Animated Cylon with LEDs at 32mm

A few days later and a package arrived with a few LEDs in it.

The first thing to do was to see how many tiny LEDs I could pack together into the smallest space possible. I figured that if I could solder the 0402 sized LEDs, I might be able to get up to five across, which would make for a pretty impressive “Larsson Scanner” (the thing used in Cylon helmets and – later – in KITT in Knight Rider).

I eagerly opened up the parcel and went straight to the soldering table….

0402 LEDs are the smallest consumer electronics sized LEDs you buy “off the shelf”. They’re usually placed by a computerised CNC machine. They’re absolutely tiny.

I tried to solder a couple together. The heat from the soldering iron totally destroyed a couple (the lenses on the top side de-laminated from the LED and rendered the device useless). A few I accidentally soldered together in a big blob of solder that bridged all the contacts together (despite using the finest iron tip I had).

But most of the LEDs simply disappeared.

They’re sooooo easy to drop. And when you drop one…. well, they look like specks of dust. It’s impossible to see where it’s got to!

I burned/destroyed/lost about 20 of the miserable little things before finally giving up. It seemed much more sensible to try to 0603 sized LEDs instead.

To be fair, an 0603 sized LED is still a pretty tiny little thing!

I stuck a little piece of masking tape – sticky side up – onto the table with some strips of sellotape, and pressed a row of three LEDs side-by-side.

This allowed me to (just about) get a tiny spot of solder onto each of the pads

I then ran a short piece of enamelled wire through some sandpaper (to remove the coating) and applied a thin coating of solder “tinning” along the length. This should make soldering it to the LEDs much easier.

I then taped one end of the wire down onto the tabletop, to allow me to keep it taught using just one hand, and placed it across the tops of the LEDs. With the LEDs already having solder on the pads, and there being a thin coating of solder on the length of wire, to join the two should require only the slightest touch from the soldering iron.

Aware that applying heat for any length of time to such tiny LEDs could destroy them, joining the solder together was from little more than a tap of the hot end of the iron. Fully aware that the solder joints would not be the most secure or robust, I figured that once they are inside the head of the miniature, they would be entirely encased in glue, and unable to move – I just needed the joint to hold for long enough to complete assembly….