator; (iii) a means for receiving a sound event signal; (iv) a rechargeable battery for powering at least the light sources, the vibration generating means and the receiver; (v) a strap or band for securing the wearable unit to the wrist of the user; and a plurality of sound-detecting units, wherein each of the sound-detecting units is differently coloured with a colour corresponding to the colour of the one of the coloured light sources on the wearable unit, and further wherein each of the sound-detecting units comprises: (i) a means for detecting sound; (ii) a means for transmitting a sound event signal in the event of a sound detected by said means for detecting sound being higher than a predetermined threshold sound; and (iii) a rechargeable battery for powering at least the sound detecting means and the signal transmitting means; wherein the wearable unit is configured to, upon receiving a sound event signal from a sound-detecting unit, activate: (i) the vibrator to generate a vibration for alerting the user; and (ii) the coloured light source corresponding to the colour of the sound-detecting unit from which the sound event signal is received, so as to visually communicate the colour of such sound-detecting unit to the user and consequentially, the location at which that sound-detecting unit was previously positioned. a wearable unit to be operatively worn on the body of a user, wherein the wearable unit comprises: (i) a plurality of differently coloured light sources; (ii) a vibrator; (iii) a means for receiving a sound event signal; (iv) a rechargeable battery for powering at least the light sources, the vibration generating means and the receiver; (v) a strap or band for securing the wearable unit to the wrist of the user; and (i) a plurality of differently coloured light sources; (ii) a vibrator; (iii) a means for receiving a sound event signal; (iv) a rechargeable battery for powering at least the light sources, the vibration generating means and the receiver; (v) a strap or band for securing the wearable unit to the wrist of the user; and a plurality of sound-detecting units, wherein each of the sound-detecting units is differently coloured with a colour corresponding to the colour of the one of the coloured light sources on the wearable unit, and further wherein each of the sound-detecting units comprises: (i) a means for detecting sound; (ii) a means for transmitting a sound event signal in the event of a sound detected by said means for detecting sound being higher than a predetermined threshold sound; and (iii) a rechargeable battery for powering at least the sound detecting means and the signal transmitting means; (i) a means for detecting sound; (ii) a means for transmitting a sound event signal in the event of a sound detected by said means for detecting sound being higher than a predetermined threshold sound; and (iii) a rechargeable battery for powering at least the sound detecting means and the signal transmitting means; wherein the wearable unit is configured to, upon receiving a sound event signal from a sound-detecting unit, activate: (i) the vibrator to generate a vibration for alerting the user; and (ii) the coloured light source corresponding to the colour of the sound-detecting unit from which the sound event signal is received, so as to visually communicate the colour of such sound-detecting unit to the user and consequentially, the location at which that sound-detecting unit was previously positioned. (i) the vibrator to generate a vibration for alerting the user; and (ii) the coloured light source corresponding to the colour of the sound-detecting unit from which the sound event signal is received, so as to visually communicate the colour of such sound-detecting unit to the user and consequentially, the location at which that sound-detecting unit was previously positioned.