Slowing solenoid action?

[Rick C]

On Sunday, October 27, 2019 at 5:02:49 AM UTC-4, Jan Panteltje wrote:

On a sunny day (Sun, 27 Oct 2019 08:15:02 +0000) it happened Jeff Layman
jmlayman@invalid.invalid> wrote in <qp3jm6$bra$1@dont-email.me>:

On 26/10/19 15:19, Terry Pinnell wrote:
Is it possible, perhaps using PWM, to slow down the action of a solenoid while still
maintaining most of its force?

By way of background, I'm considering a solenoid for pressing a rather firm button.
The only one I have at present that can do so reliably is a 24V type that delivers
its press too fast and too noisily. Lower voltage types (already owned or researched
on ebay or Amazon) seem too weak.

I'm recently into Arduino and am also considering the alternative of coding a sketch
to do it with a small servo. The downside would be the extra mechanics.

Any other suggestions of applying a firm linear push over 2mm? Reversing it
consistently, ready for the next application, is obviously required. Although an
intermediate short spring might allow some tolerance.

Terry, East Grinstead, UK

No solenoid.

Motor, gearbox, eccentric cam. Use motor speed and/or gearing to set
operation parameters.

Piece of rubber between solenoid and button?

Better a felt pad to protect the button, and another to cushion the solenoid shaft stop to prevent the thunk.

https://www.ebay.com/sch/i.html?&_nkw=felt+pads+scotch

--

Rick C.

+ Get 1,000 miles of free Supercharging
+ Tesla referral code - https://ts.la/richard11209

 

[Jan Panteltje]

On a sunny day (Sun, 27 Oct 2019 20:49:23 -0700 (PDT)) it happened Rick C
<gnuarm.deletethisbit@gmail.com> wrote in
<3f8df0e8-6be8-41ea-b36f-383d2bb30339@googlegroups.com>:

On Sunday, October 27, 2019 at 5:02:49 AM UTC-4, Jan Panteltje wrote:
Piece of rubber between solenoid and button?

Better a felt pad to protect the button, and another to cushion the solenoid shaft stop to prevent the thunk.

https://www.ebay.com/sch/i.html?&_nkw=felt+pads+scotch

Yes, good idea
Bought some new furniture at Ikea and have been adding those felt pads just last week to the chair legs.
Also bought this chair there:
https://www.ikea.com/nl/nl/p/kullaberg-bureaustoel-grenen-zwart-10320341/?bvrrp=Main_Site-nl_NL/reviews/product/2/ART-10320341.htm
it does not need those pads, and is what I use now for working on a bench with electronics.
swing around

 

[Michael Terrell]

On Saturday, October 26, 2019 at 10:19:09 AM UTC-4, Terry Pinnell wrote:

Is it possible, perhaps using PWM, to slow down the action of a solenoid while still
maintaining most of its force?

By way of background, I'm considering a solenoid for pressing a rather firm button.
The only one I have at present that can do so reliably is a 24V type that delivers
its press too fast and too noisily. Lower voltage types (already owned or researched
on ebay or Amazon) seem too weak.

I'm recently into Arduino and am also considering the alternative of coding a
sketch to do it with a small servo. The downside would be the extra mechanics.

Any other suggestions of applying a firm linear push over 2mm? Reversing it
consistently, ready for the next application, is obviously required. Although
an intermediate short spring might allow some tolerance.

Adjustable air dashpots were common in Broadcast tape machines to control force and to set the timing. A needle type valve allowed you to set it to the desired action. They were quite reliable. I never saw a bad one.

 

[Clive Arthur]

On 26/10/2019 15:19, Terry Pinnell wrote:

Is it possible, perhaps using PWM, to slow down the action of a solenoid while still
maintaining most of its force?

By way of background, I'm considering a solenoid for pressing a rather firm button.
The only one I have at present that can do so reliably is a 24V type that delivers
its press too fast and too noisily. Lower voltage types (already owned or researched
on ebay or Amazon) seem too weak.

I'm recently into Arduino and am also considering the alternative of coding a sketch
to do it with a small servo. The downside would be the extra mechanics.

Any other suggestions of applying a firm linear push over 2mm? Reversing it
consistently, ready for the next application, is obviously required. Although an
intermediate short spring might allow some tolerance.

Terry, East Grinstead, UK

I doubt you'll find a 24V device, and it would probably be too slow, but
a wax motor may work. They're often used in dishwashers instead of a
solenoid.

Cheers
--
Clive

 

On Monday, 28 October 2019 14:09:11 UTC, Michael Terrell wrote:

On Saturday, October 26, 2019 at 10:19:09 AM UTC-4, Terry Pinnell wrote:
Is it possible, perhaps using PWM, to slow down the action of a solenoid while still
maintaining most of its force?

snip

> Adjustable air dashpots were common in Broadcast tape machines to control force and to set the timing. A needle type valve allowed you to set it to the desired action. They were quite reliable. I never saw a bad one.

a simple fanblade type might suffice here. Or if it's a one off, a dashpot from a cassette player door.


NT

 

[Winfield Hill]

Clive Arthur wrote...

... a wax motor may work. They're often used in
dishwashers instead of a solenoid.

Wow, what a concept. $12 as a replacement part,
and with nice mechanical mounting features. But,
oops, do they run on low-voltage DC, or 120Vac?


--
Thanks,
- Win

 

[Clive Arthur]

On 28/10/2019 14:54, Winfield Hill wrote:

Clive Arthur wrote...

... a wax motor may work. They're often used in
dishwashers instead of a solenoid.

Wow, what a concept. $12 as a replacement part,
and with nice mechanical mounting features. But,
oops, do they run on low-voltage DC, or 120Vac?

AIUI, generally 120/240V using a PTC thermistor as a self-regulating
heater, but it seems you can quite easily disassemble and replace the
thermistor with a lower resistance type.

Cheers
--
Clive

 

[Terry Pinnell]

Terry Pinnell <me@somewhere.invalid> wrote:

Is it possible, perhaps using PWM, to slow down the action of a solenoid while still
maintaining most of its force?

By way of background, I'm considering a solenoid for pressing a rather firm button.
The only one I have at present that can do so reliably is a 24V type that delivers
its press too fast and too noisily. Lower voltage types (already owned or researched
on ebay or Amazon) seem too weak.

I'm recently into Arduino and am also considering the alternative of coding a sketch
to do it with a small servo. The downside would be the extra mechanics.

Any other suggestions of applying a firm linear push over 2mm? Reversing it
consistently, ready for the next application, is obviously required. Although an
intermediate short spring might allow some tolerance.

Terry, East Grinstead, UK

Thanks all, rich seam of ideas to consider there!

BTW, no access to bypass the button, or I'd have gone that route. It's on a Polaroid
CUBE:
https://www.dropbox.com/s/q091oh3fpan8hwp/CUBE-2.jpg?raw=1

I'm going to revisit the solenoid, with damping initially and then maybe play with
PWM. But favourite is the servo, as the Arduino code is working for the first stage
of the project, pressing the button for 3 s to power up the CUBE. I'm looking
forward to getting off the PC and playing with linkage methods.

Size and weight are obvious factors. My servo's height to top of rotor is about 3
cm. Solenoid is four time larger and probably ten times heavier. CUBE is about 45 gm
and sides are 3 cm.

Prize for the most novel has to be the wax motor. But at 120/240V and with an
operating time measured in secs not ms, I think not.
https://www.youtube.com/watch?v=sApyrDEXGAI (try t ~ 4 mins).

 

[Lasse Langwadt Christense]

lørdag den 26. oktober 2019 kl. 16.19.09 UTC+2 skrev Terry Pinnell:

Is it possible, perhaps using PWM, to slow down the action of a solenoid while still
maintaining most of its force?

By way of background, I'm considering a solenoid for pressing a rather firm button.
The only one I have at present that can do so reliably is a 24V type that delivers
its press too fast and too noisily. Lower voltage types (already owned or researched
on ebay or Amazon) seem too weak.

I'm recently into Arduino and am also considering the alternative of coding a sketch
to do it with a small servo. The downside would be the extra mechanics.

Any other suggestions of applying a firm linear push over 2mm? Reversing it
consistently, ready for the next application, is obviously required. Although an
intermediate short spring might allow some tolerance.

Terry, East Grinstead, UK

is the plunger not pressed against the button when it is off? iow is it hitting the button instead of pressing the button?

 

[Terry Pinnell]

Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:

lřrdag den 26. oktober 2019 kl. 16.19.09 UTC+2 skrev Terry Pinnell:
Is it possible, perhaps using PWM, to slow down the action of a solenoid while still
maintaining most of its force?

By way of background, I'm considering a solenoid for pressing a rather firm button.
The only one I have at present that can do so reliably is a 24V type that delivers
its press too fast and too noisily. Lower voltage types (already owned or researched
on ebay or Amazon) seem too weak.

I'm recently into Arduino and am also considering the alternative of coding a sketch
to do it with a small servo. The downside would be the extra mechanics.

Any other suggestions of applying a firm linear push over 2mm? Reversing it
consistently, ready for the next application, is obviously required. Although an
intermediate short spring might allow some tolerance.

Terry, East Grinstead, UK

is the plunger not pressed against the button when it is off? iow is it hitting the button instead of pressing the button?

During testing with the solenoid a few days ago I had a rubber grommet between the
plunger and the hard plastic button of the CUBE (shown in my screenshot yesterday).
But the thunk was still unacceptably aggressive and noisy.

 

[Rick C]

On Tuesday, October 29, 2019 at 5:44:24 AM UTC-4, Terry Pinnell wrote:

Lasse Langwadt Christensen <langwadt@fonz.dk> wrote:

lørdag den 26. oktober 2019 kl. 16.19.09 UTC+2 skrev Terry Pinnell:
Is it possible, perhaps using PWM, to slow down the action of a solenoid while still
maintaining most of its force?

By way of background, I'm considering a solenoid for pressing a rather firm button.
The only one I have at present that can do so reliably is a 24V type that delivers
its press too fast and too noisily. Lower voltage types (already owned or researched
on ebay or Amazon) seem too weak.

I'm recently into Arduino and am also considering the alternative of coding a sketch
to do it with a small servo. The downside would be the extra mechanics..

Any other suggestions of applying a firm linear push over 2mm? Reversing it
consistently, ready for the next application, is obviously required. Although an
intermediate short spring might allow some tolerance.

Terry, East Grinstead, UK

is the plunger not pressed against the button when it is off? iow is it hitting the button instead of pressing the button?

During testing with the solenoid a few days ago I had a rubber grommet between the
plunger and the hard plastic button of the CUBE (shown in my screenshot yesterday).
But the thunk was still unacceptably aggressive and noisy.

That's because you want something less springy and more absorbant like felt..

I'm just sayin'...

--

Rick C.

-+ Get 1,000 miles of free Supercharging
-+ Tesla referral code - https://ts.la/richard11209

 

[Rick C]

On Monday, October 28, 2019 at 1:27:37 PM UTC-4, Terry Pinnell wrote:

Terry Pinnell <me@somewhere.invalid> wrote:

Is it possible, perhaps using PWM, to slow down the action of a solenoid while still
maintaining most of its force?

By way of background, I'm considering a solenoid for pressing a rather firm button.
The only one I have at present that can do so reliably is a 24V type that delivers
its press too fast and too noisily. Lower voltage types (already owned or researched
on ebay or Amazon) seem too weak.

I'm recently into Arduino and am also considering the alternative of coding a sketch
to do it with a small servo. The downside would be the extra mechanics.

Any other suggestions of applying a firm linear push over 2mm? Reversing it
consistently, ready for the next application, is obviously required. Although an
intermediate short spring might allow some tolerance.

Terry, East Grinstead, UK

Thanks all, rich seam of ideas to consider there!

BTW, no access to bypass the button, or I'd have gone that route. It's on a Polaroid
CUBE:
https://www.dropbox.com/s/q091oh3fpan8hwp/CUBE-2.jpg?raw=1

I'm going to revisit the solenoid, with damping initially and then maybe play with
PWM. But favourite is the servo, as the Arduino code is working for the first stage
of the project, pressing the button for 3 s to power up the CUBE. I'm looking
forward to getting off the PC and playing with linkage methods.

Size and weight are obvious factors. My servo's height to top of rotor is about 3
cm. Solenoid is four time larger and probably ten times heavier. CUBE is about 45 gm
and sides are 3 cm.

Prize for the most novel has to be the wax motor. But at 120/240V and with an
operating time measured in secs not ms, I think not.
https://www.youtube.com/watch?v=sApyrDEXGAI (try t ~ 4 mins).

Oh, I didn't realize this is what you wanted.

https://www.youtube.com/watch?v=3KTilOsXBmU

--

Rick C.

-- Get 1,000 miles of free Supercharging
-- Tesla referral code - https://ts.la/richard11209

 

[Jan Panteltje]

On a sunny day (Tue, 29 Oct 2019 06:18:23 -0700 (PDT)) it happened Rick C
<gnuarm.deletethisbit@gmail.com> wrote in
<21f9c98a-8fdf-42ca-88f2-cf0521d28b29@googlegroups.com>:

Oh, I didn't realize this is what you wanted.

https://www.youtube.com/watch?v=3KTilOsXBmU

That is fun ;-)

I was wondering if I had to solve it from the junk box
would take some old relay, normally energized,
then add a pin from the moving part, so when it is de-energized it pushes:

^
|
|
-----
/ | |
/ [ / ] coil
| | spring not drawn, not to scale
============

small distance, little force, hardly any noise,
Disadvantage powered when off.
Maybe latching relay...

 

is the plunger not pressed against the button when it is off? iow is it hitting the button instead of pressing the button?

+1

remove the dead space between the plunger and the button

m