LED Strand

LEDs & Resistors

To illuminate the details in the body of the guardian robot, I  fashion together a strand of red and blue 3mm LEDs. These are not programmatically controlled, rather are simply ON or OFF – this is mostly just for aesthetics. You don't need to do this portion of the guide if you don't want – albeit is time consuming to create a strand of LEDs. Their are easier ways to achieve a similar effect, perhaps with these pre-made LED strands.

LED Strand

I used 6x 3mm LEDs to make the strand. A mix of reds and blues to give it some color variation. You can add more or less to your strand depending on how bright you want the body details to glow. I found six to cover most of them, this is a hexapod after all ¯\_(ツ)_/¯

Add Resistors to LEDs

I proceeded by prepping the LEDs and resistors by trimming all of the legs short. Then, tinning all of the electrodes with a bit of solder. After that, I soldered a 220ohm resistor to each of the cathodes. 

Wires for LED Strand

We'll need two more longer pieces of wire to connect the LEDs together in series. The LEDs will be spaced apart ~6mm so the strand needs to be roughly 4cm in length. Measure, cut, strip and tin the two wires.

Self Adjusting Wire Stripping

Next, we'll need to create gaps in the wire that run across the two. Essentially stripping insulation in-between wires, creating segments to which we can solder the legs of the LEDs. To do this, I used a self adjusting wire stripper. With it, one can strip multiple pieces of wire at once. This features a set screw for fine tuning the grip for thinner 30AWG wires.

Solder LEDs to Wires

With the LEDs and wires prepped, we're ready to solder them together. You'll want to tin the exposed ares of the wire with a bit of solder. I highly suggest using a pair of helping third hands to hold an LED in place while soldering them to the wires. It's also handy to hold the wires in place with a pair of tweezers as the wire can get hot if left over the iron too long. Notice the orientation of the wires and LEDs. Repeat this process for all of LEDs to complete the strand.

Test LED Strand

Make sure you've checked all of your solder joints to ensure they're solid and not bridging. Once the strand of LEDs was finished, I tested it out using a coin cell battery – Super quick and easy way to test LEDs. Now is a good time to adjust wire lengths and use some heat shrink tubing to keep the wires together.

This guide was first published on Jul 18, 2017. It was last updated on Dec 09, 2018. This page (LED Strand) was last updated on Jul 25, 2017.