Lego NXT CNC Machine is Almost Complete!

After a couple hours of hardcore lego-building, the CNC machine is almost done. A few more rails, guides, and frames need to be added to improve the machine's overall performance. The video above shows what it can do right now. Currently, it can draw an almost-perfect 90 degree angle!

Lego NXT CNC Machine to Help Build Circuits

Tonight, I began my next Lego project. This one, I have to say, is probably the hardest. This is because it's a 3 axis CNC machine. The sole purpose of this project is to help me make more circuit boards for projects. I also think it's pretty neat to have a Lego CNC machine laying around. Anyways, after about two hours of hardcore tinkering and building, here's the progress. Feel free to comment or to give any recommendations!

Custom PCB's, Plastics, and More!

Making robots at home is really enjoyable. What's even better is when you can custom make your own parts! So that's exactly what I've been working on. After a little research, I figured out how to make custom plastic parts and custom PCB's! For the plastic, I will use simple molds from nuts, bolts, and other items of that matter. I will then melt down some InstaMorph� plastic beads for the molds. For the PCB's, I will use the copper clad and ferric chloride method. Along with the drilling of course. For now, I have two PCB's made. These two, in fact, are for the official SimpleBot. Thanks for reading and I'll be updating you guys with photos of the progress.

SimpleBots, an Instructables eBook!

What's better than creating a simple and hassle-free robot at home? Well, to be honest, the answer lurks right at the instructables store! It's called the SimpleBots eBook by Randy Sarafan (User: Randofo). The book features twenty four simple, yet amazing robotics projects. Each project can be built right inside your own home too! Don't believe me? See for yourself at the instructables store!

image source: instructables.com

CNC Machine Enclosure Take Two

This week at the Tinker's Workshop I have been rethinking my original design for the CNC machine enclosure that I posted last week.  My first attempt at the design looked great but actually still needed a bunch of work to make it less expensive and be able to have some sound proofing built into it.  Here is what I came up with. 

The enclosure for my Solsylva CNC machine will be nothing more than a large four foot box with doors that open on all sides.  Only the front doors will have windows in them.  All other door will be solid with foam pyramid foam for sound reduction while the machine is in use.  The original design had no sound reduction foam in it so it looked good but did nothing to make it quieter to use.  All the doors will allow for easier cleaning and maintenance of the machine.

The base of the enclosure is made up of 2 x 4 lumber, 1/2 inch plywood, and four casters.  The original design had a slated base which still could be designed that way but with the plywood deck it was no more expensive and a lot faster to construct.  All good.  This platform will hold the PC tower and electronics (black box) that makes the CNC work.  With the base being as large as it is it will also be a nice place to store anything else that I will need for the CNC machine or for the shop itself.   The  one piece deck also will be easier to clean than a slatted floor too. 

This is what the front doors will look like from the inside of the enclosure.  The pyramid foam I found online from a  company named The Foam Factory.  It will cost around $42 for the 12" x 12" foam panels that will be needed in the project.

Here is the other door panels with all surfaces covered with the foam sound deadening panels.  The foam can either be glued in place or possibly set in using Velcro strips.  I will have to experiment with some scrap pieces before I decide which direction I will go with it.

Even the top of the enclosure will have foam sound deadening panels inserted into it.  I figured that this will  be worth the effort as anything that can be done to make the machine run quieter will be a plus on my nerves and on my neighbors should they be close enough to be listening in on what I am making at the time.  The top panel has small mounting blocks attached to it so that it can just be dropped into place on the top of the enclosure and it will be ready to go.  

  Now for the cost savings in the project.  I crunched the preliminary numbers on the cost of the enclosure and this is what I came up with .  The original design which looked pretty but would be noisy  to use would cost roughly $412 to build.  This did not include the cost for paint or varnish and misclanious hardware (eg..screws, bolts, nuts, etc.).  After reworking the design to make it the same size but with sound deadening foam to reduce the noise the cost was  came down to $264 to build.  The big cast savings was mainly due to the expense of all the Plexi-glass that the original design called for.  Pretty and expensive.... not a good match.  All the windows did was allow enough light into the machine so you could see what you were milling.  The new design will have electric lights built into it so all the windows will not be needed. 

  So with the new design I get an enclosure that is easier to build, less expensive (Savings of around $150), and quieter to use while running the CNC machine.  I think we have a winner!  Once I get all the drawings put together for the design I will have plans put up on the plans page here for anyone that also needs this enclosure for their CNC machine.  Stay tuned for further updates when I start putting this project together.  

Soldering fail

Our laser-cut pcbs were certainly quicker to make than using laser-etching (we converted the pcb image to vector and cut out from around the traces rather than using the laser to etch a rasterized bitmap image) and the ferric chloride made a great job of etching them.

But because the mask had been laser cut, the etched part of the board is very very narrow.
And this has made soldering rather difficult. The tiniest little movement of either iron or solder means it's really easy to create bridges across the tracks - even when using tons of flux

We made a right mess of soldering the pin-header connector too - ripping the traces from the pcb when removing the IDE ribbon cable we'd squashed on top of it. So it looks like we're going to need to re-think the pin header idea - and find a way of solder-masking the rest of the PCB to stop the iron from bridging the traces when too much solder is applied!

Contact etching pcbs with lasered paint mask

It's cold and wet and the nerd cupboard seems such a long way away, and we've a pcb here that needs etching. Making up a batch of ferric seems like a bad idea, and storing it in the house could be a pain. What to do?

On one of the instructables pages, someone suggested contact etching using a sponge: http://www.instructables.com/id/Sponge-Ferric-Chloride-Method-Etch-Circuit-Bo/

Apparently it needs only a tiny amount of ferric chloride, so we put about four or five crystals into a ceramic eggcup and added a few drops of hot water. With some hair-dye gloves on, and a bit of sponge, we set to work, rubbing the ferric all over the copper board.

We've actually no idea how quickly it etched. The board is a funny orange colour (rather than the usual green we normally use) so it was almost impossible to tell when all the copper between the traces had been removed - it looked the same to us even after ten minutes!

Thankfully, the car paint sticks to the board really really well, so you can afford to even be a little bit rough with the sponge and board - no fear of the mask flaking off like you sometimes get with press-n-peel. After about ten minutes of rubbing the board over, we thought we'd take the mask layer off and see if anything had happened. If not, we'd put contact etching down as a bad job and never try it again!

The end result was very impressive.

Note how the trace in the top left corner has been completely removed. This is where we put the laser on too high a power and wiped out all but the tiniest, thinnest trace. Perhaps we did over-etch the board with the ferric chloride after all!

Although it's more than likely that we'd damaged the copper. Before starting the etching, we noticed that in a few places the copper had actually bubbled up from the board, where we'd blasted it with a high-powered laser!

As you can see in the photo above, the actual copper itself is damaged where the power of the laser was too high. So as we've etched away the good part, the bad bits have just disintegrated too.

Overall the end result is very good. We're going to repeat the exercise again using green coloured copper clad board, so we can see exactly how quickly the contact etching process takes. And of course, this time make sure we're running the laser at the correct power! The only thing of slight concern is that the laser drawn lines are very very fine. There's still plenty of copper between and around the traces and pads. Whether or not this will affect soldering or make it more difficult, or more likely to bridge, we'll have to wait an see. First instincts tell us that lots of flux is going to be needed to solder these boards!

GoBotics.com, Your Online Source For Robotics Parts

Do you have any upcoming robot projects that require some extra parts? If so, visit GoBotics.com. GoBotics has over 50 products ranging from Arduino to bipedal platforms. I highly recommend that you visit their site when you're purchasing parts for your next big project!

Laser etching PCBs instead of CNC routing

Well, our last post created a bit of interest - although some of it was just asking for clarification: we're not really etching the PCB with the laser cutter - it's still a copper clad board and the laser cutter still can't cut through anything metallic. But what we are doing is painting a mask onto the copper board (Halford's own brand Matt Black car paint if you ask) and then using the laser cutter to etch around our traces, much like a PCB CNC router would do.

Some people have already used a laser cutter to "etch" the PCB mask. What this means is that the laser cutter "draws" a bitmap by passing the head quickly left-to-right, firing the laser to make up the image, one scan line at a time. This is a very accurate way to create images (and a great way of "drawing" PCBs) but it can be really slow.

We're using the laser cutter in "cut mode" - so our artwork needs to be made entirely from vectors, not a bitmap. Depending on your PCB software, this could be easy (export CNC router files as dxf/vector) or a little more involved (ExpressPCB doesn't have an export option - it's free software to encourage you to use an online fabricator, but you can "print" your designs to a virtual printer, CutePDF)

We took our PCB design and printed it to a PDF using CutePDF.
Then we opened it in Inkscrape and hacked it about a bit. Here's how:

Print the top copper layer in ExpressPCB to the CutePDF virtual printer. Enter a filename and a PDF magically appears. Open this PDF in Inkscape

Our PDF was made up of a number of different types of objects (shapes, paths, lines etc) but to begin with they were all grouped together as one complete, moveable object. So the first thing to do is select all and UnGroup.

We selected the background and put it on it's own layer (so it can be made visible/invisible as needed). We also coloured it a different colour so that we can tell which shapes are on which layer. The first thing to note is that all the (black) traces on our PCB have been drawn over the white outline shapes.

This step is optional, depending on whether you want drill hole markers in your pads. We selected every centre of every hole, cut it from the PCB, added a new layer and pasted-in-place the holes. We then coloured them yellow so that they could be easily identified as being on the "holes" layer (and not part of the PCB layer)

With the holes layer invisible, select a white section of the PCB. We want to remove all traces of the white parts of the PCB, leaving just the black traces.

From the Edit Menu, select Find and in the pop-up dialogue put #ffffff as the "style" to find. Note that #FFFFFF doesn't always work - keep to lower-case just to be sure! Make sure the tick box for "find in this layer" is selected (we don't want to go deleting anything else by accident!), then hit find and wait a little while. All the white parts on the PCB layer will eventually become selected. Hit the delete key on your keyboard.

Right, that's got rid of all the white. Select all the black PCB traces on this layer. They're a peculiar mix of shapes, strokes and fills. Select "convert-to-path" to make them all similar shape objects. This can take a while. Go and make a brew.

When the eggtimer finally disappears, all your selected shapes should be the same type, so now we can merge them all together. From the Path menu again, with all the black parts selected, choose "union" to join them all together. Go get yourself a biscuit to go with that brew. This might take a while.

Eventually you should end up with one solid black shape. The highlight marks around the object(s) should now highlight one single shape.

If you want your pads to include drill holes, turn the holes layer back on. All your holes should appear as yellow dots (or whatever colour you changed them to). With the entire black shape selected, hold down the shift key on the keyboard and select a yellow dot. From the Path menu, choose "difference". The hole should be cut out from the black shape:

The reason we changed the colour of our dots is so that we can see when they have actually been cut out of the PCB traces, and are not just sitting on top of them. Repeat this with all the holes on the board (it's repetitive but not actually that hard to do all the holes).

Now here's where the magic begins. With the entire black shape selected, right click on stroke settings in the bottom left corner of the screen. Select "swap fill and stroke"

Ta-da!

Now, remember that this board is currently designed for press-n-peel; when it's transferred, the image gets flipped. Because we're drawing the PCB directly onto the copper, it's important to remember to flip the entire image. So turn on the background layer, swap the fill and stroke to get just the outline, then select all and from the Path menu, Flip Horizontally

That's it. We're done. Phew!
Don't forget to save as a format that your laser cutter can handle (we use .dxf) - if you're using RetinaEngrave or other virtual printer port software, you can print directly from Inkscape to your laser.

Don't forget to turn up the speed on your laser, and turn down the power. You're only cutting through a very thin layer of paint, and the copper board underneath will cause the laser beam to scatter - so plenty of speed (though not too much to make the cutter vibrate as it's working) and as low power as you can get away with!

You can use exactly this same technique, saving the results as dxf, to create files to load into a CNC mill, to do direct PCB milling on any compatible CNC machine too!

Laser cutting PCBs

Laser cutting? That's right! We're not laser etching here, we're laser cutting!
We took our PCB design and using Inkscape converted all the strokes into paths. Then, joined all the paths together using the union tool (it took about 45 seconds for the computer to think about that one). Lastly, we swapped the fill (solid black) and the stroke (null) and set the stroke thickness to 0.1mm
The result was a complete outline of our PCB traces:

So why cutting and not etching?
We've already found out that the fastest speed we can run our laser at is about 50mm/sec. And etching a board up to 100mm high, at a precision of 0.1mm means about a thousand horizontal passes. And the board is over 100mm wide, so that's more than 2 seconds per pass, so about 2000 seconds to etch. That's getting on for half an hour to etch a single PCB!

But if we replace etching with cutting, we should be able to get a reasonable "etching" speed from the laser. There's one way to find out -

We sprayed some acrylic paint onto a copper clad board and left it to dry for about 20 mins before running it through the laser cutter. The result was encouraging (but ultimately not really very satisfactory!)

The entire board took just under 3 minutes, cutting at 4mA and 50mm/sec.

But there's something not right here - those are some pretty wobbly traces! As we watched the board cutting, sometimes we could see the still-wet paint closing back around an etched line, making some lines fuzzy and indistinct.

Steve suggested Halford's Matt Black car paint, to be applied in two thin coats (with a few minutes with a hairdryer between coats to help them dry more quickly) rather than one big thick splodgy coat. We did this and tried again

This time the result was quite a bit sharper. But some of the lines (and especially the pads around the SMT resistors) were still a bit wobbly. It seems that running the laser at full tilt introduces a bit of vibration as it's cutting (the laser does bang about a bit as it twists and turns so quickly around those tiny little pads!)

We tried a third time, running at almost half speed, 30mm/sec. The result was much better and hardly any wobble at all in the pads/traces. This final attempt gave us a board which looked like it would etch and give a pretty good result

The only thing is, we forgot that when you reduce the cutting speed, you don't need as much power! The first trace lasered is that big thick etch running along the bottom and left hand edge of the board. It took us a while to realise what was going on, and we had to reduce the power down from about 4mA to 2mA to get a nice clean cut.

A quick wipe of the board after it was finished, with a wet cloth, and the tracks are all nice and shiny and clear of debris, ready for etching. It's getting rather late here now, so that'll have to wait until the morning!
Here's hoping it etches ok (and that we got our cutting depth right and everything still lines up...)

Spring Is Coming..... Time For A New CNC Project

  After several weeks of putting up with even more cold winter weather, shoveling more snow, the ever present tax man, and hassles with my home loan company I am finally getting back to getting another post out about a new project that again is long over due. Life is just to short to not have fun and so I hopefully will have better times ahead with this project and other projects that I have planned.  

  This project that I have been designing will involve making an enclosure for my CNC machine in the workshop.  I have used the machine in the old Tinker's Workshop with some great projects but have always had to hassle with the cleanup of the machine afterwards.  The CNC machine is a great tool to have in the shop but it tends to throw dust and chips of material everywhere while it is doing it's thing.  This got to be old really quick but with the old shop I was not able to make an enclosure for it simple because it would not fit into such a small space.   The new Tinker's Workshop is more than twice the size of the old shop so this is not a problem.  

  I have been spending a lot of time on my computer designing the enclosure for the CNC machine and still have a ways to go before I can start construction.  Lots of drawings still need to be created of  all the parts that go into the enclosure.  So for the time being at least I can show you what I have in mind for this project.

The enclosure for the machine is quite large as you can see from this computer image.  It is four feet square and stands six foot two inches tall!  This is a big enclosure to be sure.  The base is made out of 2 x 4 lumber and 1 x 4's for the base platform. 

In this image you can see the CNC machine inside the enclosure with the two front doors opened.  The sides of the enclosure will open up in the same way that the front doors do so that cleaning or maintenance of the CNC machine can be done easier.  All of the panels that make up the doors are exactly alike so it's just a matter of duplicating the parts for eight door panels over and over again until you have all that you will need.  The back panels for the enclosure will not need to be able to open up but could be just the same.  It might be a good idea should I need to replace the belt that drives the two side shafts that run the gantry on the X-Axis of the CNC machine.  It would be easy enough to allow for this and the cost is just a couple dollars more to add this feature. 

The big expense of the enclosure is not the wood to make it but rather the lexan (plexi-glass) windows for the project.  I priced out the cost for the twelve lexan 1/8th inch windows and I am looking at around $250 just for this part of the project.  Expensive to say the least.  Unless I can find a cheaper price or something else that will fill the bill I have no other choice but to go with this material. I suspect that the entire enclosure will run close to $350 once it is completed.  Not a cheap piece to make due to the cost of the windows.  But like anything else in the long run the CNC machine will be safer to run and easier to clean because of the enclosure.  Hopefully it will also cut down on some of the noise of the CNC machine makes while running.  I will have to see how my budget looks when I finally get the drawings for the enclosure completed.  Hopefully by then my old home will be sold and that will free up my cash flow once again for this project.  In the mean time it does not cost me anything to at least get the drawings ready for the project so when I can find the cash to put this big box together I can tear into it without delay.  I'll post more about this project once I start putting it all together. 

Back to a modular pcb-based board game

Having tried a non-pcb based board, and found it too fiddly, we're now re-visiting the idea of a pcb-based module for our board game. But we need to address some of the issues that made us think abandoning it was the right approach.

The first thing is that a 7-hex module is a great design, but only for a single module! When you try to put a few of those shapes together, you end up either with big gaps in the tessellating pattern or end up with lots of "spare" squares left over, because of the way the pieces fit together.

Basically, when you put multiple 7-hex segments together, the tessellating "direction" isn't regular:

The "direction" of tessellation is peculiar - neither upwards nor across, but in a not-quite-diagonal direction. This is the first thing we need to address. Ideally we want our modules to line up either horizontally or vertially. But how to achieve this? By simply adding another three squares...

If we want to make a roughly rectangular board game from these modules, we still get a few unused left over squares, but not nearly as many as we'd get if we made the same board layout from 7-hex segments. Plus, the "direction of tessellation" is running across the board. A much more satisfactory layout!

10-piece-hex module for digital board game

We haven't yet made up one of these boards to try out, but the basic principle is this:

Each board uses two shift registers. The first 5 bits on each register are used to control the leds on the module; the input serial line goes into one shift register and the output from this goes into the serial-in on the next shift register. The output from the second shift register goes back to the connector to allow data to be passed on to the (serial-in on the) next module in the board.

The buttons still use the resistor ladder approach. Since our other design, using a parallel to serial shift-register but with input buttons (instead of hall sensors) would still require pull up resistors on the inputs, we figured we'd keep the resistors and just lose the PISO shift registers. The downside to this approach is that each module must have it's own analogue input on the host micrcontroller. Luckily, we've some Microchip samples coming of PICs with a massive 32 analogue inputs on them. We might yet still need to use two of these together, in which case things may get a little more complex, but for now we're going to stick with this analogue/variable voltage approach for testing for input.

Now - why ten squares? Isn't it a bit wasteful?
Well it is, but here's why we're not worried:

Firstly, a 7-segment approach is wasteful. Only using 7 bits of a shift register rather than the full eight. In this arrangement we're still being wasteful, but now using 5 bits per shift register, instead of the full 8. We did consider expanding the board again, making it 15 squares but decided against it. Why?

A 15 square module would be physically very large. Etching such a large board could prove to be a problem. In fact, just getting the press-n-peel right on something so big could be a nightmare!
But also, we're sticking with 10 because it allows the same design to be used for actual square squares in future, not just hexes. A grid of 3x3 squares could be accommodated using the same techniques (only using 4 bits of one register and 5 bits of the other). Taking it a step further, a module of 4x4 squares could also be made, using all 8 bits of each shift register.

But a bit like avoiding a 15-square module for our hexes, going to a 4x4 grid of squares might cause problems on the analogue read, depending on the resolution of the host micro. A ladder of more than 10 resistors could have lots of cross-over, depending on the accuracy of the resistors in the ladder.

So we figured 10 is a nice compromise. It's not as efficient as using 15 hexes in a module, it does waste a few bits on the shift registers, but it does mean our input resistor ladder has only 10 different points to ground, making each band between inputs that little bit wider, and making it a bit more robust.

So about the only thing left to do is actually make one of these boards up and see if they actually work!

Resistor ladder for digital board game

Having decided to scrap making modules and a pcb-based board game, at one of the open nights at BuildBrighton we managed to put together a simple test piece for our game. It's still a 7-hex module whereas the final board will be 12 by 24 or something, but we're just trying out the idea of "dead-bugging" our design - soldering the parts together with bits of wire rather than mounting onto a PCB.
The result was..... interesting:

The buttons were held in place with hot glue. That in itself makes putting this thing together quite tricky - and there are only 7 playing squares here - the final board will have nearly 400!
Dabbing the wires onto the buttons was easy enough, but sometimes, when adding a wire and a resistor, one would pop off while the solder was still hot. Very frustrating! Because of the hot glue, only one of each pair of terminals was available to solder to.

From the front you'd never know what a mess it was at the back. But gluing the buttons and routing all the wires is a bit fiddly. It's almost like we could do with some kind of board that we could mount the buttons onto, to hold them in place, and then perhaps run the wires on the underside, rather than the same side as the buttons....

Almost like some kind of PCB, but with the buttons on one side and everything else on the other....in fact, a pcb with through hole buttons, rather than surface mount ones would be just the thing! (is this starting to sound familiar?)

Real Steal in Real Life

Tonight, the SyFy channel's Robot Combat League show will air. Unlike BattleBots, Robot Combat League features robots that can really relate to Real Steal. For example, the show consists of multiple teams, each team has a different humanoid robot, and they battle to the death. In addition, each robot that wins a battle against another robot advances in the overall tournament. If you're interested in viewing a previous episode, then watch the video above!

SimpleBotics forums!

SimpleBotics

Lego robot is able to fold and throw paper airplanes!

Folding airplanes can be pretty tricky. Well, that's not the case with this Lego robot! Constructed out of two NXT kits, this Lego robot is able to fold and throw paper airplanes. Don't believe me? Check out the video above, and have a great weekend!

Brain-Dead Robots Prove They Can Swarm Together

   

What has no brain, no computer, but can swarm? The answer is simply a bristle bot. Just recently, roboticists at Harvard discovered that even brainless bristlebots are able to swarm and form groups. The experiment consisted of a small area and a bucket-load of bristle bots. Right away the robots started to swarm together in a corner of the area.

You may be wondering, how does this swarming even occur? Well, my guess is that each robot just keeps bouncing off each other. Take the small area these bots were placed in for example. Since the robots were packed together closely, then they just kept running into each other. This process of bumping and running into each other was just repeated over and over again. To sum this all up, nothing really scientific or extraordinary took place. Even so, the video of the swarming robots is still entertaining to watch!



Source: automaton blog and special thanks to evil mad scientist labs.

Testing clicky buttons for digital board game

Although our buttons aren't soldered up yet and are only held in place with tape, we found out last night that the height of the button head is quite important for our board game to work.

We dropped the hex playing squares into place, and some buttons clicked fine while some didn't. There wasn't much difference (none that was immediately visible) between the two. Except one must have been slightly higher than the other. Luckily that could easily be corrected by adding a small piece of card on top of the non-responsive button. It's incredible that the thickness of a piece of card could be the difference between a button working or not!

A quick trip to Brighton Plastics on Boundary Road in Portslade (for some clear 3mm acrylic), 20 minutes drawing shapes in Inkscape and 10 minutes on the laser and we've a new prototype to try out!

 (this is the base layer - with holes for the buttons and LEDs to be mounted from underneath)

(this top layer will be cut from clear acrylic and the outer part glued to the base)

Instead of placing our hexes exactly side-by-side, we're cutting them out, leaving a surrounding bit of plastic. Although this is make from clear acrylic at the minute, once assembled, we'll be painting the whole base a single, solid (black) colour. Doing it this way not only saves acrylic, but also ensures that the hex pieces will fit back "inside" the honeycomb surround!

While Steve will probably go ape about us using superglue instead of contact adhesive or some polystyrene cement, we just wanted to see what it would look like so grabbed the first glue that came to hand!

The hexes give a satisfying faint click as each one is pressed. Nothing distracting, barely audible, but enough for you to register that the button has actually pressed down.

The solder tags on the buttons are all on the back of the board now, so there's no need to worry about ugly wires getting in the way (they can just be taped to the back of the board, then the whole thing mounted on a nice base).

At the minute, the hexes are just "floating" inside the honeycomb frame. Tip the board and they all just fall out! Steve suggested using buttons with a taller head on them and putting a few dots of funky foam under each one. By using dots instead of a continuous shape, the hexes can easily be pressed down - and they give an interesting effect to the board: each playing square would now be raised above the rest of the board

We could glue the hexes to the foam and have the foam stuck to the base so none of the squares come loose when the board is picked up and moved around. The only thing is we'd have to change the way we were planning on lighting up the playing squares:

Originally we planned on covering one side of the clear acrylic with a sticker, and using the laser cutter to take out a thin border around the edge of each playing square. But putting bits of funky foam in three of the six "corners" means we'll have to change our engraving pattern - otherwise the foam will get in the way of the light when a square is supposed to be lit up.

The effect isn't quite what we first planned, but is still a reasonable finish. With the correct colour scheme and sticker effect (they don't have to be plain black, they could be textured or slightly hologram-effect) these might actually look pretty cool!

Terminator Hand is Able to Tie Shoe Laces, Leaves Real Hands Behind

For too long, amputees have had to use primitive hooks and limbs that attach to their arms or nubs. With new technology, however, that will all change. So far, these prosthetic and robotic arms have been able to perform simple, mundane tasks. As opposed to those tasks. Special robotic arms, as opposed to the other ones, can now tie shoe laces. This goes to show how dexterous these arms and hands really are. Even later on as new technology is introduced, these arms will just keep advancing until they match the human hand. Perhaps they'll surpass the human hand in the near future. Thanks for reading and check out the video above to see it in action.

Funky foam isn't so funky

Funky foam is nice and soft and squidgy and quite flexible. But cut it into thin shapes, and the laser makes it go quite brittle and hard.

Plus it's only soft when you push it in one spot. When I mounted a hex onto this foam and tried to depress the entire hex shape downwards, the funky foam proved to be quite resilient! So, as is often the case when prototyping new ideas, it's back to the drawing board.

It's also time to consider the electronics that go under the playing squares too - funky foam is just under 2mm thick. Whatever we use in its place also has to work with the electronic components (push button/led). In our first example, the components sat under the playing piece, which sat on top of the funky foam. By pressing the square down and squashing the funky foam, the push button underneath could be pressed

But in practice, pressing against the foam was actually quite hard work. So now we're thinking of allowing the hex to be ever-so-slightly raised by the push button underneath, with a supporting "honeycomb" structure around each one.

Resting a button between two pieces of 3mm acrylic and we can see that only the button part stands slightly proud. If we were to use 6x6x4 tactile push buttons, and mount our pushbuttons from the underside of the playing board, we'd have a raised area of about 1mm to activate each playing square.

A hole is cut in the 3mm acrylic/mdf playing base and the pushbutton mounted from underneath (this also gives us the advantage of being able to solder to the underside of the board and hide all those nasty blobs of solder!)

 When pushed through, only the push-button part is raised. Over this, we place our hex cut-out shape

And place the playing square on top, simply floating on top of the push button. Each playing square should end up raised by 1mm. They may be fixed to the push button with a dab of glue (being careful not to glue the push button into a fixed position!) or simply left floating.

(Each playing square would also be engraved to allow the light from the LED underneath to shine through when lit but this has not been drawn here.)