Smeaton's Tower Background

Smeaton's Tower stands as one of the most notable landmarks in Plymouth, UK. This lighthouse was originally built in 1759 on the Eddystone rocks to warn oncoming ships of the dangers which lay ahead of them. For 123 years, this lighthouse served it's duty off the coast of Plymouth, until it was decommissioned in 1882. In this same year, almost the entire light house was dismantled and rebuilt on the Plymouth Hoe as a memorial to the engineer John Smeaton and his pioneering work in lighthouse design. The lighthouse doesn't function anymore and has only been lit with candles once in 2009 to mark the 250th anniversary of it's first illumination.

The Working Smeaton's Tower Model

This model is a roughly 1:100 scale replica of the tower as it stands today on Plymouth Hoe. From some measurements I found online, with a few of the original design documents, and using a range of photographs, I created this model at a 1:100 scale from scratch in Fusion 360. Some elements could not be reduced accurately in the 1:100 scale some artistic licence has been taken in the thickness of the wind vane and the railings around the lamp room. As the real Smeaton's Tower has not been illuminated in over 265 years, I thought it would be a fitting tribute if my model could have a real working light and act as quirky table lamp.

Features

• Rotating lamp to simulate a real lighthouse
• Secondary interior LED to illuminate the body and shine out the windows
• Multi-part printing to reduce plastic waste and allow multi coloured printing without the need for an AMS
• Easily assembly with lock and key cut-outs to align pieces correctly
• Quirky desk lamp or artistic display piece for a minimal cost!

Printing

The first print profile for the “Working Lighthouse” includes plates for each of the separate parts in their colour as seen on the real Smeaton's Tower. These are already split into the correct object parts so it is easy to recolour them if you wish to shape the lighthouse to your own personal design! I have included a brim on both the roof section and the main body just to ensure good bed adhesion, although this will also put a brim over the screw holes (this can either be removed or just screwed straight through). There are no supports required for any of the parts and the model was designed with this in mind. Printing at a 0.2 layer height works great, but printing the roof at lower layer height does help to hide the layer lines, I ended up using a 0.16 layer height version for mine.

The second print profile for the “Model” is a simplified version with less pieces if you just want to print the lighthouse model without adding the electronics or the working lamp room. This is also split into 3 separate parts for easy construction, and each segment can still be recoloured if you want a funky rainbow lighthouse model!

Working Lighthouse Bill of Material

• 3D Printed Parts
• Arduino Nano
• White 5mm LED x 2
• 220 Ohm resistors x 2
• SG90 Servo
• SPDT Slide Switch (I got these from Amazon)
• Small amount of wire (any thickness between 26 AWG to 30 AWG)
• M3x8mm countersunk screw x 4 (Attaches base to body)
• M2x5mm screw x 6 (Attaches servo and Arduino)
• M2x4mm screw x 2 (Attaches switch)

Build Guide

Once you have finished printing all the parts remove any brims and clean up any blemishes/strings if you have them. Then it is time to start working on the electronics.

1 - Solder two wires to the switch

Cut two short lengths of wire ideally at least 10cm long and strip both the ends a few millimetres. Tin the wires with your soldering iron and then solder one wire to the centre pin of the switch, and the other wire to either of the remaining pins. Trim off any wire extruding to keep everything neat and to avoid potential short circuits.

2 - Solder wires and resistors to both LEDs

You will require two wires for each LED (and I would recommend red and black to help your remember which leg is positive). For one LED you will need two wires at least 30cm long, and for the other two wires at least 10cm. Strip both ends of all the wires a few millimetres and tin them with the soldering iron. Trim down the legs of the LEDs slightly so they are about half the length and solder one wire onto each leg (ensure that the black wire is soldered to the negative leg, the negative leg can be identified by the flat side on the body of the LED). Take a resistor and solder it to the other end of each of the black/negative leg wires.

3 - Thread the LED wires and place the LEDs in position

For the LED with the longer wires run the wires (and resistor) through the top cut-out in the “Lamp Rotator” column, then feed the wires out the side of the column, and finally down through the semi-circular slot at the bottom. For the LED with the shorter wires run the wires (and resistor through the top cut-out in the “Base Plate” column, then out of the side of the column. Feed the wires through carefully until the LEDs sit neatly in their housing. To keep them in place a little hot glue or super glue does a great job (just be careful not to glue the wires in place!)

4 - Attach the servo

The servo screws into the bottom of the “Railings” section and has a cut-out so it can only fit in the correct orientation. Hold it in place and secure it with 2 of the 2x5mm screws. When flipped over you should see that the centre of the servo is in the middle of the housing.

5 - Attach the Lamp Rotator

Take the wires (and resistor) which are coming out of the lamp rotator and carefully feed them through the cut-out next to the servo in the “Railings” section. Once they are pulled through press the rotator down onto the servo gear and with a little pressure it should slip on. You should now be able to turn the lamp rotator and hear/feel the servo move. By turning the rotator (and thus the servo) all the way until it stops in the clockwise direction you put it at the “0” position. Once it is in this position, pull the rotator back off slightly and position it so that the hole where the wires pass through the railing section is at the furthest counter-clockwise section of the semi-circle cut-out in the “Rotator”. This ensures that when the servo moves that hole in the “Railings” will always line up with the semi-circle cut-out.

6 - Attach the Railings Section to the Body

Feed the wires for the servo and LED down through the body from the top, and align the key notches on the “Base” with the cut-outs on the “Railing” until the two pieces fit together. You can glue these sections together but it makes it harder for maintenance and troubleshooting, so I would recommend doing that at the end when everything is finished.

7 - Solder everything up to the Arduino

This step can be a little fiddly, but if you have left yourself enough wire it isn't too bad. (If you still have a JST connector on your servo, cut it off, strip the ends off the wires and tin them first). Run each of the cables through the correct pin holes on the Arduino from the front and solder them into place from the back:

• Lamp LED black/negative wire (solder resistor attached) - GND
• Lamp LED red/positive wire - D5
• Body LED black/negative wire (solder resistor attached) - GND
• Body LED red/positive wire - D7
• Servo orange/signal wire - D3
• Servo red/positive wire - 5V
• Servo brown/negative wire - GND
• Switch wire 1 - D9
• Switch wire 2 - GND

The order of the switch wires doesn't matter as long as one goes to D9 and one goes to GND. As the Arduino Nano only has two GND pins you will either have to double up connections to each pin, or do as I did and run an additional cable from one of the GND pins and solder both the resistors from negative side of the LEDs to this wire. It is also worth putting some electrical or insulating tape over any exposed metal particularly around the resistors to just help prevent any short circuits. Finally remember to trim off any wire which is protruding from the Arduino when you have finished soldering.

8 - Finally assembly

First take the switch and on the inside of the lighthouse “Body”, put the switch through the top cut-out in the lighthouse door. Use the two 2x4mm screws to secure this in place by screwing it into the support posts it rests against. This can be a bit tricky due to the angle, but is much easier if you have a small magnetic tipped screwdriver.

Next take the Arduino and position it on the posts in the lighthouse “Base Plate” so that the screw holes line up and the USB port is pointing towards the nearest edge. Use four 2x5mm screws to secure it in place. Don't worry about over tightening these screws just make sure that they have bitten through into the posts below to hold it in place.

Now carefully take all the wires and feed them up into the body of the lighthouse as you start to put the base plate on, being careful to not trap any wires. The bottom of the “Base Plate” has part of the door on it, so use this to help line up with the door on the “Body” in the correct orientation. Use the four countersunk 3x6mm screws to secure the “Base Plate” to the “Body”, these screws should sit flush in their countersunk holes when tightened all the way.

You can now take the “Lamp Room” and push this down over the top of the “Lamp Rotator” ensuring that it is in the correct orientation so the keyed cut-outs line up to secure it. This can also be glued into place using super glue (or hot glue). The “Roof” can be placed onto the “Lamp Room”, also being aligned using the four cut-outs. As with the last section this can be glued into place if required although I found both of these pieces to hold together perfectly well with no adhesive. Finally you can slot your “Wind Vane” into the small slot ontop of the sphere on the “Roof” (I even painted mine gold to give it the finishing touch of the real Smeaton's Tower).

9 - Software upload

I have already written the required Arduino script which you can find included in the extra documentation below as “Arduino Code.txt”. Download this file and copy and paste all of the text into the Arduino IDE (available for download for free here). Compile the code to ensure there are no issues, then plug your lighthouse into your computer with the appropriate USB cable (the USB port for the Arduino can be reached through the lower slot in the lighthouse door). Upload the program and you are good to go! Flicking the switch in one direction with start the lighthouse working and when flicking the switch in the other direction the lighthouse will “shutdown” returning to its initial position before shutting down the lights.

10 - Enjoy your quirky lamp!

It produces some wonderful light in a dark room and even illuminates the pattern of the lamp room onto nearby walls, which looks quite beautiful!