CRX Rotary - 6th Annual BLF/ Old Lumens Contest Winner

I like how you simulated wood grain in the copper surface. :person_facepalming:

CRX is over-the-top with his sanding and polishing. I’m not that patient. :weary:

I’m sure this will be amazing as per usual for CRX. :slight_smile:
Where do you get your copper from?

It’s really only a quick three stages I do for shining the metal after filing - sandpaper, wire wool
then liquid polish on newspaper.
I’m not too fond of polishing, I’m more of a filing hacking & sawing kinda guy yi know :smiley:

The larger copper tube is standard 22mm plumbers pipe, the smaller stuff was sent to me by kiriba-ru a while ago. Same stuff I made this with.

I was just wondering if your metal supplier new what you did. :slight_smile:

Well the plumbers don’t as they probably wonder where their scrap pieces disappear to… unless they have a suspicion the spark on the job has a copper cutting fettish or something :smiley:

Making the mechanical rotary tail switch.

Copper washer.

Using a scrap piece of 0.3mm copper sheet I drilled a 4mm hole and filed the outer edge into rough shape with the file before switching to the finer stone then a quick polish.

Sprung brass switch contacts & enclosure supports.

I used an old brass Zippo flint stopper to make a switch contact.

Filed the brass rod down a little, sanded and soldered to a silver coated spring from an old clicky switch.

Cut two contact enclosures from 3mm x 0.5mm brass tube and filed down to 5mm length then neatened up with the fine stone & sandpaper.

Two sprung pieces, only one is for making the circuit, the other is made to balance the switch disc, is non conductive and also showing a 5mm x 4mm brass tube to be filed down to 3.8mm length for the central pillar support.

Some switch pieces.

Rotary switch contact boards.

Using the FR4 copper board again, I drilled, cut & filed an 18.92mm diameter disc with a 4mm centre hole.

Using the first as a template I sanded down the second using an M4 brass bolt & nut holding them together.

Now we have two equal contact discs

I marked six points on one as well as I could freehand.

Further marked, kapton tape applied to both sides then I cut out the tape roughly where marked with a scalpel blade.

I used ferric chloride to dissolve away the copper that was not covered with the tape, this takes a few minutes.

Pieces removed from the acid bath, cleaned and tape removed from boards to leave copper contact points hopefully where I want them.

A little more tidying up and ready for test assembly. It is not OSH Park quality but it is all hand made Order of how the parts go together. The brass contact enclosures will be soldered in place to the disc later.The steel washer is temporary to hold the contacts in place and will not be used when everything is soldered.

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Amazing… :open_mouth:

Not clear to me what the purposes of the parts are though, but it’s clear you have a well thought out plan. :+1:

Thanks mate :beer:
There are still some components to go into it, but I ran out of solder paste, hopefully that will arrive within the next few days.

That is a work of art in miniaturisation. I have no idea how you do work like that. :+1:

Incredible stuff! Makes me wonder why I bother. :wink:

^ Exactly…

To impress us mere mortals with amazing wood working skills. :heart_eyes:

awesome as usual.
I missed the BooBoo pic :smiley:

Cant believe its contest time already, Another year passed too fast

That switch work alone is just crazy… :open_mouth:

By now, you surely have copper, brass, & lead poisoning at the least…. :stuck_out_tongue:

Quite possible, might explain a few things.. :D

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Redesigned rotary switch contact board.

So, after thinking about the contact board further I realized it had a design flaw so I made a new board :FACEPALM:
The contact points should have minimal space between them to minimize LED flashing effect when changing modes.
Start again, I cut out & drilled a board from the FR4 same as before.

The red circle shows where the sprung brass contact corresponds.

This time I decided to make a small wedged shaped copper piece to help me mark out the contact points on the board, the little hook catches in the centre hole.

Works like this.

Holding the copper marker in place I score the kapton tape with a scalpel blade, move it to the next section leaving a thin gap and repeat then take out the unwanted trace lines and place the board in the ferric chloride solution again.

After a few minutes the board is removed from the solution, cleaned and the remaining kapton removed.

This is a far superior design to the original, I think ;)

Soldered the contact enclosure posts in place and filed down, sanded & polished the brass centre bolt.

Soldered the brass bolt in place using the M4 nut tightened on the other side to keep it straight then soldered on a 10mm x 8mm x 2mm neodymium ring magnet which fits around the head of the bolt, this will be the negative cell contact.

Anti-surge 1% tolerance resistors soldered onto contact board and holes drilled for vias.

The resistor values are: 1R, 3R3, 15R, 180R, 820R to give five main modes, there will also be another direct drive connection which will double as the neutral charging unit connection.

First test of the rotary switch :-) :THUMBS-UP:

The switch can start from the highest mode or lowest depending on which way it is turned.

Way cool!!! :+1: :slight_smile: :smiley: :beer:

I love this rotary switch! I guess the contact rods are round enough to not connect 2 pads at the same time?

It’s just one contact rod, the other is only there to balance, has a piece of plastic on the end of the spring.
I did round the end of the brass post slightly but don’t think it matters as the least resistive path will be taken, I’m sure both pads are connected momentarily during rotation, this was partly the reason for remaking the board with larger pads/ minimal gaps, the transition is a lot smoother although doesn’t show that well in the gif.
Still some tweaking to be done on it too but it’s working pretty well as intended.

You are right, with the given steps from resistor to resistor you probably won’t even see when 2 of them are connected at the same time.