Laser lighter

Flip-top laser lighter

Although there are more efficient ways of lighting a cigarette or cigar there can be no cooler way than by using a laser.

This project came out of a thread on Laserpoinerforums where members were discussing ways it could be done, my thoughts were along the line of:

What is "the" iconic petrol lighter? Answer Zippo flip-top, I had to find out if it can be done.

This build, though not complex is very fiddly to do as there is not much room to fit everything in, but if you want to have a go here is the information you will need.

I sketched what I planned to construct.

List of parts:

Flip-top lighter of your choice (I used a Star lighter from ebay).

Blu-ray laser diode (PHR 803T) Donated by LPF member Morgan, Thanks:)

Aixiz module (front end and lens only, Outside diameter turned down to 10mm).

Small block of aluminium (heatsink/optics holder).

Driver (I used the low range Rkcstr driver).

Push button (I took one from a broken DX green laser)

Batteries (GP 10A [9v 38ma/hr]).

Vero board.

Small pieces of scrap brass sheet, for contacts and springs.

Small piece of plastic for mounting driver and insulating battery contacts.

Various colour insulated single strand copper wire.

The first part to make is the module heatsink/mount

The width of the lighter dictates the size of this assembly the drawing shows basic dimensions The hole is tapped m3 dia.

Once the parts are made the laser diode needs to be pressed into the module, info here:

http://www.rog8811.com/laserdiodes.htm

Solder a pair of wires to the LD (solder the neg pin and the case pin to the same wire to make the laser negative earth) Solder as low down the pins as possible and trim the ends off, you need to save space to clear the lid.

The module and heatsink are glued together with 2 part epoxy. Once ahesive is set you will need to trial fit the module into the lighter. I have encapsulated the back of the LD to protect it from damage to the solder joints.

To do this you will need to remove the flint spring, wadding, wick and striker wheel. Then cut out the front of the windbreak to clear the lens.

While you are at it remove the flint tube, this is easily done by puting the end of a soldering iron into the hole, at the top, when the glue melts push the tube through.

You now need to check that the lid will open and close without hitting anything, this just requires you to use a file to take corners off where needed.

You will need to find some very flat headed or countersunk headed screws to hold the module to allow the lid to close.

Now you need to turn to the the electriconics and electrics. Cut a piece of stiff plastic so that it will push up inside the inner part of the lighter, at this stage don't worry about the notches and holes, I will come back to them.

You will need a small piece of veroboard to make the final connections on.

4 holes are drilled out (second and third from this end in 2 outer rows) to pass thin wires with the outer insulation in place, tracks cut as shown.The 4 drilled holes will need to be transfered to the plastic insulator, before this can be done you will need to drill out the flint tube hole to 8mm dia.

Push the plastic insulator into place and scribe the shape of the hole onto it. Remove the insulator, lay the veroboard on top then drill through the four holes, keeping them within the circle.

Earth return straps need to be made from bits of brass sheet.

These are bent up and stuck to the insulator with 2 part epoxy, at a later part of the build these will be bent at the ends and the excess cut off, they will stop the assembly from being pushed too far into the lighter.

At some stage you will need to set up the driver circuit to the desired output, as the adjustor will be hidden once the driver is installed, I connected it up to 9v and dummy load to set it too 110ma. Information on using dummy loads can be found here:

http://www.rog8811.com/laserdriver.htm

It may be worth noting at this point that the batteries are only 38ma/hr, using them in parallel will give around 120ma, they will not last long, but long enough to be usable. You could adapt this for a lava drive which will make better use of the batteries, I had a Rkcstr so I used it.

Cut a piece of 8mm X 0.5mm brass 25mm long, file a corner off and solder a piece of wire to one end as shown.

The Rkcstr drive can now be attached to the insulator with a dab of glue, place it with solder pads for the laser diode upermost and toward the wires.

Bend 3 wires as shown, trim them to length and solder to correct pads on the driver. Push loops into the remaing holes in the insulator and glue in place. The wires will be perfectly positioned to pass through the drilled out holes in the veroboard.

Connect the wires as shown, leave 4 long ends sticking up, these will be trimmed later.

In the flesh...so to speak.

Underside showing positive contact.

Trial fitted into the case.

I had to rethink the original plan for the negative contacts to the batteries, I was going to put springs in the bottom of the outer case. The problem with this method is that the inner case is held in place by friction, with the springs between the case and the batteries there would be a danger that the inner would be gradually pushed up and may jam the lid.

To keep the correct fit of the inner case a 7mm X 1mm slot needs to be filed in each side

Bend the earth straps out to fit into the slots and cut off to length, be sure that the assembly is pushed fully into the case or the batteries won't fit.

The following 2 pieces of brass will make up part of the negative return and also take up a bit of room to make the batteries a tighter fit.

The parts need to be filed and fitted ready for soldering.

Cut another tag around 7mm square and attach with solder to the other leg,

Fitted into the case.

There should be 1mm clearance with a battery in place, this gap is taken up by the negative spring bar.

Batteries are fitted by pushing the two outer ones into place then the middle one slides in between them. The spring bar holds them all in place.

Now would be a good time to trim the wires to length, strip the insulation and tin the ends. this is done by inserting the assembly fully, passing the wires through the veroboard. Cut the wires 4mm above the veroboard, strip insulation to top surface of the board.