Wednesday, 13 January 2010

A few details

The periscope lift is about as basic as it gets but again it is effective. It is certainly not a highly engineered solution using two plastic tubes, a bit of mechano and rubber bands. The periscope is mounted on top of a plastic tube which in slides inside another tube. A slot is cut in the side of the outer tube and a bolt placed into the inner tube to protrude through the slot, acting like a small arm. A servo is mounted on a basic metal bracket and a 15cm ish metal arm(an old bit of mechano) is fixed to the servo arm. The end of the metal arm sits under the protruding bolt. When the arm lifts the center tube with periscope attached rises.Fisrt of all I used gravity to lower the periscope but found this was not very effective. I later added a loop of wire over the protruding bolt and attached to the metal arm, a bent paper clip, this acted as a return arm when the servo was reversed. It is easier to see in the top picture, simple and cheap.
On the underside of the dome you can also see the motion sensor circuit which is linked into the rear and top LED clusters. The LED clusters started life as those cheep battery opperated LED lights you get of the market,£5 for three. Just remove the battery housing, strip the housing off and power them up, via the 5v feed from the computer, they work perfectly and have been for many hours. Connecting the motion sensing circuit just adds a bit more interactivity.
Blue LED lighting on the front of the dome are just LED christmas tree lights.
Web cam is held in place with a tensioned rubber band and moved directly with a single servo
Radar eye is an MDF and cardboard surround and plastic bottle lens.

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