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Searchlight

The last gadget to be added to complete the Crash Tender refit is the searchlight. The body is made from a short piece of 15mm copper water pipe. A domed piece of copper soldered to one end closes off the body. The tube is just the right size to take a 1W LED and lens. The front cap was made from a ring of copper cut from a Yorkshire fitting which slides over the body of the light. Two small nuts (8BA) soldered 180 degrees apart on the circumference of the body provide mounting and pivot points. The body is mounted to a U shaped brass bracket which in turn is soldered to a brass tube. In addition to being able to rotate the searchlight, I wanted the challenge of making it elevate. A mechanism mounted under the wheelhouse roof provides both the rotation and elevation mechanics. A small servo provides the rotation function. Two plastic gears, salvaged from a defunct inkjet printer, couple the servo to the brass searchlight mounting tube. The gear ratio gives the searchlight a rotation of 270 degrees. To provide the elevation function, a pushrod passes through the centre of the searchlight mounting tube. As this pushrod is moved up and down, it adjusts the elevation of the light via a wire connected to an arm on one of the searchlight pivots. The pushrod is hollow and tapped with an M2 thread. A length of M2 studding threaded into the end of the pushrod is rotated by a small stepper motor. As the motor rotates the studding pushes or pulls on the pushrod, thus elevating the light. A small scratch built electronic module converts the demand from a receiver channel into step commends for the stepper motor. The motor was salvaged from an old . The completed assembly was primed and then painted with Tamiya Gunmetal Grey. The LED is driven from an RC switch and constant current source and is quite bright, even in full sunlight. Graham93

4 years ago by Graham93