A project log for DrumKid: aleatoric drum machine

A lo-fi digital drum machine which uses randomness to create unpredictable beats. Runs on Arduino, with audio provided by the Mozzi library.

Matt BradshawMatt Bradshaw 09/20/2019 at 16:122 Comments

I showed my latest laser-cut plywood prototypes to a carpenter friend of mine, since I wasn't sure how to darken the wood to fit the aesthetic I was aiming for. After exploring a few options with him, I decided that using wood is perhaps more trouble than it's worth at this stage. While I would prefer to limit the amount of plastic I use, for environmental reasons, I think that perhaps it's justified in this case: it will probably be more hard-wearing, and I'm not using a huge quantity. Since I will be making DrumKid in relatively small batches myself, rather than mass-producing it, I can always re-evaluate this decision in the future.

With this decision made, I've been using my (not very advanced) image-editing skills to try and get an idea of what the first batch of units should look like. I can independently vary the following:

I already know what an all-black design with white LEDs looks like:

I'm pretty pleased with the monochrome design. It looks slicker than I imagined. However, the black solder mask actually looks slightly grey in real life, and the colouring has been slightly inconsistent between batches (the previous, unsuccessful PCB design was also ordered in black, but came out much darker). Also, my preference has always been for bright, even garish colours, and I'd like to include this part of my personality in the final design, if possible. With this in mind, I attempted to simulate a few different colour combinations.

First, I decided to try some bold, single-colour designs. Red, green, and blue are all available solder mask colours, so I wanted to see what it would look like to match the laser-cut parts and LED colours to the solder mask:

I quite like all three of these, but with a mild preference for red. I've also had trouble finding bright, pure-green LEDs in the past (they often look more yellow-green or fluorescent yellow), and I also worry that a green solder mask would look less stylish than another colour, since green is the traditional, "default" colour for circuit boards.

My next idea was inspired by my favourite Lego theme: M-Tron. For the unfamiliar, M-Tron was a successor to the classic Lego space theme, with a bold colour scheme of red, white, black, and fluorescent yellow (specifically transparent fluorescent yellow). Here's an example:

And here's my M-Tron-inspired DrumKid mock-up:

I really like this colour combination. I could even use transparent fluorescent yellow plastic for the rear panel, showing the circuitry and giving the characteristic edge-glow effect of laser-cut coloured transparent plastic. Sadly, I can't really do the same with the front plastic section, because it would show the soldered leads of the components, which (in my opinion) are a lot less attractive than the components themselves.

I mocked up one other design, inspired by chunky Fisher Price tape recorders - I rather like the idea of using a "toy" aesthetic, because DrumKid fits into a category of toy-like electronic instruments that have become popular in the last few years (Teenage Engineering being the foremost proponents of this style). Here are a couple of images of Fisher Price tape recorders that inspired me:

And here's my "toy" DrumKid design:

In the UK, we have a brand of savoury spread called Marmite, whose slogan is "you either love it or you hate it", the idea being that its taste is so strong that you can't have a neutral opinion of it (for the record, I love it). The idea is pervasive enough that "Marmite" has entered the dictionary as a word to describe something inherently polarising. I feel like my colourful ideas are, perhaps, Marmite designs, and I'm torn about whether this is a good thing. I certainly don't want to create something that looks dull, but I'm also aware that the Hackaday Prize website contains some valuable advice from Brian Benchoff: "creating for more than yourself is a necessary part of this year's Hackaday Prize". Am I failing to do that if I choose one of my garish colour schemes? Or is it clever to make your product stand out, especially when the best "marketing" for musical instruments is when people notice a band using your instrument on stage?

In the future, I hope to offer a choice of colours when selling DrumKid - there could be a drop-down menu with the option to design your own colour scheme. For now though, I'm going to run my ideas past some of my more stylish, fashion-conscious friends before I make my final decision. The black design strikes me as dull, but the multi-coloured designs might be a step too far. Perhaps the all-red design is the answer.

Update: I had a good chat with an artist friend of mine about the various possible colour schemes. He, unprompted by me, also picked the all-red and red-and-fluorescent-yellow designs as the best ones, so I am pretty certain that I will order the next PCB in red, and may end up ordering two sets of laser-cut parts, one in red and one in fluorescent yellow.


whocares wrote 09/23/2019 at 18:49 point

I really like the black design...

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Matt Bradshaw wrote 09/23/2019 at 18:51 point

That's totally fair, I suspect you're not alone!

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