Tilt switch test rig

Rampz

Well-known member
Out of interest, is there enough energy stored in the spring to strike "12" ... so there could be just a single 'wind', rather than many? Would the connection angle of the spring allow it?
I miss understood you Phil, there isn't enough energy in the spring for striking 12, also the spring tension dictates the speed of the chimes, so works best to maintain it the best as possible

not that it was used to stop contact bounce.
It also reveals the snubber you mentioned as being some kind of pulse extender.
Yes i understand the snubber was tring to be a pulse extender to get around the motor seeming to be pulsing as it did, i wasn't involed at that time, i had to try and sort that out, previous to that it was a hall effect switch that drove the motor directly, then for no know reason they changed to a tilt switch and snubber network, but looking back thats where the problems started

The fifteen degrees from the tilt switch means the glob moving from one end of the switch to the other this is not happening to your switch because it is not at the centre of the axis, it is just giggling about on the outer edge
Yes i felt the switch wasn't in the best place therefore wasn't being operated as designed, the tilt switch being used has 2 balls inside, we know because we destroyed on ethe other day, a smaller ball does the contact and a larger ball pushes it, it does mean there isn't much space for the off position, so at that point we tried a mecury version and it seemed to move with a lot less bounce

As a last note , I see from the winding pulse that you are trying to achieve a very quick pulse at regular times so that it makes the clock easier to regulate, though without seconds sweep I think it would not make a damn of difference if you pulsed it every half hour with a two second burst it might be a few seconds faster for the first qua,rter then slower for the last fifteen, easy enough to compensate on the regulation.
I know that from what the winder is doing, it momentarily stops the clock as the winder moves and this is why such a short pulse is presently used.
Each clock has a different requirement, some take 5 mins to reach 15 degrees some take 15 mins to reach the same, giving a pulse for 2 seconds every half an hour for example might have issues on some clocks, they feel its better to have it angle dependant then it will be good for any clock, the other point regards regulation, the clock in the clip had this, but its an add on many clocks get the winder first and may or may not ever get the regulator.

Rampz, is there no "sustaining" or "maintaining" mechanism on a tower clock? Just curious.
Hello rq3 how do you mean? From Phil's post it can be done but it is a seperate unit, costing another few thousands

Yes Rampz, I get that it would be a real problem if the drive kept engaging and driving itself further and further away but it was not moving with a signal that should have made it move, It was being masked
Dave the failsafe plunger was remved during that clip, before christmass it blew the main fuse from being in stall position for some period, so they upgraded it to the timer version from the hall effect version and the vibration seems to be an issue now, what was happening, it was driving 400ms with each pulse and very quickly pulling the safety pin out.

That said, greater logical process can be used even given such a mean trigger arrangement.
Yes i think a PICaxe would be able to deal with that and run normally.

still I can't help thinking one second pulse every half hour is nothing in the grand scheme.
Dave just the issue if this would suit all clcok speeds, with them all being different in their requirements, if you went this route it would still have to be triggered by some type of switch, or you could be all over the place with spring tention
 

David_Reynolds

Well-known member
I miss understood you Phil, there isn't enough energy in the spring for striking 12, also the spring tension dictates the speed of the chimes, so works best to maintain it the best as possible



Yes i understand the snubber was tring to be a pulse extender to get around the motor seeming to be pulsing as it did, i wasn't involed at that time, i had to try and sort that out, previous to that it was a hall effect switch that drove the motor directly, then for no know reason they changed to a tilt switch and snubber network, but looking back thats where the problems started



Yes i felt the switch wasn't in the best place therefore wasn't being operated as designed, the tilt switch being used has 2 balls inside, we know because we destroyed on ethe other day, a smaller ball does the contact and a larger ball pushes it, it does mean there isn't much space for the off position, so at that point we tried a mecury version and it seemed to move with a lot less bounce



Each clock has a different requirement, some take 5 mins to reach 15 degrees some take 15 mins to reach the same, giving a pulse for 2 seconds every half an hour for example might have issues on some clocks, they feel its better to have it angle dependant then it will be good for any clock, the other point regards regulation, the clock in the clip had this, but its an add on many clocks get the winder first and may or may not ever get the regulator.


Hello rq3 how do you mean? From Phil's post it can be done but it is a seperate unit, costing another few thousands



Dave the failsafe plunger was remved during that clip, before christmass it blew the main fuse from being in stall position for some period, so they upgraded it to the timer version from the hall effect version and the vibration seems to be an issue now, what was happening, it was driving 400ms with each pulse and very quickly pulling the safety pin out.



Yes i think a PICaxe would be able to deal with that and run normally.



Dave just the issue if this would suit all clock speeds, with them all being different in their requirements, if you went this route it would still have to be triggered by some type of switch, or you could be all over the place with spring tension
No Rampz , I meant that this is so basic it does not lift a sustaining lever to provide power for a few seconds like the human winder does, therefore the clock power is removed for the time that the spring lever arm takes to move it's travel.
The spring tension will not be a problem if it is slightly over and under since it is reapeatable.

This can be 0.1 second or twenty seconds, it is just a trigger signal that re-tensions the spring , but at this moment in time the clock does not have motive power, but for a second or two it will not matter, but how this would happen if it took twenty seconds to wind up I do not know?

Simply because the mechanical regulator will be adjusted by the clock keeper on a week by week basis, I do not see you at the moment doing it by electromagnetics . unless it is dirt cheap to make and fit.
 

Rampz

Well-known member
I do not see you at the moment doing it by electromagnetics . unless it is dirt cheap to make and fit.
David yep normally its the clock keeper that would go and adjust the clock say once a month etc, he had been doing that for years anyway, the clock time keeping alters with temperature anyway. Its maybe 3k to fit an electronic adjuster, nobody supplies them as matter of course when fitting winders not even Smith's the people in the video clip
 

David_Reynolds

Well-known member
There you go then, design a regulator using Picaxe chip, a real time clock or one of those that gets the rugby signal and keep it down to three hundred quid.
I note their concerns about the spring pressure being all over the place but they can always choose a longer spring with more turns but thicker wire to get the same loading and it would give a longer range of movement within their design limits.
I have been looking at springs, and it grabs me that they are not devices that double the energy per unit of movement, unless they are on their limits, no it seems you get a gradual increase per turn of the coils.
I sense that it has to be pretty close to the torque that the weights would put on in a completely continuous way. but that is not possible using a coil spring,
Instead they choose s spring tension to get them just above and just below, so it averages out to the correct speed every few minutes, hence the 15Deg, and hence their problems, it is a bit of a straight jacket.

Still if it could be electronically controlled then the extra spring tension would be irrelevant, don't know about the chimes speed though, perhaps no one would notice a slight gallop.
 
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Rampz

Well-known member
There you go then, design a regulator using Picaxe chip, a real time clock or one of those that gets the rugby signal and keep it down to three hundred quid.
David yep I have talked about it with them, need an accurate clock or the ability to calibrate it, say seconds per month, or use the rugby signal but there is an issue using that, church roof alarm block the signal so its often back to quartz unless I can find an alternative time base?

They currently manufature the unit as seen in the clip but its plc based, if it could be done by PICaxe then yep lets have a go, a sensor detects what hour it is by counting revolutions from a reed switch, the first revolution being the hour, then compare that to the time and then for the next hour the electromagnet is switched for so many minutes as is needed to bring the time right, this happens for upto 45 mins, then it waits for the clcok to strike and compares the reading again and adjust for the next hour,

The electromagnet attracts or repels so would need to invert feed to it

If the clock is running fast the magnet attracts if its running slow then its the opposite

There needs to be a way to calibrate this function

set time and date

and calibrate the clock

Next project then "clock regulation" will do some thinking
 
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PhilHornby

Senior Member
... or use the rugby signal
psst ... it moved to Cumbria - in 2007 :)
so its often back to quartz unless I can find an alternative time base?
You could always use GPS aka GNSS ... but then you'd have to guard against spoofing ;)
Folk on here tend to swear by the DS3231 ... but if you happen to have a Wifi connection, you can use an ESP8266 and NTP.
sensor detects what hour it is by counting revolutions from a reed switch, the first revolution being the hour, then compare that to the time and then for the next hour the electromagnet is switched for so many minutes as ...
The system I had in mind for my Grandfather Clock, was to count the actual Ticks & Tocks. You seem to have already managed that part, even if by accident!
Next project then "clock regulation" will do some thinking
Count me in.
 

AllyCat

Senior Member
Hi,

Indeed, it's a great little chip. Note that there are (at least) two styles of "breakout" module available. One has a holder (on the rear) for a standard (non-rechargeable) lithium coin cell (e.g. CR2032) and (optionally) may also carry an I2C EEPROM chip. Note that unlike some RTCs, the DS3231 does NOT contain any "spare" (User) NV (battery-backed) RAM. Another style, often called "DS3231 for Pi", is tiny (the soldered 5-pin header socket is the largest part) and carries a soldered-in rechargeable button cell, but beware that some sellers do not supply this (which will be difficult to source later). :(

Cheers, Alan.
 

Rampz

Well-known member
Since we are looking at clock regulation now, which was going to happen at some point anyway, a function of this is time change as daylight saving comes into effect, at this time the clock pendulum is stopped and held by a magnet until 12 hours plus or minus 1 hour to suit and the pendulum let swing again, for this there needs to be a sesnor on the pendulum which happens in clock regulation.

So as a spin off why not use the this sensor to trigger the start of a windup session, maybe the tilt switch is set to be solidly ON at the top position, a button on the picaxe is pressed, the picaxe now counts pendulum swings untill the winding drum has moved say 15 degrees then the user presses the button a second time at which the number is written to eeprom and the motor triggers untill the tilt switch turns it OFF at the first activation?

This way we stop the motor with the tilt switch and maybe a fail safe timer, but then after counting to a number is triggered to rewind, this way it would be nicely setup to suit any clock and always start at the same place?

Is this away to make the tilt switch more reliable?

The next spin off from this is if the motor gets either a low voltage situation or a stall situation, which would means the clock would stop, it could reach out and stop the pendulum making not of the time and when the problem is sorted could then restart the clock at the correct time, a really cool feature!
 

PhilHornby

Senior Member
...at this time the clock pendulum is stopped and held by a magnet until 12 hours plus or minus 1 hour to suit and the pendulum let swing again, for this there needs to be a sensor on the pendulum which happens in clock regulation.
Assuming the electromagnet arrangement, as seen in the previous Youtube video, is it strong enough to actually arrest the pendulum - as opposed to just influencing it❓ (Do you know which specific product it is? - though it may be a bit big for my 🕰)

I was wondering ...
...could such an electromagnet be used as the sensor (when it's not activated!) - so as to generate a pulse for every 'tock'?

Is this away to make the tilt switch more reliable?
I think the tilt switch you're they're using just has its short-comings, in this application. (You could do with one with a transparent casing, so you could see what they are ;) )
 

Rampz

Well-known member
Assuming the electromagnet arrangement, as seen in the previous Youtube video, is it strong enough to actually arrest the pendulum - as opposed to just influencing it❓ (Do you know which specific product it is? - though it may be a bit big for my 🕰)
Phil, they currently use large high power magnets attached to the pendulem, there is an linear actuator that slowly moves out when needed to catch the pendulem, its the magnet on the pendulem that ultimatly grabs the body of the electromagnet rather than through attraction from the elctromagnet itself, i can video a working example so you can see how it works?

I was wondering ...
...could such an electromagnet be used as the sensor (when it's not activated!) - so as to generate a pulse for every 'tock'?
It could possibly be done for your clock, but for the clocks i come across its often the case that the pendulem doesn't swing once per second more like upto once every 2 seconds or anywhere in between

(You could do with one with a transparent casing, so you could see what they are ;) )
The other day we did do that with a glass mercury tilt switch on the test rig, we set the motor really slow and left it counting for 3 days, the tilt number was slightly higher than the turn number but it looked to work better than the ball style tilt switch, i have a pic somewhere of the count after 3 days.
 

Attachments

David_Reynolds

Well-known member
What did you do to stop the extra pulses? Any snubber across the switch? Just enough to keep the signal on for a couple of micros more?
 

Rampz

Well-known member
What did you do to stop the extra pulses? Any snubber across the switch? Just enough to keep the signal on for a couple of micros more?
David, so far we have gone with the closed going open and using a mercury switch, it seems to fall open really well, much better than the canister tilt switch.

We cut a brand new canister tilt switch appart and noticed a black mark 3/4 the way around the inside just where the ball sits in the on position its as if during testing following manufacturing the have used to much current and have marked the inside, strange effect
 

David_Reynolds

Well-known member
Yes, the carbonised surface do to the switch dithering about, I would imagine, relays used for DC control burn a hell of a lot if they are not suppressed in the right manner. It appears bit by bit, over thousands of cycles, and does not need a high current to do it. I think the only really continuously successful way is a sealed optical switch operated well within its limit. But that may be for another time.

PS. I do not know why you should have a brand new one blackened though?
 
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David_Reynolds

Well-known member
psst ... it moved to Cumbria - in 2007 :)

You could always use GPS aka GNSS ... but then you'd have to guard against spoofing ;)
Folk on here tend to swear by the DS3231 ... but if you happen to have a Wifi connection, you can use an ESP8266 and NTP.

The system I had in mind for my Grandfather Clock, was to count the actual Ticks & Tocks. You seem to have already managed that part, even if by accident!


Count me in.
Thanks for the update on that Phil,,, It will have been stolen by them, so I will call it by, the "Rugby Signal stolen by the Cumbrians" eh, eh, maybe sooner or later they will be shamed into giving it back!

There is always someone waiting to take away what you have got.
 

PhilHornby

Senior Member
Thanks for the update
I worked for a firm who had deployed "Rugby Clock Receivers" to dozens of sites, to paper over (some of) the deficiencies in their software (Windows 98 constantly lost time). They couldn't understand why it hadn't fixed the problem - until I discovered they were actually using the signal from Frankfurt instead :).

(I fixed the problem by borrowing the philosophy used by Windows NT - sync the OS clock with the real-time clock, at regular intervals. Windows 98 and earlier only did it at boot time).
 

David_Reynolds

Well-known member
I worked for a firm who had deployed "Rugby Clock Receivers"

You have got to watch what you are buying, I did not know. and bought the same thing once.

Now I want nothing from a region that gives us so much disdain.

Sorry I am now running off topic.
 
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