Some time ago I bought on ebay a pedestrian traffic light and I brought it to my home. It was laying in the basement of the house for a year or so. This summer the trafic light has found its place as a garden lantern.

The arduino board or any MCUs were not used because there would be enough a simple electromechanical components and RC circuits. The MCU is a overfunction in such project.
On the photo below is: the responsible officer, chief engineer and engineer for labor protection named laika Lana. image1

The traffic light consists from two separate sections red and green. Both have damaged locks and the green section was damaged inside and the light bulb was missing.

However, this problems were not the greatest 'barrier', everything was fixed and both sections were sealed with sealant to prevent water gets in. The largest problem was: there were no electricity supply where the traffic light was planned to be installed. At once, I would like to say that using the solar panels was not the option because the winter is quite cold (up to -30 degrees celcium) and accumulator with solar panel will not 'survive'.

In order to supply electricity to the lantern set, it was required to do some wiring works. It was decided to conduct wiring in the ground in a plastic sewer pipes which protects wire from rocks and water which could damage wire isolation. The total length of the wire track is around 40 meters. The depth of the excavated trench is around 45-50cm at some place the depth is 25-30cm.

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  • Photo #1. The excavated trench from the place where the lanters were installed.
  • Photo #2. The trench.
  • Photo #3. The junction which separates wires from source to the consumers: arbor and lanterns
  • Photo #4. The trench with sewage pipe track to the source. On the photo, the trench had already been excavated back.

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The source (waterproof junction box) installed on the fence. The RCD (residual current device) devices are installed for every consumer with defferntial current 0,03A (30mA). On the foto, the pipe ends with the rubber cap and sealed together with the tube for wiring works.

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The installed lanterns (separated traffic light). The traffic light has been fixed on a metal tube which previously was planned to use for something. The plastic track pipe goes directly to the section of the traffic lights. This is a part of the composition and also protects the wire. The incoming power supply wires is not carried directly to the section. It was brought out in the revision section of the pipe.

Lets talk a bit about specifications:

  • It is planned to use a low volatge halogen lapms 12VAC 50W electric transformers.
  • For the light on the top will be used 12VDC 30W electronic transformer.
  • For the controlling circuit the 24VDC is used (by connecting in series 2 transformers).

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The curcuit above, is the one which is used in the current design. The relay R3 STROBE is switching on and off every 1.8 seconds. The switching speed can be regulated with variable resistor and/or increasing/decreasing the capacitors capacitance. Relays R1 and R2 controls light bulbs. The SW1 is used to switch between automatic blinking (from R3 relay) and manual control from pushbuttons B1 and B2.

The primary winding of the transformer coil is supplied with 220VAC which is danger! Be careful when working with high voltages. Disconnect power before performing works!

The reason why 24V and 12V were chosen is the safety. But, in some conditions the 12VAC can be also danger in case of long exposure.

The circuit which generates the light switching (blinks) is unstable. The period between on and off depends also from the outside temperature and the variable resistor temperature.

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The internals of the control box. On the images above it is not the actual assembly, but a temporary solution whcih I used for prototyping. The enclosure previously was fitted with the relays based control circuit for the service elevator with automatic doors. The holes in the front panel were indicators. There are 3 relays, full bridge rectifier, transformers, capacitors...

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After painting and fastening the control box on the metal pipe, everything ready!
First run of the system.

The next step is decorating the installation. The bricks and fake brick texture panels on the metal carcase were used. Also the other lantern was attached to the top of the metal pipe. THe lantern was fitted with the LED tape. The LED tape is supplied by the 30W Switching PSU which was not drawed on the circuit above. All wires are hidden in the plastic pipe and metal tube.

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And almost completed decorations:

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Sorry for the low quality of the photos. It were made with the smartphone camera.

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