Sunday, 17 November 2013

Keypads for digital board game

We're both excited and a little disappointed with our current board game design.
Excited, because it's look more and more likely that we'll have a demonstrable, working design, that's easy to assemble (manufacture) and will create a far better "product" than we'd decided to settle on. But disappointed too - disappointed that we couldn't fulfil our original remit of manufacturing our board game(s) here in the UK.

A while back we had some PCBs made (in China for £8 each, best quote for an A4 PCB manufactured in the UK was a massive £120!). The idea behind using PCBs for our game board was because they are things we could either make ourselves, or have made locally (using screen printing and ferric chloride etching) while the upper playing surface would be printed and assembled here too. Each board section would have a fixed printed playing surface on the top.

Then we started thinking about making the top printed layer removeable - creating a "tray" to house the PCB with recessed edges with magnetic strips embedded in them. The top layer could then have magnetic strip around the edges and simply be placed over the PCB (and held in place by the magnetic strips).

But even making up just one or two board sections revealed this to be unsustainable for anything more than a niche product, selling a few tens of copies. Building a tray and assembling the push-to-make contacts from three separate layers was very fiddly. Also, we needed to affix small discs of steel under each "square" on the PCB, so that a playing piece with a magnet embedded in the base would be attracted to the playing surface. To date, the cheapest steel discs we found were one penny pieces!

So we've gone full circle and gone back to the very first design we had (and then discounted because it would be too expensive to have manufactured) which is  to use a keypad membrane. Here's our design for a simple keypad matrix:

We had some quotes for having the keypads manufactured in the UK.
The best quote from a UK-based company included the caveat that the membranes would actually be manufactured in "their" factory in China, but all design and discussion would go through the UK company. This seemed like a compromise rather than having everything made in the UK - but one we might live with, if it encouraged local business. Where the compromise fell down was on price.

Simply put, every one of the UK companies we approached wanted far too much - in both setup/tooling fees and per-unit price. Which is very disappointing - given that we really wanted to support and use UK-based businesses as much as possible.

However, once we got over the disappointment, we found a factory in China willing to make a small volume of samples for a couple of hundred pounds; this includes set-up and tooling and should we require any more in volume, the per-unit price is about one-tenth of the nearest UK supplier!

Which means that, once again we're taking a bit of a punt on an unknown supplier, but with the possibility of having access to lots of ready-built, easy-to-use keypad membranes for our digital board game.
And with a super-thin membrane (less than 0.6mm) the entire keypad could be stuck to a sheet of magnetic rubber (the stuff we were using for the copper-tape prototypes). If the dimensions of the keypad were slightly smaller (all round) than the magnetic board, then the top surface could be held in place easily too. The top printed surface just has magnetic strips on the underside, which fix straight onto the magnetic rubber mat. And, of course, there's no need to hot-glue pennies to the underside - the playing pieces would naturally be attracted to the magnetic playing surface.

Which means that once again, we're excited about receiving some components which will help us (finally) complete our electronic board game project.

Look out for more details - and, no doubt, a KickStarter project - in the near future ;-)