An electric toothbrush wherein the number of revolution of a motor shaft is in match with the frequency of reciprocating motion of the brush. The cultivating unit comprises one or more cultivating members adapted for breaking the soil and throwing it upwardly into the soil treating chamber, and the heat exchanger being in thermal communication with the heat generating unit, the bellows adapted for drawing ambient air, passing the air through the heat exchanger and throwing hot air into the soil treating chamber. The support rack is formed from multiple interconnected segments. The sending rate may also be tuned in reaction to changing network conditions based on messages from the receiver on a separate feedback channel to keep datagram loss rates below a specified upper bound.