Bedazzler: DIY non-lethal weaponry

Step 7 Build it: Attaching the PCB, Lenses, and Finishing Touches

The PCB is cut down and tucked into the slot behind where the reflector went (image 7a)

The plate sits in front, sadly its just slightly too small to go into the enclosure. However, this way there is more space for the heat sink. (image 7b)

Lenses are snapped onto the LEDs. I used superglue to tack them down. This is a major mistake so don't do what I did because then the fume damage the lenses and they need to be cleaned. There's probably a better glue to use. Perhaps epoxy? (image 7c)

A 9V battery is wired up to the arduino. All the lenses are put on (image 7d)

We cut out a simple lens protector from acrylic on our laser cutter. (image 7e)

Showing the fit before we finish. (image 7f)

With some gaff or packing tape to attach the lens protector, we're done! (images 7g & 7h)

Comments

[rohang]

Take one of those to a concert or to Disneyland... lol

[The Lightning Stalker]

Wood glue will work as long as there's not much flexing and shock.  It has the advantage of being removable in case some of the LEDs burn out.  Like any adhesive, everything has to be clean or it won't stick.  Epoxy will work also, but be very difficult to remove.  I've been using Gorilla Glue™ recently, but you have to be careful to only use a little bit because it will expand.  The other surface has to be moistened.  Huffing on it is usually sufficient, but you have to be quick, though, since it evaporates quickly, as you know.  You could also try melting the plastic onto the circuit board with a soldering iron, but that will likely have an even weaker bond than the wood glue.  Then there's double stick tape, of course, which the manufacturers like to use.  Another adhesive is the 3M™ carpet or corner bead adhesive in the spray can; but it's really expensive and you have to be really careful not to get it on the LEDs or lenses.

[Benson1]

Hey, I'm an amateur at most things electronic and I had aquestion.  Why would melting the plastic onto the circuit boardhave a weak bond?

Just so I have future reference...

[The Lightning Stalker]

For  some  reason  Instructables  is being  crappy  and  deleting  spaces  in my  comments.

The 3 main reasons are:
Most people don't clean circuit boards after soldering. Melt plasticonto that and it will pick up the impurities and get weak and brittle.
The melted plastic and the object it's melted onto have to be the sametemperature for a good bond.
Few types of plastic can tolerate heating to liquid or semisolid withoutbreaking down.

Hot glue might also work well, but only if you're very meticulous inapplying it.  Unless the board and plastic are very clean and getheated to the same temperature as the hot glue, the bond is fairly weak.
It also has to be a 'hot melt' type gun to get the best bond.
The glue shouldn't be applied until the gun is up to temperature.
The glue melts before the gun is fully heated up since it's designed towork with 'cool melt' guns.
Hot glue won't adhere at all to some plastics. It might look like it's"stuck", but come apart later - probably when you need it most.
Hot glue will absorb cigarette smoke and this will get between the gluean 'workpiece', weakening the bond.
One trick I use on perforated board is to force the hot glue throughsome of the holes and out the other side.  This greatly improvesthe bond.
I don't usually recommend hot glue because of all thesecomplications, but it  can work if done right. It's quick and easy,so it's used a lot in the industry. There are specialty glue sticksaround that can overcome some of these limitations if you look around.Also, keep in mind that hot glue will melt when a soldering iron getsanywhere near it and will really screw up a joint you're trying to solder.