This is a coastal tide clock made with a K40 laser cutter using Ordnance Survey data from their open map service. This is a tutorial showing you how you can make one using your own location.I cut the map using a K40 laser with an upgraded smoothie board if you haven’t got your own laser cutter there are many offerings on the web or join a local hackspace.
I think the contours provide a pleasing and interesting aesthetic and the tide marks on the face provide additional compass reference points for the map so high tide is North low tide is South. The maps work best when you are featuring a section of coastline!
Once set, the mechanism is synchronised with the Lunar cycle 24 Hours 50 minutes to the day. The mechanism rotates twice per day approx, 12 hours 25 minutes per cycle corresponding with the two high and low tides of the day.
The clock below shows Porthleven in the UK
Materials:
- 3mm Oak veneered laser plywood – i got mine from kitronik https://www.kitronik.co.uk/
- A tide movement mechanisim – https://www.ebay.co.uk/itm/New-Quartz-Tide-Tidal-Clock-Movement-Mechanism-Motor-90mm-Straight-Hand-Fittings/172022388554?epid=1151063360&hash=item280d55574a:rk:1:pf:0
- Some super glue – I use Gorilla Glue
- Some blue watercolor paint for the ocean
Step 1: Get the Data
- UK Map – Head to the ordnance survey webpage to download their OS Terrain® 50 ESRI Shapefile https://www.ordnancesurvey.co.uk/opendatadownload…
- US Map – I haven’t attempted to cut a US map but the data here seems to be in the same format as the UK data https://topotools.cr.usgs.gov/contour_data.php
- Other areas – Contour shapefiles tend to be publicly available through governmental scientific agencies for a lot of countries it just takes a bit of searching
Step 2: Locate the Data
Head over to QGIS and download and install their open source GIS application.
- Add a new vector file using the tool in the top left tool bar
- You now need to navigate to the specific OS50Terran file for the area you want to create. For the UK data you are looking for an AutoCAD shapefile its usually the largest file of the set. To make things easier you can narrow down the search by identifying the grid ref appended to the file name..Unfortunately narrowing down past the region is a bit of trial and error until you find the right tile.
Tip* You can open a series of files and they will start to join up to create a larger area
Once you have your desired area we need to export a SVG over to illustrator to prepare for the laser.
- Click ‘New print composer’ ignore the name box that pops up then a new window will open
- In the new window that opens click ‘Add new map’ and draw a bounding box on the white space – your map should now appear on this canvas
- Now click ‘Export as SVG’ in the top toolbar
Step 3: Prepare for the Laser
We are now going to prepare the file for cutting –
Open Illustrator alternatively GIMP the open source vector program.
We now need to separate into layers what we are going to ‘cut’ the coastline,’ and what we want ‘etched’ the contours…
- >Select All
- >Give all paths a single colour eg Blue and reduce stroke weight to 0.01pt
We now need to create a separate layer for the coastline and move the coastline paths on to this layer and color the stroke to red.
Note the layer structure in the screenshot – please use the template ‘Laser Clock.svg’ file on the github to make it easier to understand https://github.com/ginandtronic/tideclock
The final step is to create the shape of the map perimeter depending on the size of the clock template you use. I used a 150mm round size. So i created a 150mm diameter circle around the map, as this was a cut path i set the colour to red and stroke to 0.01pt
Then you’ll need to create the frame of the clock using either your own ideas or copy and paste my design from the github templates.
Your file is now ready to send to the laser cutter.
Note the red lines below are the cut lines and the blue lines are the contours/etched areas
- The central cut out forms the bottom/sea layer. Paint it blue and glue the contours onto this.
- Then glue the clock surround to the edge of the map layer.
- Mark the centre of the clock and drill a 8mm hole to allow the fitting of the mechanism.
- Adjust the indicator hand by turning the “adjust wheel” so that it points at the high tide position at the published time of the local high tide, then insert an Alkaline battery.To obtain the most consistent results from your tide indicator clock, it is important that the initial setting is as exact as possible and then left alone until a new battery is required. – Daily adjustments will cause inaccuracy.
