Unknown Domain

Parts: Plug

The last thing I looked at was the power cord, but equally important is the plug and it’s fittings, strain relief, etc…

Unfortunately power plugs don’t seem to be so much of a fashion statement as the fancy chrome plates sockets, and fabric sheathed cables that adorn them. This means that most plugs are just ugly plugs, but there are a few clever ones out there which a maker might choose over the standard cheapie.

Most plugs in UK high street shops seem to be manufactured by Masterplug, so there is a rather limited and duplicated set of products from various suppliers including, Homebase, B&Q, Screwfix, and Robert Dyas.


Masterplug have three ranges of standard UK three pin plug, the first is their heavy duty model (HDPT13), which is available in black (HDPT13B), white (HDPT13W) and orange (HDPT13O). It is 13 amp rated and as the picture shows, it has a chunky rubberised finish with good side grips. This retails for £3.



Next up is their rather ordinary looking PT13 model which as you can see comes in black (PT13B), or indeed white (PT13W), which seems to be the most common in the shops and retails for £2, it has a glossy finish and is very plain and cheap looking.


The last in their product line is an interesting one as it has a special grip at the back to make it easier to remove. PT13H comes in white only (PT13HW) and has the same cheap nasty glossy finish as the PT13 but has a ‘ring pull’ to make it easier for those with difficulties gripping to pull it out, especially useful if the pins get bent as can happen sometimes. It retails for about £2 also.

The Other End

At the other end of the cord will be a connector as well, as there is no cord retract on this model it makes sense to make it easier to put the cable away at the end of use, or to help routing it around things for a more permanent installation in a makers shed. What we commonly think of as a ‘kettle lead/cord’ actually has a far more boring, but technical name… ‘IEC 60320 C15’.

To break down what IEC 60320 C15 is I did a bit of research… IEC stands for ‘International Electrotechnical Commission’ who are a body who deal with the specification of international electrical standards to make things more compatible. IEC 60320 is one such standard, specifically it is for a non-locking electrical power coupler, i.e. a socket and plug for powering devices. The specification is specifically designed for home and office use, as it specifies sockets for up to 250V @ 20amps (in some cases).

Within the IEC 60320 standard are a number of different types of connector for different purposes, from your traditional 2 pin electric shaver C1/C2 coupling rated for a mear 0.2 amps, a three pin cloverleaf shaped laptop power supply C5/C6 coupling, and the widely used figure-8 connector on a radio called C7/C8. Through to the even more common C13/C14 connector used on a home computer and the confusingly similar C15/C16 connector used on heated appliances  especially older kettles, where the difference is simply the maximum temperature the cable assembly is rated for, and a small notch to prevent a ordinary C13 plug being coupled with a C16 socket where the heat could melt the plastic of the C13 plug leaving exposed live wiring, or shorting out whilst powered. At the top end there is even a C19/C20 used on the back of a Mac Pro and other high end computers mainly, which is used for high power appliances where a traditional C13/C14 assembly wouldn’t support the current requirement.

There is an interesting part of this IEC 60320 standard which is that C17/C18 are actually two pin versions of the common kettle cord, and among the many places such as Xbox’s they are commonly found on vacuum cleaners. Indeed some commercial/industrial use machines have this, and vacuum cleaners commonly aren’t earthed as they produce so much electrical noise and have no exposed metal surfaces to ground. The C17/C18 coupling isn’t easy to get hold of and is pin compatible with a C13 cord, but not the other way C14 and C18 because this would leave the earthed product unearthed.

In the spirit of this project I will use the most commonly available and accessible coupling, the C13/C14 pair, there are a few varians of the C13 plug, not least straight, horizontal right-angle, and vertical right-angle. You can also buy panel mounting sockets too.


Panel mounting socket

Straight plug

Straight plug


Horizontal right-angle plug

Vertical right-angle plug

Vertical right-angle plug

It would seem logical to make use of the vertical right angle plug, or horizontal right angle plug in this design to avoid it being pulled out by accident, the cable could come down along the body of the vacuum cleaner and through a metal retention clip like below:

Retention clip

Retention clip

Parts: Power cord


I had thought that it would be good to have a cable retract and that may yet still happen however the main focus is the vacuum cleaner, the power cord rewind is secondary. I would also quite like to investigate an audible alert mechanism for when the retract is pulled out to its limit as the yellow and red tape indicators aren’t particularly obvious.

I would still like to use an attractive cord, indeed the whole point of making your own vacuum is you can make it your way. I am looking at using a fabric sheathed cord. I have looked at samples from FabricCable and I quite like the black and white striped cord, however their products are apparently only rated for lighting appliances so I will have to speak to an electrician about whether I can use it for a vacuum cleaner safely.


UPDATE: Looks like they do sell a power cord for appliances but it’s a number of times more expensive here.

Where is it all going wrong?

logosWoolworths, JJB, Blockbuster, Comet, Jessops, HMV, the list is endless, is anyone even keeping count? It seems like there is little we can do to avoid these closures, but how can they compete when companies like Amazon are able to avoid all taxes? Surely the problem is that we allow these big companies to avoid tax making them a good amount cheaper and yet more profitable than the high street where the costs or business are higher.


Happy Birthday to me!

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Google have a custom doodle for me based on my G+ profile, how cool is that!

Parts of a Vacuum Cleaner

The purpose of this list is to identify major components that I will need to find substitutes, they are not strictly all sub-assemblies, nor are they all individual components.

  • Motor + Fan
  • Wheels
  • Suction hose
  • Tools
  • Filters
  • Handle
  • Cyclone Separator
  • Power cord
  • Power switch
  • Chassis
  • Hose connectors

How hard can it be to buy some bunting – a rant about customer service

buntingI have just finished a phone call with a company I want to deal with, perhaps I am wrong but it really bugs me when you are trying to find a supplier for an item, like oh I don’t know, lets say BUNTING, and you find they sell and all types of bunting to order, some would call them a bunting specialist! Then you discover there are no prices on the website at all, fine let me call them, I mean how expensive can bunting be?


Me: Hello, I am calling to find out the prices of your stock bunting product in red and blue or multi-colour.

Company: How many do you want?

Me: I don’t know, how much do they cost?

Company: You have to tell me how many you want first, there are a lot of price break points.

Me: I don’t know.

Company: Well I can’t tell you the price then.

Seriously WTF!

Me: I dunno, how long are they?

Company: 10 meters each

Me: A hundred then, what ever.

Company: A hundred?

Me: Yes, one hundred buntings.

Shit thats like a kilometre of bunting, who buys a kilometre of bunting?

Company: They will be £4.67 each

Me: Okay and as it’s a sliding scale how much is one bunting?

Company: We don’t sell just one, the minimum is 5.

Does it really have to be this difficult?

Me: Well five then?

Company: £5.42

Me: So they’re almost the same price.

WTF, most people would expect a discount for buying lots so why not say they start at £5.42 each for 5 units!

Company: Yes, plus £12 delivery.

Me: Thanks.


Seriously! Why can’t you answer the question simply stating the price is on a sliding scale, the minimum order is 5 units, which is £5.42 each plus a fixed £12 postage cost. The prices go down to about £5.00 for 50 units, and under £5 for a 100 units or more, and there are various points in between, we can give you a better estimate when you know how many you are looking for.

Business is not difficult if you use common sense, are forth coming with information and make it easy and enjoyable for people to work with you. If you list a load of prices on a website people can take it or leave it, if you don’t people have to really want your product to bother emailing or calling you, what happens if you aren’t there, or the email or phone call don’t make it through.

End of rant.

Image: Ralph Moorhouse

Open Vacuum Workshop #1

This weekend (Sunday 6th January) I held a workshop at The Rag Factory, Bricklane, East London. I invited strangers to attend this workshop as a way to kickstart the process. Though the workshop we started with introductions, it turned out that we had:

  • Barry – Mechanical Engineer/Designer
  • Gangj – Product Design Student
  • Jeffrey – Electrical Engineer
  • Oliver – Interaction Designer

The mix was male orientated, and all had some relationship to the Royal College of Art, although they were not all derived from contacting students. I guess the project appeals a certain type of person?

8360111956_a2d94f33d6_bAnyway next we talked about the idea behind this project, and its founding principal which is that I wanted to examine what happens when the concept of The Maker’s Bill of Rights, Open Source Hardware, The Fixers Manifesto and the general maker/crafter philosophy is applied to the design of every day items, specifically in this case a vacuum cleaner.

Next we watched an episode of Tim Hunkin’s TV series, The Secret Life of Machines, this episode was dedicated to the vacuum cleaner.

After this we started talking about some of the current models of vacuum cleaner, and produced a reasonably extensive plan of those products:


One key issue the group came up with at this point was ‘Who is this vacuum cleaner for?’ The issue is that the vacuum cleaner isn’t designed for mass production, nor to compete on price, and it’s designed by amateurs so it probably isn’t going to be a better vacuum technically than existing models, so what makes it worth building? The answer we came up with was, that this vacuum cleaner might be made by makers for makers because realistically not many people would feel confident enough to make their own, nor would they want to bother with that. So went about plotting what alternative uses we could think of that the vacuum cleaner could serve in addition to the existing role as a cleaning device…


8360112374_dcb02265ed_bNext we started looking at the two vacuum cleaners I had brought along to dismantle and examine, the first was a £29.99 model from Argos (406/7946). Unfortunately the vacuum cleaner was not designed to conform to The Makers Bill of Rights and so although it had standard Phillips head screws they were at the bottom of a very deep and tight hole so we couldn’t get the driver down to them.

To add insult to injury, I had bought a special kit of long security torx drivers as I researched the Dyson we had to take apart and found it used these so as it turn’s out aren’t nessisary on the Dyson as they are all flush with the surface, while the short screw drivers I already had for the Philips and flat head screws didn’t reach quite far enough to open the cheap Argos vacuum cleaner.

We did however take some measurements of the vacuum cleaner at three key points to measure airflow fall off and allow us the make some basic comparisons to the outcome of this project, obviously we did this before trying to take them apart incase it all went tits up.


The three points of measurement were, direct from the motor, this measurement was difficult as the port is larger than the anemometer vane we used to measure it. However the ‘after filter’ was the port on the outside of the machine after filters/bags/cyclones where the hose would normally connect. The hose measurement was the result airflow at the end of the hose and the bendy handle bit.


Interestingly the Dyson doesn’t really loose airflow speed thought this process but the Argos clearly does as the filter impedes the airflow.  Next we unpacked the brand new Dyson DC11 for it’s ‘inspection’…



We performed the same set of tests on the Dyson:


We even used polystyrene balls to visualise the cyclone power, it turns out that even though the Dyson is very powerful and cyclone-y the Nikon D7000 can still capture a still image in mid rotation:


Now we start on the interesting bit, the disassembly, a dark day for this vacuum cleaner, would it ever work again?

The first step was to remove all the ‘accessories’ that come off by design… 8360118492_ecaaa2e63e_b

Strangely the mechanism that Barry is holding there in his left hand actually comes of using a plastic screw, as though it is intended for a user to service but only reveals the life time filter which cannot be removed without full disassembly, we could only presume it aided in cleaning the hose or user replacement of this part as it gets a lot of abuse.


This is where the investment in the T15 Torx driver came into it’s own as every other screw in the machine was a T15 (except one T6 I think). The first part off was the accessory storage bay (above), then the hose clamp/cable guard.8359055487_c9ce2857a2_b

With a half dozen more screws removed we could lift the lid on this beast, and discovered a rather modular and serviceable machine, not unsurprising when Dyson have to service these themselves. The base comprises of three modules, the cable retract mechanism at the front there, you can see the upside down Y shape, that is the break release button. Behind on the right is the lifetime HEPA filter, and to the left is the motor canister, and that is it!


Here you can get a closer look at the base, and see there is a PCB module on the motor canister, which wasn’t surprising as we had already turned the machine on and discovered that it seemed to be a soft start on the motor (where it ramps up power), we also noticed a green LED which seemed to flash for some time whilst it did something before going to green to indicate it was ready, also the power button didn’t operate for short taps but only longer presses.


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To our surprise the motor seemed to be Dyson’s digitally controlled motor, or brushless as the resident EE described it. The motor had phases, each attached to a transistor, through a opto-isolator to another, larger PIC microcontroller which presumably is connected to the power board and it’s radio transmitter chip and antenna.

8359057921_2e22fe98b4_bBarry, the product mechanical engineer got a bit carried away disassembling it and ended up dismantling the entire motor, we learn’t however that the motor has an optical encoder to detect the passing of a cam on the motor shaft, to presumably measure RPM.


Jeffrey the Electrical Engineer got rather excited by the electrical aspects of the product, noting some interesting polyester capacitors and gigantic diodes in a full bridge rectifier converting the 240V mains AC into about 300V DC although he presumed it was not powering the motor at that power through the transistors.


Here is the back of the board, the larger chip in the bottom right is (I think) the PIC.


How does this go back together?


The extracted power switch board, come radio bug thing, strangely it was noticed that in addition to the antenna bit, there was a tri-colour LED which we only ever saw green, but also presumably was able to do Red and Yellow. There was also a buzzer which never buzzed, and both boards had what was presumed to be a reset switch for the PICs, a small ribbon cable connector acted as an interconnect between both boards.


We ended up with a discussion about where we are now, recapped the mission of the project and had a great suggestion about using the exhaust of the motor to blow back into the carpet pile to loosen it before sucking it back up again, this would also allow for a ‘closed loop’ of dust to create recirculate any last particles in the air through the vacuum filters again, and again.


Long post, long day, and lots learned. Some how I am struggling to figure out what the next workshop might entail, however myself and the others agreed it was a great start to the project and my tutor doesn’t currently see what can been gained from another workshop, I wonder if another might be a test build to see how others get on with building the final version, however that would be in February.

I will leave this post with a time lapse of the whole day…

Going underground…


On Saturday I got a very rare chance to visit the abandoned Aldwych London Underground station near Waterloo Bridge, just on the river, there are plenty of reviews and regurgitations of the experience so this is just going to be a picture post.


IMG_2350 IMG_2342 IMG_2304 IMG_2295 IMG_2290 IMG_2276 IMG_2274 IMG_2273 IMG_2265 IMG_2261

Cable Rewind

Another aspect of this project to be examined is the cable rewind mechanism, I have found assemblies online for replacement, but I think I will wait until I take apart the Dyson as I can save buying one this way.


I have been having a look at how I might create suction using motors and initially thought about using a ‘standard’ motor what ever that might be, however I soon realised that the motors inside all vacuum cleaners are specialised for their purpose.

I have found a few companies who make vacuum cleaner motors, with little actual effort:

I specifically looked at YDK vacuum cleaner motors and compiled a list of all the 240V motors and their ‘specifics’:

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I discovered that the vacuum presure is measured in Pascals and that the airflow is measured in Decimetres which is essentially able to convert into litres per second. Interestingly they seem to use dm³/s which seems to be to make the numbers look bigger as dm³/s is just an order of magnitude smaller than m³/s (a decimetre is basically ⅒ of a meter or 10 centimetres).

I was quite shocked at the short life these motors have and at the rotational frequency (RPM)!

With the idea of off the shelf being important, I wonder if using a replacement part from a popular or frequently repaired vacuum might be a better way to go, rather than trying to buy from the manufacturer.