In order to create an alternating light sequence on the Christmas tree, the string of LEDs need to be cut at various points. Keep in mind that the ground connection can remain common across the string, so you can decrease the number of wires that need to be soldered.
Did you know?
LEDs have polarity, meaning there is a positive and negative connection. When hacking the Christmas tree, be sure to only cut the positive wires since these will connect to the Propeller I/O pins through the S2 hacker port.
Most Christmas tree LEDs look like the one shown above. The flat spot on the LED package designates the negative connection, so be sure to not cut that wire.
- Cut the LED string on the tree in a few places, keeping the ground wire intact.
- After cutting the wires, strip the cut ends so that about 0.25” of wire is exposed.
- Cut the pluggable female wire to the desired length and strip the same amount.
- Before soldering, twist the two wires together to create a mechanical bond.
- Solder the wires together, using the soldering iron to heat the wire from the bottom and add solder to the top. Then, insulate the connection with heat shrink tubing or electrical tape.
- Open your S2 by removing the six screws on the bottom of the robot.
- Connect the Christmas tree wires to S2 Hacker port. For a cleaner display, thread the wires through the S2 pen port to hide them. Connect the positive LED wires to pins 2-5 on the Propeller, and your ground wire to one of the ground pins.
- Put your S2 Robot back together and attach the tree to the top of the case using Velcro or double-sided sticky tape.