How to: Laser Projector inside a Lighter
The following is a post by Rog8811, our lasers expert. As a designer and engineer I am always looking for ways of converting everyday items into cool gadgets. This iconic lighter, known around the world, is the Zippo flip-top lighter. Having already turned a flip-top ligher into a blu-ray laser lighter I decided that I would see just how much more could be done with one.
This time round I wanted a laser spirograph projector . What follows is a tutorial that will show the major parts that are needed. All fliptop lighters are slightly different in size and shape you need to adjust sizes and positions to suit your host. I started off by getting a host lighter engraved.
Then followed a number of drawings to see what the options might be. There are a lot of parts to get in so everything needs to be as small as possible (obviously)
The only way I could be sure to get everything lined up was to do away with the inner slide and replace it with a machined out block of plastic with all the parts fitted. To get this as large as possible the plate in the lid that operates the lid closing catch needs to be removed, to do this drill a couple of holes through it then break it off with a pair of pliers. Remove the rough edges with a small grinding burr in a dremil drill.
Here are the basic dimensions for the block but, as previously stated, adjust to suit your host.
The green laser module was stripped out of a keyring pointer that ate batteries within seconds, so it was no loss. This would be heavily modified to fit as it is 12mm diameter and too long with the drive circuit attached. (there are smaller green modules available that will fit more easily but I had this one to hand). I turned this one to 10mm diameter…. the thread that holds it together is 10mm diameter and consequently I had to glue the 2 halves together with superglue wheh it fell apart, it may be better to drill out the hole it fits into to 11mm diameter and turn down the module to suit.
For a spirograph pattern to be produced a minimum of 2 rotating mirrors are required. These were cut from an acylic mirror tile, it is important to get the hole dead centre, to do this I drilled a 0.5mm hole into a piece of 7mm diameter brass, stuck the back of the acrylic to this and turned to size in a lathe, (once stuck to a mandrel you can carve the mirror to size with a craft knife). Then use a pin chuck to drill into the acrylic from the back.
The mirrors are driven by vibro motors from mobile phones. The ones used were 5mm diameter once the rubber cover was removed.
The motors and mirrors were mounted in brass shrouds to protect them from damage. The motors are held in lpace with a dab of superglue.
The mirror must be stuck on at a very slight angle so that when a laser is reflected from the spinning mirror the beam describes a small circle.
The laser and the motor assemblies were pressed into holes machined into the plastic block, all three parts were wired up to check the output beam, to get good patterns you may have to reverse the direction of one of the motors.
A Battery housing with positive and negative contacts was machined to house a rechargable 3.6v battery then wiring was started.
Wires soldered to motor 1 and battery holder
The driver for the laser and the switch were located with super glue and wired.
The other battery contact and laser module wired. (it is important to remember that green laser modules are positive ground) I soldered the battery contact to the module to stiffen it up, this connects the positive directly to the module which is no bad thing.
This is what the finished item looks like. The piece of metal on the top is a magnet�from the lens focus assembly of a PS3 sled, it takes the place of the lid closing catch that disapeared with the inner slide of the lighter.
This is what it does…. (my camera is not fast enough to capture the patterns produced by the projector).
A longer view gives a slightly better idea of the output.
A short video of the laser can be viewed below:
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June 26th, 2009
I imagine that if you varied the speed of one of the motors it would create different patterns. Perhaps you could make the position of the lighter cap control a variable resistor to do that.