Introduction: Arduino Traffic Light

This instructable is derived from: Arduino-Traffic-Light-Simulator

I have used the drawing from this instructable, to create a separate traffic light. I made the following changes:

  • Holes for LEDs are smaller, for 5mm LEDs (instead of 10mm LEDs).

  • Added tiny platform, so the traffic light can stand on its own.

  • Changed the shape, so that it can be used for material with thickness of 4mm (instead of 3mm).

Note on cost: Since 5mm LEDs are cheaper then 10mm LEDs and 4mm plywood is cheaper then 3mm acrylic, this is a 'budget' version of the traffic light.

The traffic light can be connected to (and off course programmed with) any microcontroller (such as Arduino UNO).
Tip: use an Attiny 85 development board if you wish to keep your entire project very small.

With many thanks @ pcvnes for a very good and clear instructable! I really appreciate that even includes instructions (lesmateriaal) in Dutch!

Step 1: Parts List and Tools

The following parts are needed:

  • 1 red LED, 5 mm
  • 1 yellow (or orange) LED, 5 mm
  • 1 green LED, 5 mm
  • a piece of plywood, 4 mm thick. Size is about 11 cm x 12 cm.
    Or acrylic or any other material that can be cut with a lasercutter, as long as the thickness is 4 mm.
  • 4 jumper wires:
    • a red, yellow, green wire, 10 cm
    • a black one, 15 or 20 cm
      I have used wires that correspond with the colors of the LEDs, if you don't care about the colour, 2 jumper wires will be enough, as they are cut in half.
  • 3 resistors, 330 ohm
  • a bit of scrap wire (3 cm or so)

To turn the traffic light on, and to program it, you also need a microcontroller (such as Arduino UNO) and 4 jumper wires to connect the traffic light to your microcontroller. This part is not included in this instructable.

The following tools are needed:

  • a laser cutter (see next step if you don't have one)
  • a soldering iron (and a bit of solder tin)
  • something to strip the jumper wires with (I used a sharp knife (stanleymes) for this)
  • wood glue

Step 2: Cut Out Parts

Cut out the parts with a lasercutter. The base (square with the cross-shaped hole) needs to be cut out twice.

I have used the laser cutter from my local FabLab.

To find the FabLab closest to you , visit:

I assume you could also print the drawing on a piece of paper, stick it to plywood and use a hand (fret)saw, and drill the holes. Or even use strong cardboard. I have not tried it though.

Step 3: Assemble Parts

Assemble the parts, as described in step 3 of this instructable:

Because the LEDs are smaller then in the original instructable, you may not be able to connect all LEDs without an extra piece of wire. I needed one piece of wire of 2,5 cm (from the red LED to one of the resistors) so I used a piece of wire left over from another project. If you don't have wire left over, you could also use a piece of paperclip (leg of a LED, resistor, etc.), this also works fine.

Because I do not own tools to put 4 dupont pins at the end of a wire, I have cut 4 jumper wires in half. Strip the end of each wire. Solder half a jumper wire to the end of each resistor (red wire at the resistor that has the red light, yellow to yellow, green to green). Then solder a black jumper wire to the green LED, the anode (minus or short) pin.

Notes/ tips:

  • Jumper wires can be male or female. Males are recommended if you plan to connect your traffic light to a breadboard or Arduino UNO. Females if you plan to connect to an Arduino Nano or Attiny 85.
  • It is most easy to attach LEDs, wires and resistors, before gluing the parts together.

  • Because you only need half a each wire for 1 traffic light, you could used the 4 pieces of wire left over for a second traffic light.
  • The first time, I stapled the wires to the wood for extra strength, this was a bad idea. The wires do not stay in place, and it's easy to damage them. The second time, I used a drop of hot glue, this worked much better.