CastAR – Kickstarter!

Hey everyone!

So for the few of you who have been living in a dumpster recently, Jeri Ellsworth and Rick Johnson, have been developing one of (what I think is) the coolest advances in gaming of the 21st century! A new kind of Augmented Reality glasses, castAR!








If you want a much better explanation of what it is and how it works and what it is there are many places I can send you, chief of which kinda has to be their website. Aside from that, Jeri has a pretty amazing youtube channel, and did a great interview about it on the amp hour (another must if you are into electronics).

But if you insist on listening to me and not them, I shall give you as detailed explanation as I can with the limited knowledge of the technology I have.

Basically, in a normal augmented reality system (such as google glass), the light is projected from a pico projector directly into your eye through some kind of prism. And this is all well and good, except because they have no reference to the real world, so to get around focussing issues, they focus the picture at infinity! Now this creates a great picture, but it doesn’t half confuse your eyes, because they put it into context with the rest of the picture, and with context it being focussed at infinity doesn’t make any sense! This can cause some issues such as headaches and nausea when using such glasses.

So what’s so special about castAR that made me call it “one of the coolest advances in gaming of the 21st century”? Well it’s quite a simple change, that changes alot. Instead of projecting the light directly into your eyes, these glasses project it out, towards a special kind of surface called a retrorelective surface. This is a special kind of surface which reflects pretty much all light directly back at you, meaning you can project a picture out to this surface and see it brilliantly clearly without your eyes getting confused over where to focus, because it all makes sense to your eyes with the world around it! This surface can also be used with multiple glasses at once.

Not only does this eliminate nausea and headaches, but the team at castAR have put in IR leds to the retroreflective surface, giving the glasses a reference point with which to render images onto. Allowing complete 3D rendering that is not only locked to the surface, but also allows you to walk around the render and it give realistic views of the object from all angles. From what I understand this is achieved by having each of the IR leds to pulse at different frequencies which can be identified by the glasses and used as reference points.

Add to this the wand they have created with more IR leds, which allows the user to interact with this 3D world (In one example the wand was used to knock over a jenga tower) and you get an inclusive, non-painful, interactive, gaming system for as many people as you like.

CastAR Wand







So what’s not to like?

Go check out the kickstarter campaign running at the moment for the glasses! 

Thanks all! And thanks to Jeri and Rick for developing such a cool gaming system!

Blutooth Audio Link – Video!

Above is a video about my Bluetooth Audio Link board REV.1.

My revision 2 board is currently up on OSHPark, so go check that out!

Also if you have got a rev.1 board here are the instructions for making it work properly! Unfortunately there were some design changes needing to be made which I overlooked on rev.1. So here are the instructions:

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In response to Corey, who requested a parts list for BAL Rev.2. Below is the Parts List for the REV.2 board, as exported from eagle, hope this helps:

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Here is the schematic for the board:
BAL Schematic

VFD Tube Clock

Hey people!

So a while ago I bought an old Vacuum Florescent Display tube, and attempted to build my own controller for it. Well I’ll keep that story brief but it doesn’t need saying that I failed dramatically, and blew about £60 on it ($96).

But I didn’t give up and a couple of weeks ago I bought myself an awesome little board from OSHPark. Built by a user named ‘Awesomenesser’. Unfortunately I have no means of contacting this person but I would sincerely like to thank him/her for making this awesome little board.

Built by Awesomenesser

Built by Awesomenesser

The board itself uses a MAX6921AUI. Which is a VFD controller chip made by maxim integrated. This chip is absolutely awesome so if you are thinking of doing a VFD project really do check it out!

Unfortunately the board was supplied with no instructions so I sat down for a while and compared data-sheets until I had something that made sense. Now I don’t want you to have to do the same thing so I thought I’d do a little picture and you can see for yourself how it goes.

Max6921AWI Breakout Explained

Some of you who know a thing about VFD tubes will know they run at high voltages, between 30 and 80 gives you a good bright light (though make sure not to exceed the 76V rating on the chip). So you may be wondering how I generated this. To do this I used the HCJ-IPM-V5 DC-DC step up converter, I would highly recommend this solution for anyone wanting up to 30V DC, simply because it is SO easy and simple and still very cheap.

DC-DC Step Up Converter


I also used a DS1307+ chip, to keep the time, with a 32.768KhZ watch crystal and a simple 3V coin cell to keep it running when off. I used a really useful library called RTCDue to interface this chip with my Arduino Due, though I plan on eventually running it on an ATMega328PU, in which case I will use this DS1307+ library from Adafruit.



And finally I used the Arduino Due to run the show. My code is available on gitHub so take a look if you are looking to interface with the MAX6921 chip! The library I use is specifically for the arduino Due, but if you change that the code should work perfectly on any other arduino!


Bluetooth Audio Link

UPDATE: The BAL project has now been redesigned, check the BAL section on the header to see the changes!

Hey everyone,

So after successfully completing my RGB LED strip lights, I was at a loss for what project to embark on next. I wanted to make something a bit more flashy, and a bit more well built.

That is when I saw this video from Sparkfun, where they used an RN-52 Bluetooth module to stream audio directly from a phone into speakers. Now this on it's own is no real use to me, but streaming it to an audio jack where I could plug in headphones or plug it into my full speaker system at home? That's useful (and cool)!!!

The video:

So I went onto EagleCAD, and started designing, finally creating this lovely little board:

Bluetooth Music Link


The design is chiefly pretty much the same as the sparkfun circuit, but instead of streaming it out to speakers, it has an audio jack. It also has a DC power jack with an onboard 3.3V supply. The switch is used to switch it between programming mode and normal mode.

If you are interested in the schematic, that is here:

Bluetooth Audio Link Schematic

As of yet, whilst I am still prototyping it, most of the components are through-hole, but if you want to order the board to try it out, it is available from OSHPark (which is where I ordered mine from).

WARNING, on the silkscreen, the LED's are backwards, if you order it make sure you put them the other way!

If you wish to make a board professionally, I seriously recommend OSHPark! They have amazing quality, and amazing prices too, and if you are not fussed about waiting, free international shipping. They are also run by a pretty cool guy called Laen, who is great.

Cheers all,

Tom Cousins

Hakko Fx-888D Review Take 2

Hey everyone!

This is a re-write of my review of the Hakko Fx-888D review, thanks to some brilliant people giving me feedback on the EEV Blog Forum – link to thread here.

So recently I picked up a new Soldering Station: the Hakko Fx-888D. This soldering station is a more substantial and robust iron than the one I had been using previously and is priced at a nice £100 ($150), so it’s a good price for hobbyists!

Specifications: For it’s price, the Hakko boasts some impressive specs! It is a 26V 70W iron with temperature control between 200ºC and 480ºC. At idle temperature it has an accuracy of ±1ºC. It features a useful preset mode, and password protection functionality for if you need it. As well as being ESD (electro-static discharge) safe and isolated from the mains. The heat up-time is a handy 40-50 seconds (depending on the temp) and it’s thermal recovery is excellent.

In the box: For the £100 you get the iron, along with a T18-B tip, the main unit, the manual, a stand for the iron, a sponge, and some brass wool (both of which fit in the iron holder.

Ease of use: This is one of the easiest irons I have used yet. If you simply want to get it running just plug it in, plug the iron into the main unit, switch the switch on the side of the unit and you are away! In this mode, setting the temperature is simple, just hold down the ‘ENTER’ button until the first digit starts flashing, then use the ‘UP’ button to change the value, and the ‘ENTER’ button to move to the next digit. The other modes can be accessed by holding the ‘UP’ button whilst powering on, and using enter to select the mode.

Performance: Well as expected the iron performs exactly as the specs said it would, heating from room temperature (21ºC) to 380ºC in just 42 seconds. The real-time feedback of the temperature is extremely useful because you know exactly what temperature you are currently on. There is a small LED at the bottom of the display which tells you when the iron heater is on too. The iron feels comfortable and solid in your hand but the cable is nice and flexible giving you the manoeuvrability you need when soldering. The footprint of the unit and stand is nice and small leaving you plenty of room on your bench (well, unless your bench is as untidy as mine) for working in.

Conclusion: I found the user manual to be a bit unclear on changing modes, but this did not affect the iron’s usability considerably. I also found that the tip they included wasn’t the tip I personally would have chosen, as I do mostly though-hole work, but I managed to buy another tip for only £6 ($10) more. Aside from that the iron was well-built, easy to use, comfortable, and in my opinion a great buy!

I would highly recommend the Hakko Fx-888D to anyone looking for a sub £150 ($200) soldering station. It is excellent value for money and does everything I expected it to! I am thoroughly pleased with it.

Hakko Fx-888D Review

Hey everyone!

So I’ve been soldering on my old Soldering Iron (Antex C15), which, don’t get me wrong, is a lovely iron for it’s price, for a while. But I’ve been doing a lot of soldering recently and it wasn’t quite good enough. So I decided to upgrade to a slightly higher priced and more professional Soldering Station, the Hakko Fx-888D.

IMG_20130819_102436The Hakko's image in profile

I’ll start with some of the issues I had with the Antex, so we can compare them. First, the Antex had no temperature control, and although many people who have used a non-temperature controlled iron for a long time will say this doesn’t strictly matter, it makes a lot of difference to me. Secondly, the Antex is not isolated from the mains, and if you are not careful this can REALLY mess you up. Thirdly, it took a long time to heat up (about 4-5 minutes in my case) and if you just want to do something quickly, then this isn’t fun. Finally, it has a hefty cable connecting it to a mains plug which doesn’t flex very much, making it awkward to manoeuvre sometimes.

So how does the Hakko compare? Well, first off it does have temperature control. This can be useful in many cases, if you are often switching between leaded and unleaded solder this is a blessing, because they both should be used at different temperatures. And if you a switching a lot between soldering small components with a small thermal mass, and big beefy cables with a very high thermal mass this again can help a lot. There is nothing worse than trying to solder to a large thermal mass object with just a small 15W iron.

The Hakko's temp readout midway in heating up


Secondly, the Hakko Iron is not only isolated from the mains, but it is also ESD (Electrostatic Discharge) safe. ESD is a problem that can occur when humans, who build up a lot of static electricity, touch components, and the static is discharged through the component, sometimes breaking it. To avoid this the rubberised handle for the Iron is made of a special conductive rubber which itself is connected to ground, ensuring when you pick it up all the static electricity is discharged to ground making you ESD safe.

The size of the iron


Thirdly, and for me this has made the most difference, this iron is very quick at heating up (for me it takes about 45 seconds). This means if you want to quickly make a small alteration to a prototype it isn’t a hassle to wait for the iron to heat up and you can be done in 2 minutes.

Finally, the design of this iron is in my opinion superb! The unit itself doesn’t take up much space on the bench, and the UI is (mostly) simple and easy to use. The iron itself is comfortable to hold and easy to manoeuvre (the cable is nice and flexible and light) and the custom holder that comes with the iron is very convenient, having a place for a sponge and some brass wool to clean the iron tip (both supplied with the iron).

The iron holderThe Iron stand supplied with itSponge and brass wool to clean the tip

To say this iron is without flaws though would be a lie, for one, the manual supplied with the iron gives very poor instructions on how to change the modes. And the tip it is supplied with is a conical tip, which in my opinion isn’t the greatest tip type in the world. I bought myself a small chisel tip along with the iron which greatly improves the functionality of the iron as a whole.

If you are looking for a sub-£100 soldering station, I would highly recommend the Hakko fx-888D!

Tom Cousins


RGB LED Strip Room Lighting Build – Part 2

Hey there everyone!

So in part one I dealt with getting the strip hooked up to the MOSFETs and getting it fading through the colour Spectrum!

Now that is great and all, but I want to do MUCH more than that. My original plan was to have a controller module with some potentiometers and buttons, so that’s exactly what it’s going to have. I decided to build it all up on vero-board because it’s easy to prototype on vero, but you can use whatever you like! The schematic will be down below.

So I first hooked up my slide potentiometers, with pin 1 going to power, pin 3 going to ground, and pin 2 feeding into one of the analog pins on the Arduino Pro Mini (from Sparkfun, you should check them out!), I used pins A1, A2, and A3 for this, but you can use whichever you like. I then hooked up my buttons, with one half of the button going to ground, and one half going into some of the digital I/O pins on the Arduino (yet another brilliant OSHW company). I used pins 2, 3, and 4. I connected them to ground because in the code I will enable something called the internal pull-up resistors for those pins.

Pull-up and pull-down resistors prevent electro-magnetic waves in the air from inducing current in the wires and tricking the micro-controller into thinking the button has been pushed. A pull-down resistor is a large resistor value (usually 10K) that connect the pin to ground, so when any current is induced it goes straight to ground. However when you push the switch all but a little (because of the high resistor value) goes into the micro and registers as a logic high. A pull-up resistor works much the same but reversed, the resistor always connects the pin to positive voltage registering as a logic high, until you push the switch and connect it to ground, thus giving it a logic low. Seen as the Arduino Pro Mini has internal pull-up resistors I am using these so as to minimise the amount of external components I need.

I finally soldered in the MOSFETs according to my circuit diagram, and then added some terminal blocks for the connections to power and some headers for the connections to the strip. I added these in to make sure I could take it out once I had finished it, so I could hack it later on and update code and such.

The audio connection I made by getting a simple 3.5mm Jack cable and cutting the ends off, I stripped the two wires at each end and put one to the input, and one to the output of one of my speakers. I then attached the output one to ground on the controller and the input one to the Arduino. It works okay but at some point I might put in a low pass filter to get just the bass track, which will be easier for the system to react to.

Check out the photos below!

Tom Cousins

P.s. If you don’t know Jeremy Blum (who just got a job at Google – well done!!), check out his blog, and his youtube. He was pretty much my inspiration for starting this, so I thought I’d give him a mention!

P.p.s I got the inspiration for this project from one of the projects Adafruit (a really great company doing some really cool stuff!!!) have done. Check that out if you want to!! The link is here.

RGB LED Strip Room Lighting Build – Part 1

Hey there everyone!

So I recently ordered some RGB LED strips from e-Bay (sorry the link is for e-Bay UK, I’m a UK guy so!) and I’m planning on turning these into a lighting system for my bedroom at home. In this post I’m going to take you through how far I’ve got so far and I’ll probably finish it in the next post.

So I ordered the LED strips first (the LED strips are 5050 SMD RGB LED’s and I got the 60LED/m type. I had to make sure they were common anode. This is very important), planning to test them with some N-Channel MOSFET’s I had hanging around and just a simple 12V DC adapter to power them. And control it from my arduino due. So once I first got them I hooked them up with the 12V power supply going into the power and the FET’s sinking the line from each colour.

I really should have checked the power output of the DC adapter because the 0.3A it could provide got used up quickly! It screamed at me and, as Dave Jones from the EEVBlog would say, released the ‘magic smoke’. Not a good start. After this I checked the consumption rate of the LED’s and was surprised to say the least that these things gobble up a huge 6A! So I needed an alternative really.

My next build thought took me to an ATX computer power supply, so I went down to my local computer store and tried to see if they had any old ones in the back (this is one of the best tips I can give you!! Ask for the old stuff, and you get it cheap!) unfortunately they didn’t. So I went to my friend and asked if he knew anyone who had one, well, turns out he had one. It’s an old Dell N220P-00 220W power supply. I had a little bit of trouble getting it to run as outlined in the previous blog post, but eventually I got it running. After a small hiccup with mains voltage from a capacitor!

So now I could test the strips fully, I started by simply hard wiring the red, the green, and the blue individually, then did white to see how it looked. I was really impressed, these things are BRIGHT for £15 (Around $23).

So now I hooked them up to a micro-controller, I took the 5V line, the 12V line and the Gnd out of the power supply and hooked it up with the 5V line going to the micro-controller, the ground line connecting to both the micro’s ground and the ground after the mosfets (see schematic for mosfets) and the 12V line going into the RGB strip common anode.

For the micro-controller I used a Sparkfun Arduino Pro Mini, I really like this chip because it is small, inexpensive, and easy to embed in projects! The only disadvantage is that you have to also buy an FTDI adapter for it, but this is just a tradeoff for it’s size!

I programmed the chip (code available on GitHub) with the test code I wrote, this code simply changes through the spectrum of colours slowly!

I then cut the strip in two (there are special sections along it where you can cut it) and rejoined it with wire so it would run as two parallel tracks, and used phone cable to extend the wire at the end. I used phone cable because it is 4 wire inside, perfect for RGB strips, and it can easily be attached with clips to walls. It is also white which means it doesn’t stand out too much. I finally mounted the two strips in my room where I wanted them and turned them on.

The results so far are brilliant! I really like them!

In part 2 I will build the controller for them, so they do more than just fade! (Hopefully I can get them reacting to the music from my speaker system)

Tom Cousins

Link to part 2 here.

Getting an ATX power supply to run outside a PC

Hey everyone,

So I recently bought an old ATX power supply off a friend of mine, and it took me hours to get it running, so I thought I’d do a quick post to help you guys do it in future.

So first thing everyone will tell you is to ground the green wire to turn it on! And this is true, the green wire (or the DC_ON wire) is your main switch for the power supply. And when you ground it, this should turn the power supply on, but only after you do a load of other stuff!

Some power supply’s (like the Dell n220p-00 I have) have smaller thinner wires of the same colour as most of the positive outputs and ground. So you will have one for 5V, one for 12V, one for 3.3V and one for Gnd most likely. These are sense wires and they must be connected to the same rail as they are coloured with (red for 5V, yellow for 12V, orange for 3.3V, and black for Gnd), they sense the rail constantly to check for shorts on that rail or if the rail is somehow broken. This is a great advantage when you have it running, but if you don’t know about it then it is a pain to get running. The solution is to take each of these thin wires and solder it to an output wire of the same colour. Then ground the green wire and it should now turn on!

Some power supplies have multiple ground sense wires and some also have the sense wires the same thickness as the normal outputs, so if all yours are the same and it doesn’t work automatically, check where the wires go on the PCB. If it is an odd one out, it’s probably a sense wire.

Also some require a constant load on the 5V line! For this I used a 100R Power resistor (10W) between 5V and Gnd!

Be really careful when taking these things apart! Honest, even when they’re unplugged  you should let them sit for 2 days or so before messing with them. I made the mistake of assuming that because it was unplugged it was safe, boom, I shorted a capacitor and was across the room. Not fun.

Take care guys!

Tom Cousins


Getting into Electronics

Hey there everyone!

So, I’m presuming if you’re reading this you’re fairly new on the electronics scene, or you’re just wondering how easy it is to get into electronics nowadays? Well I’ll tell you simply — very.

In my opinion, electronics has never been quite so interactive and fun as now! And in all honestly, I feel privileged to be growing up and learning in such a great community and atmosphere. But let’s back up a little?? How to start?

Well if you’re serious, it’s going to require a little bit of investment, but honestly? I think that investment is TOTALLY 100% worth it. There are some amazing companies out there specifically tailoring for people joining the electronics world, companies like Little Bits (An electronics company who make magnetic “Snap Together” modules – Check them out!!!) or Arduino, which is an open-source company who build development boards around the ATMega series of micro-controllers from Atmel. In my experience, once I got my hands on an Arduino board, the possibilities just opened up for me, using the IDE that they provide you can go from a couple of components, a breadboard, and a blue thingimabob, to a fully working prototype in a matter of minutes. Plus there are some AWESOME tutorials for how to get started, how the Arduino works and how you code it out there, my personal favourite being Jeremy Blum’s great Arduino Tutorials. From there you can start to move up, as I have, to more complex designs and more interesting idea’s. That’s how I did it, and I would certainly recommend it.


You are the one who has to put in the work here, and you have to have the drive and interest to see it through.  It’s just like learning a new language or a musical instrument, you’re not going to learn it all overnight!! I get a surprising amount of people asking me things like “How did you learn all this?”, and the answer is surprisingly simple, I put in an inordinate amount of hours and I devoted myself to it.

So go out there and surf the net! Find your own favourites and learn in your own way! It doesn’t work if someone forces you into it, you have to do it yourself.

Good Luck!


My First Arduino running with an AXE133Y 16X2 OLED display!

My First Arduino running with an AXE133Y 16X2 OLED display!

P.s. If you want to look at some of my tutorials take a look at this page.