The interface has an 8 digit LED display showing readings for either micro-Sieverts (µSv), counts per minute (CPM) or Banana Equivalent Dose (BED). This last one is an unofficial unit of radiation exposure. The idea is that people can relate to the idea of radiation exposure from eating bananas (bananas contain radioactive potassium-40). Sieverts or REMs are meaningless to everyone but scientists. Banana Equivalent Dose is about equal to 0.1 µSv.

There are three touch switches that toggle between the three units. When one is selected it will light up.



There is also a "mute" touch button that disables the click sound when a particle is detected.



And then there is a LED that lights up when a particle is detected and has a fade effect over a second or so.



Finally I used a number of additional LEDs that are lit when the machine is on. They are just for looks.



I wanted a modern or sci-fi style interface. This meant it definitely needed a touch screen rather than mechanical switches. After some serious research (time wasting on Google) I settled on a LCARS style. This is the style used in Star Trek. Geeky I know, but I'm not artistic enough to come up with something on my own from scratch!



The graphics were drawn using Inkscape and laser printed onto an OHP transparency. I ran the transparency through the printer twice to ensure the black parts were completely opaque. You might need to play with the transparency settings in Inkscape for the colourful parts as LEDs are meant to shine through them. The SVG file is attached to this step.



I cut out a piece of 2mm clear acrylic sheet the same size as the graphic Using progressively finer sandpaper (800 grit was the finest used) the edge was sanded very smooth. Then using a butane pencil torch I flame polished it further. Be very careful! There is a fine line between polishing and burning the acrylic!



The final step was to laminate the transparency graphic to the acrylic. I took it to a sign maker for this. I figured a professional would do the best job. I was wrong. It wasn't how they would usually do something like this and it turned out less than perfect. If you want something done right, do it yourself! It's good enough for now but I'll have a go at fixing it at a later time.



