i had used lm35 for temp, humidity sensor for land humidity sendor and LDR for light.. and used a robot that moved on a line ( liike line following robot) and would transmit the parameters after stopping for a while and transmitting the data... the data is received on the othe end using a zigbee... and a LED is turned on or a fan is started, or something ... that was the green house project i did for my students... Is it the same thing you also wish to do... i used zigbee for the project...