Author Archives: Chris Holden

Not even copper washers work

Steve came up with a great idea yesterday: copper washers!Copper is a number of times more conductive than stainless steel (or even zinc, as we’re not sure if any of our many different washers are electroplated steel) so it makes sense that copper wash… Continue reading

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Another almost success with the electronic board game

This board game designing is harder than you’d think. Not creating an actual game, just getting the mechanics of tracking pieces around a board with electronics. It’s proving quite difficult!Our inspired idea, using washers which drop into place and ar… Continue reading

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New method for creating board game sections

Another evening at BuildBrighton means another go on the laser cutter and another PCB/mdf combo for our new-style board game sections. Having spent a while designing the PCB so that it can be made from a single piece of single-sided copper board, (mean… Continue reading

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A new approach for New Year

Having decided that we need some steel parts in the construction of our board game sections, it was once again time to try out a new idea.This time we’ve tried to focus on easy-to-source materials, rather than trying to focus on the long-game and manuf… Continue reading

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And so the circle turns again

A while back, we thought we had a winning formula for our board game. It consisted of a rather messy arrangements of pennies stuck to a board, with a layer of copper tape stripes above it. Although it worked, constructing it was painful, so we tried using magnets over some copper clad board, to simplify the actual building of the board.

The problem with copper board, of course, is that it’s not magnetic, so we had to fix some thick steel bolts to the underside of the board in order to get the magnets to pull our top and bottom layers together.

Once this was working, we etched some massive double-sided PCBs to test the theory out with a “proper” circuit board.

This time, we tried using pennies instead of bolts on the underside of the board, to give the magnets something to pull onto.

We then had some professional PCBs manufactured, added our own separator layer and placed a printed sheet on the top.

The result? Because of the thickness of the PCB, we needed to use two pennies to provide enough steel, and a 3mm thick, 10mm magnet to get the contacts to close. This means that the cost of building each board has immediately gone up by 2×88 = £1.76, just in pennies (post-1992 pennies are still the cheapest source of round discs of steel we can find!). That wasn’t the problem. The problem was no-one is likely to want to stick massive thick 3mm magnets to the undersides of their treasured miniatures to use as playing pieces.

So we tried something else – getting custom keypad membranes manufactured. They took a while to arrive, but looked very promising when they did

The final keypad membranes have a tiny 0.125mm gap between the top and bottom layers – perfect for use with 1mm thick magnets…..

Unfortunately, because of the manufacturing process – and because they are designed to be pressed by a human finger, not a piece of plastic with a magnet on it – the vacuum between the layers means that they need quite a press to get the contacts to close. In fact, they need a piece of steel and a 2mm thick magnet to get the playing piece to register it’s position above any one square.
As part of the construction, using a custom membrane, we still have to introduce steel somewhere in or around the material that the keypad will be mounted onto (and still have the small matter of connecting the membrane to a PCB on the underside).

It’s becoming obvious that using steel (or a similar, ferrous/magnetic metal) in the construction needs to be given more consideration, and not just included as an afterthought. Which has brought us full circle right back to where we started – with small discs of steel being set into a rigid playing surface.

Now, if we’re going to the trouble of constructing each board section, instead of buying in parts from overseas (something that some of us were not always entirely comfortable with, given we have the expertise, if not the workspace – yet – to print and etch our own circuits) then perhaps it’s time to review the whole project. Back to the drawing board, as it were.

Instead of trying to build our entire board game system in one go, re-purposing the board sections for different board game styles and genres, maybe we should be looking less at the cost of production, and more on actually getting some production done and optimising to reduce costs from there. Instead of creating loads of the same board sections, then changing the way the software reads the boards, for different games, we’re going to focus on just one game – and then re-use the technology, but not necessarily the construction methods – for the others.

So we’re back to building a space-ship based shoot’em up: Laser Squad on a board game.
But since we’re moving away from having just a few large board sections, with different artwork on them for different games, to custom board game sections for each game…. why not go the whole hog and make different board game sections for the same game?
What about some kind of Laser Squad/Space Hulk mash-up?

Space Hulk had this great game mechanic – the boardgame was made from loads of smaller sections, which meant each game could be played out across a different spaceship. It was a simple idea, but one that worked (and still works) really well. Even with just a few different board sections, it’s possible to have a really interesting playing surface.

Here’s some preliminary sketches of how we might incorporate different board game sections into a Space Hulk/Laser Squad mash-up, that we’ve tentatively called Starship Raiders (ok, it’s only called that because it was the only spaceship themed URL we could get hold of, but it’s not a bad name!)

Our board game sections are

  1. 4×4 room with one exit
  2. 4-way corridor crossroads
  3. Single corridor section (all corridors will be two squares wide)
  4. 4×4 room with two exits
  5. 4×4 room with four exits
  6. Corridor right angled turn

One thing we need to consider is that not all board game sections will be able to connect on all sides.

If we consider using red for power, black for ground, green for rx and blue for tx, there are only so many ways we can lay out the connecting pins.
On the left and right hand edges, the pins need to be in the same order (so that two board edges can connect together). Likewise, the pins on the top and bottom of each piece need to be in the same order, for the same reason.

The problem comes when board sections are rotated (and is not immediately obvious from a piece which is symmetrical in more than one axis). Let’s consider connecting a room piece to a “crossroads”.

Connecting this way is fine – the connectors all line up. But what if we connect the room to the right hand edge of the crossroads piece?

Bzzzt! We’ve got a dead short!
So we need to make sure that our power and ground pins are on pins 1 and 3, so that when the board is flipped over and connected to an edge that it shouldn’t, these pins line up to 2 & 4 on the other board section, rendering them harmless.

If we continue adding board sections without correcting this problem first, it may lead to some pretty funky data being passed back and forth, but at least there’s no dead short threatening to kill our power supply (or worse still, damage the hardware that talks to the rest of the home network). From top-to-bottom (or left-to-right) our connectors read “pigo” – power, data in, ground, data out.

So our current thinking is that when a board section is first powered up (i.e. added to an existing, powered, board section) a one-off message is sent back to the host controller, telling it the ID of the piece just connected. On receiving this message, the host app can play a wav sample to let the user know that their board section has been accepted. If you connect a board piece and – after a short delay – hear a ting, ting, ting success message, you know you’ve connected it the right way round. If, however, you connect a piece and there’s silence after a few seconds, the new board section hasn’t been connected the right way (because it’s either not powered up, or – if by some miracle it takes power from the data lines of the previous section – it’s not able to send the “connect ok” message back to the host). Or, there’s always the possibility that the code is buggy or something’s just gone wrong ;-)

With all this in mind, it’s time to make some PCBs and try this whole new fangled way of working out!
We’re thinking of using “penny washers” for our steel discs. These are typically 25mm in diameter and 1.5mm thick, with a hole for an M5, M6 or M7 bolt.
If we use a pin in the centre of the hole, our top layer doesn’t need to connect to anything on the board – it can just be a series of conductive dots which, when pressed, cause the pin in the centre of the washer to connect to the ring around it. By powering each row (or column) of washers one at a time, and reading the data inputs from the pins, we should be able to tell which washers have a magnet above them (since the signal from the washer will be conducted through the pin, back to the mcu).

Here’s a design for a 6×2 corridor section (for some reason, we added some LEDs along the edges of the corridor, controllable by an HC595 shift register – this probably won’t make it into the final version, but it seemed like a bit of fun)

As this PCB is quite large (160mm x 70mm) it’s going to be a bit of a nightmare to press-n-peel (the old blule paper doesn’t like transferring large areas of filled toner as it tends to smudge a bit during transfer) so this will have to wait until the next BuildBrighton session, where we’ll do some PCB mask etching on the laser cutter.

Updates and debriefing (on whether it was a success, or another miserable failure) will be posted soon! Continue reading

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Audio playing toy with a PIC 16F1825

While we’re waiting for our keypad membranes to arrive, and while a few other projects are waiting for parts (we really need some 5v zeners before trying our phone dialler in a live telephone point) last night’s BuildBrighton Open Night was all about l… Continue reading

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Micro guitar amp mixer

It’s been nearly three weeks since we went out to Berlin. The Arduino workshops were a success and from a group of about eight people, we reckon at least three (maybe four) are already well on their way to becoming electronics and Arduino aficionados!S… Continue reading

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Running courses with an Arduino Mini Pro in Berlin

Once again, some of the nerds are off to Berlin.
This time, we’re going to be running an introduction to electronics course, and getting people started with Arduino and microcontrollers in general. So the first thing we needed, of course, was some components and some Arduinos!

These Arduino clones use the AtMega328 mcu on a small form-factor board, for plugging into a breadboard. So they may not be ideal if you want to use one of the many existing “shields” for the original Arduino. But as a starter board, they’re perfect – and super-cheap too. At the time of writing, an Arduino Pro Mini could be had for less than two of your finest English Pounds.

For £2 the board doesn’t have a usb-to-serial adapter: you’re expected to provide this yourself for programming or running a serial monitor. But another quick flick through eBay, and there are USB-to-serial converters for less than a quid!

(sometimes searching for “usb ttl” returns cheaper alternatives that might otherwise have been missed, if searching for just “usb serial” or even “usb uart”)

All in all, we managed to get a load of Arduinos up and working for about £3 each. Not bad at all – especially when having to buy in bulk and pay for everything up front (people at the workshop will pay-on-the-day, so anything to keep the initial outlay down is a great help).

But it’s not all plain sailing. The boards arrived yesterday, but it’s not simply a case of plugging everything together and it all just works. For £3 an Ardunio, that would just be too easy! The first thing is, if you’re using Windows 8, the built-in drivers for a non-FTDI based usb-to-serial converter may not work.
Ours show up as a Prolific USB-to-serial COM port (most converters use some kind of virtual com port)

When we first plugged the device into a Windows 8 machine, it said that the driver was up to date, but the device could not start. This was a little puzzling, so we did some digging about. No-one seems sure about why the newer drivers won’t work with Windows 8, but the workaround is to download and use older drivers. We used the driver version 3.3.2
Great – now the board was installed and working. We fired up the Arduino IDE and the COM port was indeed recognised and we were able to select it as the target port for our programmer
Our boards are Arduino Pro Mini, running off 5v with a 16Mhz crystal. There are other variants of these boards available online, so make sure to select the right version of board!
But the fun hadn’t ended yet.
With the usb-to-serial device working, and the Arduino connect correctly (tx-to-rx from the usb-to-serial device to the Arduino Pro Mini board) we tried to dump an amended “blink” example to the board, just to check everything was working. It seemed to spend a long time uploading the binary – and then stopped with a failed error message:
A bit like getting stuck on a crossword clue, it took a bit of messing about and trying different things before we gave up and asked Mr Google for the answer. Apparently, the trick with these little boards is to manually hold the device in reset before attempting to program. 
So to get the “sketch” onto the board, hold down the reset button on the Arduino Pro Mini board (they all come with a small pushbutton on them somewhere) and while the reset button is still pressed, hit the upload button in the Arduino IDE.
The IDE will compile the code – keep the reset button pressed. Once the code is compiled, and the IDE reports the message “Uploading….” release the reset button. The upload continues and (hopefully) the message will return to “Done uploading” without the crude avrdude error message in orange! Hopefully…. it did for us!

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Keypad membrane manufacture

Just had an email through from the factory in China with a couple of photos showing our electronic board game keypad membranes being dry-fit for testingIn the end we had to provide the artwork (which we were a bit nervous about – these guys are the key… Continue reading

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Telephone dialler (DTMF tone generator using PIC 16F1825) for dementia sufferers

A lady called Pauline popped into BuildBrighton the other day and asked for help with a particular project. Now, quite often, we’re all busy with our own projects and very often the odd chancer turns up, with promises of millions of pounds of venture c… Continue reading

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