Nixie Tube Clock

For Sale  $250!!!
Here is the last of my Nixie Tube clocks for sale.
This is $70 cheaper than all of the others I have sold, but this is not numbered, dated and/or personalised.
Very accurate, totally cool and mows laws. What more could you want!
Email me if you would like it!   r.batten@optusnet.com.au

This clock is quite safe with the open circuitry, but is not suitable for a position/home where children can get to it.

Breakthrough after breakthrough!

Its been a week of break-throughs, I am pleased to announce.
1. A winner gear tooth profile.
2. Double safety measures for the recently made, yet to be named electric clock.

The first being a new gear tooth profile, has got me grinning from ear to ear. I have spent around 3 years now trying to come up with a tooth profile that works Super efficiently. Basically put, its really easy to make a gear tooth profile that works, and they will work in varying degrees of efficiency of energy transfer from the gear tooth to the mating pinion tooth (smaller of the 2 gears).

 The place where the efficiency is most needed is earlier in the drive chain where there are large amounts of pressure on the teeth. And especially where the next 2 teeth start to engage. What tends to happen with a badly designed tooth profile, is that the newly engaging tooth tends to 'crash' into the face of its mating tooth. This causes a drastic decrease in drive pressure and much more often than not, this is when/where your clock will stop because there is not enough torque to turn the escapement wheel. The trick is to get the 2 new mating teeth to smoothly slide together, like on a tangent. This I have managed to do fairly well in the past with certain gear ratios, but I have found that once the ratio changes the gears don't tend to mesh as well.

This occured to me recently on the Gravity Escapement clock (the one that is a bit like a 4 leaf clover) Gear ratio 64-8 meshed beautifully, but I had to change it to 64-16 to get the drive weight down, and it didn't like it at all. Also some escapements accuracy is dependant on the drive pressure being constant...and a drive pressure that fluctuates up and down as teeth engage is not good. I have 2 of the same clocks sporting different teeth profiles and the different accuracy between the clocks is VERY evident.

So after around 5-6 different gear tooth profile designs and studying many others over a period of around 3 years, I am pretty sure I have cracked it! ...No actually I know that I have cracked it!! Sorry, but I am going to have to keep it a secret on how to reproduce it. :) Whats more, I think that they are quite pretty looking to!


BREAK-THROUGH #2
Not being an electrical engineer by any account, I have been quite worried about running the clock with no supervision. I have once gone upstairs at home for 15 minutes, only to find on my return that the clock had stopped, because the mercury switch got stuck inverted. This has left the coil of the solonoid energised and upon investigation, it was found that the coil had heated up to 67 degrees celcuis! Actually not at all dangerous at that temp, but it can burn skin! The wire will melt at over 300 degrees C and the enamel will burn somewhere between 130 and 300... The coil will most likely reach equilibrium way below that temp (that means energy coming in equals energy going out, or heat from the power to the coil is equal to the heat radiating to the air). BUT I am not keen to try it.

I have tried many types of fuse values and makes, but have not found a solution. Upon talking with a family friend (Tony Roe), who IS an electrical engineer, I found 2 other types of components that I am sure will have it sorted out. Only time will tell, as they are now added into the circuit. The first is a resettable temperature switch. This is mounted on the back of the coil itself, and cuts the circuit if the coil measures a temp in excess of 60 degrees and reconnects the circuit at 45 degrees. The other component I have put into the circuit is a PTC or a "polymeric positive temperature coefficient ". Put simply, its a fuse that when current is drawn through it above its rating, the polymer inside it melts and stops conducting electricity. The current of the coil draws 250 mA for periods of about .7 of a second. The PTC internals melt when a current of over 100mA flows for around 7 seconds...and stay melted untill the current is turned off. Which is actually better than the temp sensor, because the temp sensor will oscillate between on and off as the circuit turns on and off!

So its been agreat week of breakthroughs.
See ya round like a rissole!

Beta of the Electron eata goes like a bought one!

Here she is!  And she's running like a beaut.
Here's a pic of the mercury switch...It now only switches a transistor on and off instead of switching the actual current load that energises the coil. But there is 2 advantages to that. 1 is that I can alter the amount of current that energises the coil with the use of a variable resistor...instead of having to add or subtract windings on the coil, and 2, when the mercury switch was carying the full current load, it was sparking inside and carbon from the 2 electrodes was coming off and blackening the glass. I put a tissue behind it so you can see the switch better...

Here's the transistor with standard resistors...Yeh I know it looks bodgee!

Here's how the mercury switch works...below...
There are 2 systems, the drive system and the time system. What the mercury switch is used for is turning on and off the coil(red thing at the bottom right), which impulses the pendulum and keeps the clock running.

In the first picture below, the pendulum (vertical bit on the right) is swinging from right to left, and the small horozontal arm has caught on of the teeth and is turning it anti clockwise. This action will eventually bring one of the cam lobes around on the black wheel, which will tip the backwards shaped tick arm, which then tips the arm that the mercury switch sits on. It works just like the points in an old cars distributer, because it only impulses the pendulum on and off at a time and duration determined by the shape of the lobe.

Here's how the time keeping system works. Each swing of the pendulum makes the horozontal arc shaped arm (below) catch a tooth on the small count wheel, which slowly tuns the black snail shaped wheel (it takes 1 minute to do one revolution) While the snail shaped wheel is turning it is lifting the black horozontal arm which is resting on it. There is a clear arm hanging from the black horozontal arm and it is lifting a tooth on the large count wheel.

When the snail wheel completes a full revolution, it drops the black arm and the arm clear arm hanging from the black arm drops to pick up the next tooth on the large count wheel.

Below you can see the vertical clear arm enguaged with the large count wheel. The large count wheel has 60 teeth for each minute of the hour. Sorry for the ugly bits of bluetack, but their needed for adding weight. It is a prototype afterall...

Hope you like the pics, I'll put a video up of it soon. It looks great when it's in motion!
cheers
rosco

Beta of the electron eater!

This is (I think) the final design to be made into the production model. Everything in flouro green (including the red and purple count wheels) has been altered because of design shortcomings discovered with the 1st prototype!
The red and purple count wheels went to the dentist to have their teeth reshaped so that the the backstop and pulling arm (respectively) fell into the wheels, not leaving a recess for backlash to occur. (see top right and bottom left yellow bits)

The face no longer supports the centre shafts, as it created too much friction of there was a small amount of twist in the clocks chassis. The new face design looks better too!

There have been 2 lobes added to the cam wheel (above), to make a total of 3 lobes. This will make the impulsing circuit energise the coil every 10 seconds, instead of every 30 seconds. I think that should be enough to keep it running. Only a long run like for an hour or 2 will tell, and I am yet to install the 3 lobe cam into the 1st prototype to see how it goes. Here is what the 1st proto type currently looks like...

I don't like the all black, it was just easier to cut all of the pieces in one cut. When this was first assembled, I wasn't feeling that is was going to all that successful. With the new mods made to the design, I am really confident that its going to run well! Fingers crossed.
cheers
rosco

LATEST UPDATE...
I think I am going to try a Mercury Switch!

Here is a design that could work. The mercury switch is the spaceship looking thing mid left. The long arm on the lever is to amplify the small lobe on the on the cam. We'll see

Count wheel designed

Here is the design of the count wheel version. I think it looks good. Will also be less noisy than the other version with the swinging pawl hitting the pendulum every second. This will impulse every 30 seconds. The trick will be getting the windings on the solonoid right. so that the pendulum doesn't end up swinging a crazy amount. I haven't wound a solonoid before, and I guess that every one is different, depending on the neatness of the windings (sounds weird but true...)
2D pic...

3D pic...

I received my 400 feet of .25mm enamel coated wire yesterday! So I will try to wind the solonoid this weekend. Cooooool

cheers
rosco

HOLD THE PHONES!

After doing a first prototype, it was apparent that it wasn't goin to work real well in the real world. Mainly the fact of too much friction if the clock isn't totally square.

So here is a redesign... There is a chassis out the back that supports both of the main shafts instead of them being supported on the back plane and the front plane. This will work a treat...I think :)
In the picture below, everything on flouro green has been redesigned.

I have kept some of the design cues from prototype1, but have changed the look a bit, so now you can see the electromagnet on the bottom right.
I think it looks much better.
cheers
rosco

Possible count wheel design for electrical impulse

This is a design that could possibly work for making an electrical impulse happen...

When the pendulum (represented with a red line on the right) swings from left to right, it pulls the black arrow looking object with it, which in turn will catch on one of the teeth of the wheel and rotate it clockwise(like the red arrow shows). On the internal black circle, you can see a little hump, which is to the lower left of the red arrow. As the hump turns round with the toothed wheel, you will see that it pushes out the yellow outlined stick, and when pushed all of the way out, the yellow stick (which has an electrode on it), will touch the white stick (which has an electrode on it also), and will create an electrical circuit in turn,impulsing the pendulum. This 15 toothed wheel will basically make the connection happen every 30 seconds, which means that the pendulum will be impulsed every 30 seconds!
We'll see...
cheers
rosco

This one uses electrons!

This has also been in the pipeline for a while...

Inspiration for it comes from Clayton Boyer's "Electra" Which you can see on Youtube.
This design is yet to be finalized, but won't be too far away.
Essentially it is a gearless type clock. A lot of clocks tend to work like this, when there is no weight drive in the chain. But in saying that, you could just use the red toothed wheel to be able to get the movement from the pendulum, and use 2 gear ratios to drive the minute and hour wheel, like a traditional weight driven clock.. The gears would probably introduce more friction though, which would directly impact on the pendulums momentum.

Come to think of it, I think I might change the design and do away with the little catch that swings on the pendulum. Instead I might use a countwheel, to close the electrical contacts. I think it might be less intrusive to the pendulums swing.
I'll keep you up to date!
cheers
rosco

GoodNight,GoodMorning!

Good Night...

Good Morning!

Well, She's still very prototype, but she has run all night for the first time, first go! I think I have said earlier that I love coming downstairs in the morning to see that they have been ticking along by themselves all night while I've been sleeping. We'll see how she keeps going...

P.S. the time wasn't set when I went to bed

P.P.S. Are clocks a he or a she...I think of them as a he, but there is that saying, "Mother Nature, Father Time", so maybe they are he's.

ITS ALIVE!

Here is the Gravity Escapement in real life!
I cut the parts on the weekend...It seems a lot easier to cut than the others...could just be me getting better at creating the tool paths.
It kind of worked when assembled, but if I put too much power into the system with my finger, it would skip 2 or 3 beats.
So I went and redesigned some parts and installed them.

1st leg and wheel prototype...I thought that the small angle faces on the ends of the spokes were slipping off. So i decided to make spokes that required the wheel to be recoiled a little, kind of like a hook, but they just didn't release. Sorry for the bad pics, but you can see it above over to the right with the clear perspex arm.

So I made a new prototype which might release earlier because I thought that the spokes might just be catching on the edge and letting go.

You will see below that the action happens so fast...By looking very closely, I saw that the skipping problem was caused by the small black arm that is close to horizontal was dropping off the steel pegs. So I sticky taped a small piece of perspex above it and that stopped the problem!
Although the escapement was actually working, there was still a problem with it impulsing the pendulum way too much and making it swing too far. You can see above a small bit of aluminium taped to the top of the pendulum and also a small recess ground out of the clear perspex on the bottom right.
Here is a video of the escapement working. But working with a 1 second per swing pendulum instead of what I originally intended to use, which was a 1/2 second swing.

There are a couple of reasons for thinking about going with a 1 second swing over a 1/2 second swing.
1 The escapement is impulsing too much for the 1/2 second swing pendulum, which is caused, I think, by the arm being too heavy being made from the perspex.
2 The large impulse is working great for the 1 second swing pendulum
3 I have already noticed that there is going to have to be a very large weight to drive the clock. That weight can be HALVED INSTANTLY by keeping the 12 spoke wheel and halving one of the gearing ratios.
4 Upon running the clock on the 1 second pendulum, the noise created by the escapement is no where near as a racket only clicking every 2 seconds instead of every second. ( This type of escapement is regarded as one of the most accurate, but it is noisier than most )

Some more pics to have a look at...

Well that's the latest update!
Over the next couple of days, I will be finalizing the escapement design and cut a new gear ratio just behind the escapement from being 40 to 8 teeth, to being 40 to 16 teeth...or i may even change the ratio on the large right wheel from being 60 to 8 teeth, to being 60 to 16 teeth...which is probably a better solution, because it will make the right wheel more similar size to the left side.
Actually no...I'll do the large wheel in the middle, which is 64 to 8 to be 64 to 16, then it will be easier to see the teeth from behind the face. Fewwww. Glad thats over! :)
See ya soon!

Gravity Ratchet re-design

I mentioned earlier that I had redesigned the drive barrel to be 60mm diameter instead of 25mm, so that the larger diameter barrel would have less build-up of string when fully wound. The build up of string creates more drive in the system, and the grasshopper escapement is sensitive to changes those changes. (I'm sensitive to ;)...) Anyway. So because the drive barrel is larger, it now blocks the view of the gravity ratchet which could be clearly seen with the clear perspex versions.

So I've decided to redesign it from being an 'inny' to an 'outy' and I don't mean to be like a belly button. Its basically been turned inside-out or outside-in. now its workings are even easier to see than the original. Nice! Its yet to be prototyped though, but I'm sure it will work great.

cheers
rosco

Final Build for the RB3

Finally here it is the RB3, and another clock that needs to be prototyped...for the 2nd time. There is a picture of the first prototype in the first picture of the post below titles "I think its there!" It is the all black clock on top of the speaker. Looks great! Ill upload a picture at the end of this blog.

But for now here is the redesign.

First of all I have to say that there has been some inspiration taken from a the clock plans that I bought for the making of my first clock which was for Seths 1st birthday. But really, to date the only thing that is even similar are the shape of the plates. There is also another version of this which will sport a childs name, a little mouse on the RHS and the poem "Hickory Dickory Dock" on the stand, which can be made for a childs gift. Which you can see in the earlier post "Seths clock remade with my new skills".

This redesign has a new escapement design with 1 degree of 'drop' and 'lock' instead of two, which should make it quieter, redesigned gear teeth, new drive weight reduction gears which reduce the amount of pulleys to 1 each side and a more modern face that allows the escapement to be easily seen. The CAD pictures above has weirdlt coloured parts, but I plan on making the real version of it in all black, with clear perspex on the numbers and hands only.

Antways...More to come :)

New Design with Gravity Escapement!

Here's my latest design!
Do I really need this now?...no. Can I stop myself?...no. So whats new?...nothing!
This gravity escapement has been in the works on and off now for just over 2 years. I don't have any instructions or dimensions for the design of it, I have just worked it out by watching animations of it on YouTube. There is a 2 impulse version of this escapement, but this is the Arnfield design with 1 impulse per 2 swings of the pendulum. This makes for a more accurate pendulum swing, as the pendulum is left alone for 3/4 of a 2 swing period. There is a little bit of recoil involved in its action, but still this type if escapement is regarded as being quite accurate.

Design of the clock...well it is the way it is, for a number of reasons. I find with a lot of things in life, that if you set a number of requirements, then you find everything else just fits into place. The first requirement was to have it to be able to sit on 1 wall mount instead of 2, as 2 can create issues with level, and also 1 wall mount may be bearing more weight than the other, so it might sag more and create twist in the chassis of the clock and in turn locking it up. The other requirement was that I wanted the gears to be grouped closely together, rather than in a straight line, to make it more compact. So I have used like a 4 leaf clover type arangement.

Then 1 last requirement was to use a Gravity Escapement, which has been the major contributer to the look of the clock. Firstly, I wanted the escapement to be visible, so, because of the way it impulses the pendulum, a simple design solution is to put the pendulum on the front rather than at the back. Also because the pendulum is on the front, the escapement needs to be at the bottom of the clock, so that the pendulum isn't projected way out the front to clear the hands and clock face. Also the use of a circle around the escapement so that it's curious action is nice and visible (see link below). So like I said, some simple requirements, for example the way the clock is mounted, shape and the ability to see the escapement and it kind of designs itself.
A major difference with this design compared to all my others is the pendulum length. It will be using a shorter pendulum with a 1/2 second swing instead of a 1 second swing. To my understanding, a shorter period swing gives a higher "Q" which increases accuracy. The standard Arnfield version of the Gravity Escapement...
http://www.youtube.com/watch?v=U6cUNi-SAOw
 ...has 6 spokes on the wheel (the thing that looks like a sun), but I have doubled the amount of spokes, which means that it will double the amount of time it takes to do one revolution...unless you half the period of the pendulums swing! Well, this is a prototype, so I hope thats the way it will turn out :)
Thanks for reading. Hope you have enjoyed this latest blog entry.
Cheers!

The Metre

The metre
In the discussions leading up to the French adoption of the metric system in 1791, the leading candidate for the definition of the new unit of length, the metre, was the seconds pendulum at 45° North latitude. It was advocated by a group led by French politician Talleyrand and mathematician Antoine Nicolas Caritat de Condorcet. This was one of the three final options considered by the French Academy of Sciences committee. However, on March 19, 1791 the committee instead chose to base the metre on the length of the meridian through Paris. A pendulum definition was rejected because of its variability at different locations, and because it defined length by a unit of time. (However, since 1983 the metre has been officially defined in terms of the length of the second and the speed of light.) A possible additional reason is that the radical French Academy didn't want to base their new system on the second, a traditional and nondecimal unit from the ancien regime.
Although not defined by the pendulum, the final length chosen for the metre, 10⁻⁷ of the pole-to-equator meridian arc, was very close to the length of the seconds pendulum (0.9937 m), within 0.63%. Although no reason for this particular choice was given at the time, it was probably to facilitate the use of the seconds pendulum as a secondary standard, as was proposed in the official document. So the modern world's standard unit of length is certainly closely linked historically with the seconds pendulum.

Copied from Wikipedia. http://en.wikipedia.org/wiki/Pendulum

I think its there!

Sorry its been a while since the last installment, but its not like I have stopped development. Quite the contrary! I wasn't so happy with the last prototype of the RB2 from the point of view that it still had a degree of non-user-friendliness.
The biggest problem I think was the multitude of pulleys. The pulleys are there to allow the clock run for a number of days. For instance, you can have a 1 kg weight driving the clock where it may take the weight 1 day to reach the ground, or you can have a 5 kg weight going through 4 pulleys (which gives a reduction of 5:1) which will allow the clock to run for 5 days. The problem is that the pulleys make rewinding, setup and construction difficult, they also add more and more friction every time another is added. So I worked out that I could use a extra set of gears on the drive train to do the gear reduction for me instead of using pulleys. Heaps easier to make 2 gears, and way less complicated to setup.

I have also developed a clutch type system so that when setting the time on the minute hand, the hour hand moves with it the appropriate amount!

The third big change with this version of the RB2 is the redesign of the Grasshopper. This design changes the pendulum swing from 6 degrees to 3 degrees, which reduces the amount of energy the clock needs to run and also is more accurate. I think it looks nicer too.

The 4th design change is the use of different tooth profiles on the gears and pinions. This version doesn't have the full compliment of new teeth, but other design changes made to the RB3 have shown the new designed teeth to introduce less friction.

The 5th design change was also part of the re-gearing of the drive and getting rid of most of the pulleys. The grasshopper needs a constant drive pressure for accuracy, since it is a recoiling escapement. The problem with the old drive system was that it used a large amount of string around a 30mm barrel. So fully wound the barrel's diameter would build out to around 40mm. So unwound the torque exerted by the barrel was created by a 15mm radius, and fully wound the torque was created with a 20mm radius. That is around a 33% difference in torque! That difference in torque didn't make the clock's accuracy pathetic, but it could be made better. The new geared drive uses 2/5ths of the amount of string and it is wound on a 60mm barrel, so the torque change from wound to unwound is now around 5%. I am very happy with that.

The 6th design change to the clock is yet to be prototyped, but does exist in CAD form. It is an inside out Gravity Ratchet. The original design has been explained in an earlier blog entry. The reason for changing the design is simply for aesthetic reasons. The new barrel which holds the string has been made to have a 60mm diameter instead of a 30mm diameter as per the earlier explanation of the design change #5. Because the barrel is now so large, it blocks the view of being able to see the original enclosed ratchet working, so our with the original and in with the inside out version me thinks!

This version has been a real success. It sprung to life the first time I swung the pendulum and just kept going! It has been running constantly now for at least a month with 1 little hickup in the middle, so I am very pleased with it.
All in all, the clock may look pretty much the same, but it is very different.
Hope you enjoyed the read.

cheers
rosco

RB2 in action

Here is a video of the RB2 in action. This is the prototype for a production model. The production model will have 8mm thick frame plates instead of 4.5mm. Special thanks goes to Steve Thomas for cutting the pics together for me. Hope you like it!

New pictures!

Here are the new pictures for the Perspex version of the RB2. Keep an eye out for the movie of the Grasshopper!