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This post details the painting and assembly stage of my Noise-o-meter. This was probably the most time-consuming stage but also the most rewarding.

In this section, the materials I used were:

Step 1

PT3-STEP1

I stripped down the noise-o-meter leaving just the awkward parts in place, took it outside and sanded down the edges then started to paint on the white undercoat. I bought white paint, which was slightly glossy but maybe a matt white would have been better. In all I gave it about 3 coats.

Step 2

PT3-STEP2

I printed out the templates for each of the red, amber and green zones but in reverse and directly onto the backing of Frisket masking film. I suppose I could have printed onto paper then traced it through the film but I thought I’d get a more precise cut by printing directly on the backing of the film. In doing it this way, I had to reverse the design taking into account the adhesive side of the film.

Once printed I cut them out with a sharp scalpel knife leaving an inner and outer part, the outer part was then stuck in place and the inner part discarded, except for the counters (the part enclosed by the letter’s formation) which I then fixed as necessary. The beauty of the Frisket film is that it maintains its adhesion despite repeated repositioning – which I had to do in order to get it exactly right.

Step 3

PT3-STEP3

Before applying the paint I had to mask the surrounding areas – I used masking paper for this. I then took it to the shed (a well ventilated area (with door open) but sheltered from the wind) put on my dust mask and goggles and began spraying. I took each section in turn, masking the others as I went. I did around 3 coats for each zone, a light dusting to start with, to prevent the paint running; a further coat so no white showed through; then a final coat, ensuring it was all even. I used Kobra paint which was fast drying; I left around 10-15 between coats. The paint, however, is quite potent – so the dust mask is a MUST and doing it in short bursts, followed by a breather in the fresh air outside, is strongly advised.

Step 4

PT3-STEP4

This step is where all the preparation and work of the previous steps pay off. This was a tense moment: I left a lot to chance with the Frisket film having only tested it on a small piece beforehand. I was worried the paint may bleed through – especially considering the sponge roller I had used to apply the white undercoat had left a slightly bumpy surface. However, as you can see from the images, the lines are as crisp as if I’d used a marker pen and ruler. I’m really happy with the results.

Step 5

PT3-STEP5

The final bit of masking and spraying now. Using Illustrator and an A3 printer again, I printed out the zones with an equal white border around their perimeter. The Frisket film comes in a long roll so I could cover the length of all 3 zones in one go. Again I positioned this in place, using a ruler to make sure it was all even then masked the inside part with masking paper (tucking all wires in). In the photo it looks like I haven’t masked properly as you can see the zones showing through – this is indeed masked, the Frisket masking film is clear so you just can’t see it in that image.

Finally, having waited 20-30mins I peeled away the mask to reveal a pleasingly accurate white border.

Step 6

PT3-STEP6

Finally the assembly part. This is where it all comes together. I screwed everything back in place, cut the jumper wires to length and crimped their ends with Dupont connectors. For protection, and to improve the look, I bought a transparent case to house the Arduino, then for portability I attached a 9v battery holder. All done!

Image Gallery

Click an image to enlarge

Here is a video testing the increments.

May 4th, 2016

Posted In: Arduino, Classroom, Computer Science, computing

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