Some LEGO robot designs allow you to readily remove the NXT or EV3 brick without otherwise disassembling the robot.* One can then swap in an Arduino or Raspberry Pi in its place. (Given a suitable shield.) The Raspberry Pi could make use of a neural compute stick for example. Arduino has sensors for humidity, odor, rain, barometric pressure, etc.
* Damien Kee's RileyRover being one example.