Finished LED connection

Now that we've tested and, if necessary, debugged, our project so that it works as expected, we're ready to solder our circuit!

Note: If you do not have a soldering iron, you may skip this step. One alternative is to coat the wire connections in hot glue (this option will allow you to fix/add/use things later, but is more likely to break), or use epoxy or a similar permanent glue (this option will be much more durable but you will not be able to use the circuit or potentially the Pi after doing this)

Quick comment about my design choices:

  • I opted for female jumper wires for the LEDs and Pi GPIO because they allow me to remove LEDs and swap colors or move them around if needed. You may skip these if you want to make connections permanent.
  • Similarly, I chose a JST connector for the pushbutton.

Onward to building!

1. Cut each of the female jumper wires in half (yes, all of them!). Using wire strippers, remove about 1/4" (1/2cm) of the wire insulation.

2. For each of the LEDs, solder a 220Ω resistor to the negative (shorter) leg. A helping hands tool can help in holding things steady.

3. Cut a small piece, about 1" (2cm) of heat shrink tube and push over the LED and resistor junction. Make sure the other resistor leg is accessible, then heat up the shrink tube until it secures the joint.

4. Insert each LED into a pair of female jumper wires.

5. Label the jumper wires (e.g. with tape), then solder jumper wires onto your printed circuit board (PCB). WIth the perma Proto board, you can use the same locations you used in the breadboard setup.

6. Next, use a (cut) female jumper wire to connect each LED to its respective Pi GPIO pin. Solder and label a jumper wire so that the bare metal connects to the positive LED leg via the PCB.

Note: Where you solder this wire will depend on your PCB layout. You can also solder this wire directly to the positive LED jumper wire.

7. Solder a 220Ω resistor to the negative (black) end of the JST connector.

8. Solder the JST connector and resistor to the pushbutton.

9. Connect the M-to-F jumper wires between the pushbutton connector and the GPIO pins (reminder: black is GND).

10. Coat connections PCB in hot glue or epoxy for a more secure connection.

Note: if you choose to use epoxy, you may not be able to use the Pi's GPIO pins for other projects in the future. If you're concerned about this, add in a GPIO ribbon cable and connect the jumper wires to that instead.

This guide was first published on Oct 22, 2020. It was last updated on Mar 08, 2024.

This page ((Optional) Build it: Finalize the circuit) was last updated on Mar 08, 2024.

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