Narrow-Bandwidth Television Association

Can anyone else see them?

gary wrote:Can anyone else see them?

Hi Gary i tried again today you should see them now .

I am not sure what happened yesterday but looks like it has worked today .

Well as you see ( IHOPE) I have reused a computer power supply to run every thing ,thats bolted to the case .

The circuit board connectors i use to hold the circuit board up right so easy to remove and replace work on and such .

Not sure i will need all 4 slots i can make the circuits tigher now i know what worked last time ,and again don't have to make a power supply .

I have more space for the luxeons this time they will fit next to where the middle stepper motor is .

One thing Gary that i was thinking of while i was testing the stepper motors you know when you wire them wrong and they just vibrate back and forth......this has got me really interested for one they are doing this with some Torque and i should think to the frequency of the clock you are trying to get it to turn with ..is this like a cheap way to do a Laser Galvanometer...something i will look into to

Yes it works now Harry - thanks - it is all looking good I must say.

I've always found it annoying that CD/DVD drums have a taper, or conical shape, they would be so much more useful if they were cylindrical - I wonder why they do that? Stacking perhaps? Or maybe it is easier to manufacture them that way.

Yes Harry, I believe it is possible to use a stepper as a galvanometer. I ran to my newsletter CD because I thought I remembered the NBTV laser "guru" Colin Hopper using them as such (V27.4), alas he also has only heard of them being used as such. Note that an ordinary DC motor may also be used that way - as used in many a cheap laser light show kit.

I should also mention, for what it is worth, that if you could find a stepper motor with a step angle of 22.5 degrees you could run it at 750 RPM from a mains derived (through a transformer) signal with just a single capacitor. If you could find a 45 degree stepper you could run it at 1500 RPM.

I have never seen such a stepper, but Harry, you are such a good "scrounger" maybe you will find one. If you do, save one for me!

gary wrote:Yes it works now Harry - thanks - it is all looking good I must say.

I've always found it annoying that CD/DVD drums have a taper, or conical shape, they would be so much more useful if they were cylindrical - I wonder why they do that? Stacking perhaps? Or maybe it is easier to manufacture them that way.

Yes Harry, I believe it is possible to use a stepper as a galvanometer. I ran to my newsletter CD because I thought I remembered the NBTV laser "guru" Colin Hopper using them as such (V27.4), alas he also has only heard of them being used as such. Note that an ordinary DC motor may also be used that way - as used in many a cheap laser light show kit.

I should also mention, for what it is worth, that if you could find a stepper motor with a step angle of 22.5 degrees you could run it at 750 RPM from a mains derived (through a transformer) signal with just a single capacitor. If you could find a 45 degree stepper you could run it at 1500 RPM.

I have never seen such a stepper, but Harry, you are such a good "scrounger" maybe you will find one. If you do, save one for me!

Yes gary happy with it so far ,have to do some wiring up and do the second stepper motor driver circuit .

I am not sure how bad the conical shape is on the drum as its a lot better than my last tub each line had to be hand adjusted or i would have had v shaped slit lines but i made it work so there are ways around it ...it must be very slight on the dvd drum as its given me no problems .

Thats good to know on the stepper galvanometer thing ,i like it because they start and stop same place i think a normal dc would be a be sloppy doing it you would need springs and stoppers each side of the turn...it will look into that newsletter you must have these gadgets listed



Thanks for the info also on the 22.5 stepper sounds like that one would be easy to double the speed with a pulley system .
Is the voltage critical on mains run bipolar stepper,i know it works of the mains frequency i am not sure but are we talking a very low voltage secondary 5v or below ? i tried 6v and just got buzzing .

Oh yes sure will if i track some thing good down ,trouble with steppers tend to be in something big that we want anyway ...

Harry,

Where do you purchase the 'Meccano' perforated strip?

Looks like it makes mechanical construction quick and neat,

Graham

Not to steal Harry's thunder here, but that is a common item in the hardware/building supply stores here in Australia. I have seen it in Bunnings and that is my guess as to where Harry purchased it - let's see if I am right .

Thanks Gary,

Graham

AncientBrit wrote:Harry,

Where do you purchase the 'Meccano' perforated strip?

Looks like it makes mechanical construction quick and neat,

Graham

Hi Graham Bunnings warehouse Gary spot on there ,i don't think they are in the UK..you would have something like that store in the UK ? sells tools do it your self stuff...Yes those metal strips are sort of meccano like ...i like them use them al the time for mounting stuff just need nuts and screws bolts.

I try to do neat a big reason i like the mechanical part of NBTV is i am not really good at that part of it but i enjoy the challenge i suppose you get better at it more you try .

Well you can be proud of the look of this one Harry, it's looking great.

On the subject of hardware stores, have you been to one of the Masters stores? (not up here yet). I am hoping that they will have a greater range of things we are interested in since they are part owned by the US Lowes organisation. In particular I would like it confirmed they are stocking Poplar timber and other varieties other than Pinus Crapiata (you know that stuff Bunnings sells that is full of knots, holes, and is bent like a boomerang).

gary wrote:Or maybe it is easier to manufacture them that way.

It's more that it's impossible to make them another way.

To have straight sides on a large moulded part the mould must be at least two parts so you would get a seam line.
In a single part mould there has to be a slight "draft angle" of two or three degrees otherwise the part can't be ejected from the mould.

Interesting - I could conceive of it being more difficult but would not have even imagined it being impossible. Now I'll be looking for the seam on every cylindrical plastic object I see .

gary wrote:Well you can be proud of the look of this one Harry, it's looking great.

On the subject of hardware stores, have you been to one of the Masters stores? (not up here yet). I am hoping that they will have a greater range of things we are interested in since they are part owned by the US Lowes organisation. In particular I would like it confirmed they are stocking Poplar timber and other varieties other than Pinus Crapiata (you know that stuff Bunnings sells that is full of knots, holes, and is bent like a boomerang).

Thanks Gary I sort of taken the approach you need to house the thing and due to my lack of wood working skills or making cases in general taken a the simple approach ......well for me anyway .

I worked on the computer power supply today,i have all the voltages connected there really just need the 5 volt at the moment and gray wire to switch the supply on from the case ..but never know so why waste them ...BTW it tends to be the green on older power supplies for those that don't know( green to ground or in my case it gray .

Masters i don't think we have those in Melbourne mmmmm i will have to google .

Yes Bunnings is cheapo on a lot of stuff the wood costs a bit but i stick to pine....again due to my poor skills along those lines if i get better at it i will buy better stuff...got my self a router the other day wishful thinking i will improve my skills , do you go to the bunnings in warrawong?

I will work some more on the project now get that second stepper motor going.

harry dalek wrote:Masters i don't think we have those in Melbourne mmmmm i will have to google .

My understanding is that is where they have opened first:

http://www.insideretailing.com.au/IR/IR ... -2213.aspx

harry dalek wrote:do you go to the bunnings in warrawong?

No, Mittagong is closer.

I have Home Hardware and Magnet Mart available to me as well.

gary wrote:

harry dalek wrote:Masters i don't think we have those in Melbourne mmmmm i will have to google .

My understanding is that is where they have opened first:

http://www.insideretailing.com.au/IR/IR ... -2213.aspx

harry dalek wrote:do you go to the bunnings in warrawong?

No, Mittagong is closer.

I have Home Hardware and Magnet Mart available to me as well.

Hi Gary i had a look most are 40km from me but ones around an area i work its a bit tucked away in a side street really have to know to find it,i never really heard of them till you told me about them ,all i knew around here was Bunnings and mitre 10...Spot light is good for other stuff like plastic or glass mirrors art supplies////i don't suppose theres any in Roberston still.

Next time i have some free time i will check them out .

Well, it's just that I have hopes for Masters introducing some real competition, unlikely I know. I am mostly interested in the fact that it appears they will be stocking Poplar timber, and possibly some other timber varieties. Whilst Bunnings is a huge store they only seem to have a lot of the same thing, i.e. they don't have much variety, or an extensive catalogue. Also, lot of people don't realise we are paying 2-5 times the amount for tools, and especially timber, than, say the US do.

I find it amazing, considering the strength of our dollar, that we seem to be paying higher prices than ever for hardware.

Anyway, forgive my rant, I have gone way off topic so I leave it there.