Introduction: LIndesnes Fyr Lighthouse Clock

About: Im engaged in electronics, laser cutting, crafts, plants and nature, bikes and photography,sailing, graphics etc.

I found this very cute lighthouse paper model (thank you Gunnar Sillén !) at the page of Lindesnes Fyr: and, as I ´m also interested in model trains (H0 gauge) I decided to scale the model to 1:87.So far a nice Model.

But what about the light function? One solution could have been to just add a blinking diode or, more sophisticated, reproduce the original signage of the lighthouse (FFl W 20s) as noted in the sea map.

But for my home that did not seem very useful. So I came up with the idea to use the lighthouse model as a clock.

What you will need:
For the electronics:

1 arduino nano V3 or compatible

1 1307 RTC module with I2C

1 transistor universal NPN

2 resistors 150 Ohms

1 resistor 1k Ohm

1 small breadboard and connection cables

1 LED 2812b

2 LED 20mA yellow

1 small speaker8Ohm/0.25W or piezo transducer

For the cardboard model:

Color printer

colored or white cardboard to make the paper model

if you are good at cutting cardboard with scissors and knive use them.

If you have access to a laser cutter – fine. But you have to prepare the cutting files - ore use mine.

Step 1: Preparing the Paper Model

If you have no access to a laser cutter,

print out the cutout-sheet PDF provided by Gunnar. Scale 1:250 on A4 or scale 1:180 on A3

Cut out all the parts with sharp knive and scissors.

If you use thin paper it may be necessary to line the walls and roofs with aluminum foil so that they wont light up entirely with the LEDs installed. Only the windows should be transparent.

I used red cardboard for the upper part of the lighthouse, white or yellowish cardboard for the rest.

For the lantern and windows I used polypropylene sheet and for the outer lantern-window 0,5mm clear acrylic sheet. Cut out the window panes and glue the transparent parts behind the cardboard at the inside of the buildings to get „real“ windows.

For lasercutting: You will have to convert the PDF into a usable vector file for the machine. I use CorelDraw and you will find my file attached to this instructable. There are lots of double lines and filled shapes from the converted PDF to be converted in simple lines and you will have the colors to be adjusted so that the laser will get the apropriate instructions from your file.

I use red layer for cutting, green layer for laser dot (bending lines!) and black layer for engraving.

The power adjustment and speed of the laser depend on the available machine.

Step 2: Making the Paper Model

Bend the parts as needed and glue them together according to Gunnar´s instructions on the cut-out sheet. A fast curing glue is advisable as the cardboard often is a bit tensioned and you have to fix the parts until the glue has cured.

The tower is open from the bottom side so that you can access the lantern and the inner part of the powerhouse to install the LEDs.

If all goes well you soon have a cute little lighthouse – still without the red lantern part on top..

Its advisable not to mount the lantern without prior installing of the 2812b Neopixel. Just make the lantern part separately and mount it after the Neopixel is tested and then properly fastened at the bottom of the transparent lantern. . I will get to this later when we talk about the circuits.

Step 3: Wiring Up the Circuits and Programming the Arduino

Wire up your circuit
according to the breadboard layout.

The LEDs will not be placed directly on the breadboard as you will want them inside the model buildings. Just solder some leads to the LEDs long enough to mount them inside the buildings.

One of the yellow LEDs is for the bottom part of the lighthouse tower and the other is for the powerhouse.

The Neopixel is to be mounted directly at the bottom of the transparent lantern assembly. You will provide a piece of cardboard between lantern light and the bottom part of the tower to prevent blinking the tower windows. Only the lantern should be lighted by the neopixel.

Now connect an USB cable to the the arduino and your computer, load the sketch using the arduino Environment and see if all the functions work as intended. You will want to have a look at the serial monitor.

The RTC clock should get the actual time from the computer and be adjusted at first use.

If for some reason the adjustment must be repeated(e.g. if the buffer battery had to be replaced or in case of some malfunction), comment out the corresponding if-structure in the setup code and reload the sketch. After this remove the commenting to regain the original code.Upload the code again.

Next, the Serial monitor will print out the current time e.g. 12:48 . Then the neopixel will start blinking and you will see the numbers of the blinks at the serial monitor e.g. 12 4 8.

There will be a long white blink for each full hour from zero to twelve. Then a single blue blink follows, indicating that you now get the next value: Minutes divided by ten. The Neopixel will blink green accordingly followed by a single blue blink. Last you get short red blinks indicating the remainder of minutes division. To tell the time from the blinks just add: Hour(s), ten(s of) minutes and remaining minutes.

E.g. if you get two white blinks, three green blinks and four red blinks it will indicate 2:34.

I did not make an indicator for am or pm. You may alter the code if you want this e.g. by changing the single blue blink to pink if it is am and to blue if it is pm.

Now you will see the sound function that powers the „foghorn“ at each full hour, except by night, as you may want to sleep without foghorns. It is this line of code (still in 24h mode):

if (Stunde < 20 && Stunde > 9)

The yellow light inside tower and powerhouse will light up while the foghorn is silent at night and vice versa. Change the code to have these functions going off at different times if you want.

Step 4: Basement - Room for the Wires

Breadboard and wiring will not fit easily inside the model. It is possible to mount the circuits inside the powerhouse, but I preferred to make a suitable box for the breadboard electronics with a cutout in the lid to mount the paper model on the box and still be able to access the openings for the leads. A hole at the back side will allow for the connection of a micro-usb cable to the arduino later. I provide a file for laser cutting the box from 3.2mm plywood, too.

Step 5: Assembly of Electronics and Paper Model

Mount the electronics inside the box and keep the usb of the arduino aligned with the hole at the back of the box. Most breadboards are provided with self adhesive tape, so its very easy to mount.

I glued a small wooden horn to the speaker to make the sound of the "foghorn" more realistic but you need not do this.

Now test the function of all parts before glueing the upper (red) part of the lighthouse on top of the tower. Once you have mounted the red lantern part to the tower you will no longer be able to access the neopixel.

Step 6: Painting and Finding a Nice Place to Put the Model

Now your lighthouse is finished , the lights are blinking the time code and the foghorn will sound at full hours. What remains is some painting to make the model look more realistic. I used acrylic paint for the terrain and roofs and for the „rocks“ I mixed white glue with some sand. Green sponge flakes will do for tiny plants.

Plug the USB to a suitable wallwart to supply 5 volts 500mA power and as the RTC keeps the time as long as the built in battery lasts, you may put the working model where you want it without connection to the computer.

Remember to save the code for the day the backup battery fails or if for some reason you have to readjust the RTC.


And perhaps you want to vistit the real Lindesnes Fyr to hear the powerful diaphone at the "Day of the Fog Horn" that is celebrated every year with some thousand visitors to experience the sound of a gone but once important navigational help.

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