When Dave knew that he would be getting married in a unique London lighthouse, he decided to make some very original wedding table centrepieces: working models of the Trinity Buoy Wharf Lighthouse in which the nuptials were taking place.

Not only that, but he resolved to make ten of them – quite an undertaking. As Dave explains, “With my love of 3D printing, Raspberry Pis, and needlessly complicated projects, recreating the lighthouse as a working model seemed like the way to go.”

Trinity Buoy Lighthouse Model: quick facts

• Trinity Buoy Wharf is the site of London’s only lighthouse
• The lighthouse model was designed in Autodesk 123D
• Dave used his Prusa MK2.5 to 3D-print components
• A jam-jar is used for the glass light casing
• Dave gave most of the models to wedding guests – one is now in Australia

Buoy oh buoy!

Over a three- to four-month period, before his August 2018 wedding, Dave designed, 3D-printed, and completed the models with, unsurprisingly, “the last month being pretty non-stop.”

A time-consuming project, modelling the lighthouse necessitated a lot of work, and Dave used many photographs of the real-life lighthouse to guide his progress. In addition, as he explains, “The software I used on the Pi was pretty simple, although I tweaked it a few times. The two most challenging parts were fitting in all the printing time, and the mechanism for the rotating light. I went through a couple of major versions of that, a lot of minor versions, and still never got it 100% reliable – turns out rotating and maintaining a circuit is quite hard!”

The 3D printing time was indeed considerable, as each model required 44 hours of printing in order to produce the six key pieces: outer, inner, railing, cap, base, and base lid.

In terms of function, the models include an 18650 battery (in a shield), a Raspberry Pi, and an LCD display in the base. At the top is a warm white LED light on top of a stepper motor. “Wires run up the middle and when you turn on the battery, it powers on the light and the Pi,” reveals Dave. “The Pi then starts turning the motor (and light) and displaying various messages on the display.”

Building a model lighthouse

Understandably, the project was far from straightforward. Dave tells us that he needed to tweak the wiring, and there were a number of adjustments to the lights. “I ended up with a factory line of Raspberry Pis updating themselves and then updating their host names on the network when they were done – so I could drop onto each one the startup script, the display script, and the motor script. The display script used a Python scheduler and pulled the bespoke messages from a JSON file, so I could use the same code and then drop the right messages file on each one.”

Dave’s impressive model-making accomplishment was such an ingenious idea, and something that was, ultimately, very well received by his wedding guests, as he tells us: “I didn’t have much trouble giving them away, which was great … one is [now] in the wardroom of a navy minesweeper.”
Dave clearly has a great talent for model-making, but tells us that his next model project may be something slightly less time-consuming, “I’ll no doubt make some other things, but I don’t know what yet. I’m looking forward to making only one of something.”