Need a keel wind up counter.

FullCircle

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My lifting keel is on a screw thread which stays positionally stationary when winding up and down.
It takes 105 turns on the head (fitted with winch handle octagonal socket) to go up and the same 105 in reverse to get it down.
The head is about 30mm in diameter, and the wooden/GRP keel box in in proximity.

I would like to fit a counter, either mechanical or electronic which will count up and down depending on keel winding direction.

I was thinking about a hall effect switch and magnet, but am a bit clueless on microcontroller. I have seen the heads on ebay for about 12 quid, I dont think thats a problem.
Any process engineers out there able to help with a list from say Farnell or RS (or even Maplins but I could not find anything there) components I can build a system from?

I will worry about marinising it.

Thanks
 

ProDave

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You will need two sensors, out of phase, so the counter knows the direction (by which sensor turns on first)

What you will be creating is an incremental rotary encoder, described here http://en.wikipedia.org/wiki/Rotary_encoder

That's the theory of how it works. What hardware are you planning on using, is there a particular microcontroller you had in mind?

Now you know how to do it, are you really sure an electronic counter and a microcontroller is really what you want?

Is there no mechanical device you can use?

My own lifting keel has a screw you turn with a winch handle, a bit like yours, but the "nut" that slides along the screw is clearly visible, so it's obvious when it's up, down, or part way.
 

FullCircle

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You will need two sensors, out of phase, so the counter knows the direction (by which sensor turns on first)

What you will be creating is an incremental rotary encoder, described here http://en.wikipedia.org/wiki/Rotary_encoder

That's the theory of how it works. What hardware are you planning on using, is there a particular microcontroller you had in mind?

Now you know how to do it, are you really sure an electronic counter and a microcontroller is really what you want?

Is there no mechanical device you can use?

My own lifting keel has a screw you turn with a winch handle, a bit like yours, but the "nut" that slides along the screw is clearly visible, so it's obvious when it's up, down, or part way.

Dave, thanks. Lifting keel screw not visible, nut does not move.

No planned hardware, needs recommendations thanks.
 

FullCircle

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You could use a bale counter from a farm elevator. A simple device which is tripped by a lever when ever a bale passes.They count up to 999 then reset to zero, I think it works in both directions. I have one somewhere I will dig it out and post you a piccy if its any good.

Thanks, that would be useful. Agricultural sounds good.....
 

ccscott49

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We used to uise a thing called a "ubermeter", to count up and dopwn on wireline in the oilfield, simply a mechasnical counter, would be ideal for you as its mechanical, they actual counter name defeats me, but they are available. Simple bit of kit, just rotating numbers, linked together.
 

FullCircle

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We used to uise a thing called a "ubermeter", to count up and dopwn on wireline in the oilfield, simply a mechasnical counter, would be ideal for you as its mechanical, they actual counter name defeats me, but they are available. Simple bit of kit, just rotating numbers, linked together.

Quick Google has revealed...not a lot. Got a better clue Col?
 

Poignard

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Small pulley attached to shaft.

Length of light line attached to pulley with small weight at the other end (like a well bucket)

Weight at the top= centre board up

Weight at bottom = centreboard down

Calibrated scale, if required, behind weight
 

FullCircle

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Small pulley attached to shaft.

Length of light line attached to pulley with small weight at the other end (like a well bucket)

Weight at the top= centre board up

Weight at bottom = centreboard down

Calibrated scale, if required, behind weight

Sadly, only available sight is the winch handle socket at the top, and the top odf the GRP box, which is surrounded by teak table and box leg.
 

nimbusgb

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A long way from my boat! :(
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FullCircle

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Looks good.

Who would advise on the sensor to mount on the keel screw to supply the signal?

I still reckon that electronic is OTT :) but, if you are determined I can let you have a HE sensor. It's pretty small, like a transistor with three wires. One goes to power supply, one to earth and the other to the counter. Effectively you would wire it across the counter switch shown in the circuit diagram which is shown as a link from the link I posted earlier.
I would try it like that as a first attempt. The circuit may need a bit of playing around afterwards, but it will probably be Ok with nothing else needed at all.

Magnet mounted on the keel screw or even on the winch handle.

You need to rig it up so that the sensor gets to within about 4-5mm of the magnet.

OTT, but what the hell! :)
 

Wunja

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You need Lego!
5206-0000-XX-12-1.jpg
 

srp

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0-99 counter. The input (shown as the little square wave in the middle) would be replaced with, say, a microswitch on the shaft, which is fed into a bcd decade counter. The displays are 7 segment led's, run from a bcd to 7 segment decoder. The various square buttons are latching logic switches which give a hi or lo input so you can reset or stop the counting. The chip at the LH end is an AND gate which acts as the input to the 'tens' display (tens as in hundreds, tens and units if you see what I mean). A bit garbled I'm afraid - I made a few of these some time ago but I'm a bit rusty - all the components came from Rapid Electronics.
You could add a third display if you really needed to count up to 105, just add another set of components.

It's taken me so long to type this you've had another 4 or 5 replies from others in the meantime!

A decent size image - the attached one got crunched by the forum software
5570863540_f443bc57c8_b.jpg
 
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FullCircle

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0-99 counter. The input (shown as the little square wave in the middle) would be replaced with, say, a microswitch on the shaft, which is fed into a bcd decade counter. The displays are 7 segment led's, run from a bcd to 7 segment decoder. The various square buttons are latching logic switches which give a hi or lo input so you can reset or stop the counting. The chip at the LH end is an AND gate which acts as the input to the 'tens' display (tens as in hundreds, tens and units if you see what I mean). A bit garbled I'm afraid - I made a few of these some time ago but I'm a bit rusty - all the components came from Rapid Electronics.
You could add a third display if you really needed to count up to 105, just add another set of components.

It's taken me so long to type this you've had another 4 or 5 replies from others in the meantime!

A decent size image - the attached one got crunched by the forum software
5570863540_f443bc57c8_b.jpg

looks good. Does it work in reverse from 105 back to 0?
 

Phoenix of Hamble

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The problem with any microswitch (or for that matter magnetic pulse or HE) based system is that you need two switches to determine the direction of rotation, and then you have to make logic decisions on the direction of rotation, deciding on time between pulses etc, as well as allowing for error conditions such as stopping winding between switches.....

IMHO, a mechanical system would be more sensible in this case, especially given the need to marinise and power any electronic system.
 
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