Melodious warning
A gadget which will tell you with a melody and a flashing light that a houseplant needs water has been developed by APC KK, a Japanese firm. Called Do Plant, the gadget uses two 1.5-volt batteries. A weak electric current is emitted by the two legs of the gadget into the soil. When the soil is dry, the current is interrupted, switching on the melody and flashing light. The sound and light automatically stops after the plant is watered. The electric current does not harm the plant.