As we wanted to be able to turn it on and off from backstage, we purchased a battery powered laser pointer that had a switch that could be left in the on position. We also chose this particular model because it has a flat side that facilitated mounting to a plywood plate. We used a 18″ piece of 4″ dowel with a flathead #6 screw mounted into each end as contacts and telephone wire leads to provide power to the unit. A hole was drilled in the side of the battery area for the wires to come out of the body and cable was run from the pointer to a controller backstage. The control is an illuminated SPST 12VDC rocker switch mounted into a small project box. A 1.5-12V variable transformer set to 3 volts plugged into the wall provides power. We have found the variable transformers to be more useful and not significantly more expensive than single voltage units. The mounting for the laser pointer is important because it has to be easily positioned and able to be locked tightly as it was projecting to a specific point twenty feet away and had to stay constant through the five week run of the show. The unit attached to the handrail of our catwalk with U-bolts through a plywood plate. The laser pointer was mounted on another plate with double-stick tape and cable ties. Between the two plates we used a universal joint speaker mount from Radio Shack that allowed us to accurately aim and lock it down. While this swivel unit was expensive and is only sold in pairs, it was very easy to use. It should also be noted that the laser did not have to be positioned directly overhead because we were aiming at a point on top of the table. The unit was easy to build taking only about an hour of construction time. The total cost of the unit was under $150 and could be decreased by substituting a less expensive laser pointer or mounting mechanism. The unit proved to be an excellent way of spiking a very challenging unit onstage accurately every time throughout the run. Our second use of this system was during our production of A Christmas Carol to provide spike marks for actors to find an elevator location on the show's snow-covered floor. SAFETY NOTE Direct intrabeam eye exposure to laser light (looking directly into the aperture along the beam path) should be avoided. Serious and permanent retina damage can result from laser radiation. All personnel in areas where this unit is used should be given appropriate safety information. PARTS LIST (Parts numbers and prices are from the Radio Shack catalog.) Laser pointer (#63-1051) 1 $49.99 Optimus mini speaker wall mount (pair, #40-2063) 1 59.99 SPST 12VDC illuminated rocker switch (#900-7715) 1 2.25 3.3 x 2.1 x 1.1 project box (#910-5038) 1 1.99 1.5-12V power adapter 300mA (#273-1662) 1 12.99 Two-position terminal strip (#910-3208) 2 1.10 Panel mount coax DC input jack (#274-1563) 1 1.69 Total cost of project $131.10 TD & T S U M M E R 2 0 0 1 35