Techie’s Corner – Fire and more fire. Last month we discussed what fire could do, some of the moods it could evoke and some situations and reasons for using it. For a review, please read last month’s article available in the back issues of TRE. As with past articles, the illustrations are not currently supported by our archive storage. So, if you read the article and would like to see the illustrations, please feel free to contact me and I will send them to you. Last month we looked at a battery operated fire effect. This month I will describe a line voltage (USA 120VAC) device. This device can be made to imitate the flickering of a fire, a TV set or any other low level, random flickering light source. The device involves a 15 to 40 watt, 120 volt lamp, and a fluorescent starter and miscellaneous wiring for each lamp you use in the effect. Note: There are many types and brands of starters and some starters will need a ballast to provide sufficient power to operate the lamp. If your circuit does not work without a ballast, it will be cheaper to buy another type of starter than to buy a ballast. The starters cost between $ .50 and $3.00, ballasts run $15 to $30 each.
The starter is the main ingredient in the mix. Starters are the small silver cylinders about 1 ½” long and about ¾” around that fits into one end of older type fluorescent fixtures. They are available at most home improvement stores, hardware stores, Home Quarters, Home Depot et. al. A starter is basically an electrical capacitor that gives a short boost of voltage to start the old style (slow start) type of fluorescent lamps and then turns off. In a fluorescent fixture the starter is then out of the circuit until the switch is turned off and then on again. In our effect, the starter is wired in series with the lamp and is “in the circuit” all the time.
When the switch is turned on, the starter is “off” but it starts storing up voltage. At a certain point the voltage builds up and “overflows” causing the lamp to light up. The starter is now “empty” of electricity and “shuts off” causing the lamp to be dark. It is kind of like a bucket under a faucet that is hinged to tip over when the bucket is full and to tip back up when it is empty. In the fluorescent fixture the starter only operates once each time the fixture is turned on, therefore it is not important just how consistent or accurate the starter is. The impreciseness helps in our circuit because no two lamps will blink at the same rate.
For most fire effects, at least three or four lamps should flicker and one should be on for a steady background effect. If physical space in your fire unit permits, as many as nine or ten lamps may be used. As you increase the number of lamps you can lower the wattage. However a mix of different wattages makes a more realistic effect.
To wire your effect you will need a starter for each lamp, a socket for each lamp, a male Edison plug, wire, wire nuts, a plywood (or similar) base. You may wire a switch into the circuit or design the wiring to plug into a switch box that you already have on hand. The most critical part of the wiring is the starter. There are two small prongs on one end, most look like the head of a nail that is sticking out about ¼”.The starter should be fastened down in some way, hot glue, plumber’s strap, heavy rubber band, Velcro strap etc. The wiring must not contact the outer case of the starter in any way. The easiest way to connect to the starter is to use small, insulated alligator clips available at Radio Shack. This makes changing the starter very easy if necessary. You can also solder directly to the contacts. The wiring is fairly simple as shown in the illustration below.
To add color, refer to last month’s article for a complete description of using gel (color media, Lee, Rosco, GAM etc.) to enhance the effect.
Next month I will be on vacation, but in August’s column we will take a look at the centuries old but still effective, “Silk Streamer Fire Effect”. Hope you enjoy the articles, have a nice summer.
Don’t sweat the small stuff and remember…….it’s all small stuff!