Naturally I wanted a case to hide the wire spaghetti my Arduino project had become, and so I set off looking for a way to make my own. But my box of 100mm turned out to be a nightmare of construction.
My little circuit controlled the lights in my room. When I entered at night the lights would turn on. The system used remote plugs which were controlled by an RF module. It worked perfectly, but to anyone who wasn’t its proud father it was an eyesore.
Laser cut plywood was my material of choice. It seemed easy and cheap compared to the 3D printed alternative. I wanted the edges of the square box to interlink so I could avoid using screws.
Designing with Illustrator
My first disaster was Illustrator. I needed to draw the 2D plans using the line tool. It was a painstaking job, but I managed it. However I was left with a sense of uncertainty. Will the joints fit together? What if my box needs resizing?
DigiHaus, who I was going to use to laser cut the box, taught me about kerf. Laser kerf is the amount the laser cuts away from the material. If I were to cut a 100mm length in half I wouldn’t be left with two 50mm lengths. More like two 49.92mm lengths. The kerf can range from 0.08mm to 0.45mm depending on the material. Since I didn’t take into account the kerf my measurements were all wrong. And I had decided mid-design that I wanted to use 6mm thick ply instead of 3mm which would have changed the kerf amount. Designing on Illustrator was near impossible.
So I bit the bullet and downloaded the free 3D modelling software SketchUp. It’s basic, but it can do the job – I thought. There’s a great article on Instructables detailing the exact process. Since SketchUp didn’t output the required format I was to install a plugin. I’d be left with a 2D plan in SVG format. Hours of box designing joy passed before I realised that the plugin no longer worked with the newer version of SketchUp. In fact I couldn’t get it working with any version of SketchUp. And even if I did I still had the problem of kerf.
A last stab at a solution was googling “laser cut box generator” to which I discovered MakerCase. An algorithm would calculate everything for me. Dimensions, kerf, thickness, tab sizes. Within a few minutes I had a box, in 2D format, as an SVG.
I opened the plan in Illustrator and drew in the holes I needed to make the sensors and Arduino fit. I had a reliable box plan within half an hour. So I sent it off to DigiHaus for a quote. £75.
Laser Cutting Myself
I’m one of those ‘young professionals’. It’s what they call people in their 20’s who have a job but still can’t afford nice things. So £75 was a tad too expensive. Instead I thought I’d learn to use a laser cutter myself.
Hackspace is a communal work area in East London. They have the titan of laser cutters and it costs only £6 per hour (plus £15 per month membership and £5 training). The space is extremely popular and I’m still waiting for a place on their training session.
It’s worth mentioning Autodesk. They’ve changed since my college modelling days. What used to cost more than a month’s rent is now a manageable subscription service, and they’ve added a load of great tools for hobbyists.
123D Design is superior to SketchUp, letting you export designs to their other programs like 123D Make, which will help you laser cut or 3D print the model. Unfortunately 123D Make doesn’t yet support the interlinking joints I needed and seemed to lean more towards laser cut sculptures.
Etsy is amazing, not only because everything is hand made, but because most sellers are willing to alter their product for you. While frequenting it I found Praktrik who sells laser cut puzzle boxes (and incredible furniture). The box was near enough the size I wanted, super cheap and the seller only asked for 2 dollars extra to add a few holes. I was quoted £7.76.
Praktrik was kind enough to take some scribbles I had done on Illustrator and apply them to his box design. He also offered to cut the boxes in other sizes.
Etsy was clearly the easiest and cheapest option, so if you’re after a perfectly fitting enclosure seek out little companies like Praktrik who are up for modifying their existing products first.
More complicated boxes will obviously need to be designed by you. Expect to pay for software, 90% extra in cutting costs, and a good amount of design time.
Of course the ideal is to find a communal laser cutter like the one at Hackspace and cut with your own designs. Box generators are a life saver if you have a cutter but no design knowledge.
I expect wait a little longer before I get to this stage, but for now Etsy is perfectly fine.