On Thursday, 18 June 2020 09:21:30 UTC+1, Dave W wrote:
On Tue, 16 Jun 2020 14:05:31 -0700 (PDT), tabbypurr wrote:
On Tuesday, 16 June 2020 19:45:38 UTC+1, Dave W wrote:
On Tue, 16 Jun 2020 08:17:27 -0700 (PDT), tabbypurr wrote:
On Monday, 15 June 2020 23:17:35 UTC+1, Dave W wrote:
On Mon, 15 Jun 2020 13:38:13 -0700 (PDT), tabbypurr wrote:
On Monday, 15 June 2020 16:40:36 UTC+1, Brian Reay wrote:

We've got one of the old Friedland 'ding-dong' chimes- it was fitted
when we bought the house and, as strange is it seems, we love it.. It
isn't electronic, just a nice, pure, 'ding dong'. Plus, it works like a
Rolex- it just keeps going. I assumed for years it ran off transformer
until someone used it when the power was off and I don't recall even
even changing the batteries. We bought the house in 1997 so they've not
done badly. I do check they aren't corroding etc now I know it isn't
mains powered!

From the above, the reasons we'd like to keep the chime should be obvious.

I also don't want to mess around charging the battery in the Ring Unit
but, it seems, in theory, you can (sometimes) keep the old chime and
charge the Ring Unit- if you have a transformer bell which is compatible.

However, as Ring is really aimed at the US market, compatible for an
older chime seems to mean a chime than runs off a higher voltage than
many UK ones- including ours- the Ring wants 16-24VAC, our chime is more
like 8VAC as far as I can tell.

I've an idea how to solve this- a relay which runs of, say 18-24VAC
which the Ring 'sees' as the bell with the contacts acting as the bell
push for the existing chime, running off 8VAC.

Looking on the Internet, it seems others have done this and it works BUT
as I suspected, there is a problem. The resistance of the relays is
higher than bell coils so the standing current through the relay (to
charge the Ring battery, causes a problem. I suspected this - I'd
worked done some calculations using a best guess of the standing current
drawn by the Ring unit.

It seems this problem crops up elsewhere (not sure where) as Ring can
supply a 'box' which you would connect across the relay coil. (I assume
when used normally, ie not in 'work around' set ups, it would go across
the chime coil).

Said box obviously provides, in simple terms, an alternate current path
for the standing current to charge the Ring unit. I suspect it is no
more than a simple resistor, probably wire wound, able to handle the
power etc. Needless to say, the box has a fancy name the "Ring Pro Power
Kit".

I get the impression they supply these boxes free if you need one but
I'm not adverse to buying one- the Ring itself isn't cheap and a few
quid more for a box, especially as I need to buy other bits etc, isn't
an issue.

HOWEVER, I'd like to understand exacting what is in it, especially as
it seems I'm not using it quite as intended (even though someone else
has has the same idea and used the box etc.)

So, my question to the group, or at least anyone who has fitted a Ring
and used the "Ring Pro Power Kit"- What is in it? It seems to be
(about) the size of a large match box and has 2 wires.

You sure love ambiguity.

Assuming you're trying to run your friedland dingdong from a higher
voltage, the simplest solution is to put a big fat capacitor in series
with the friedland and feed that via a bridge rectifier from your
16-24v ac supply. Value required will need to be found by experiment,
I'd start with maybe 2,200uF and expect to need to go up from there..
24v ac is about 35v peak so the C must be rated at least 40v,
preferably 50v. Capacitor polarity is important of course.

FWLIW this also much reduces power consumption.


NT

That sounds like rubbish to me.

You didn't understand it

The Friedland requires DC to make it
ding,

it uses a solenoid so it doesn't much care if it gets ac or dc.

and then nothing to make it dong.

right

It runs off a battery, not 8V
AC as the OP seems to think. A big fat capacitor won't pass DC from a
bridge rectifier.

It does in fact pass a single pulse of current when dc is fed to it.


Perhaps you meant to say feed the Friedland from a bridge rectifier
which is driven by a big fat capacitor from 16-24V supply?

no

As the capacitor passes AC it would have to be an unpolarised type. Or
two 4700uF back to back to make 2200uf result.

it doesn't

I too can't understand the OP's post, or the Ring website with its
mysterious PowerPro unit. It seems to me that it just needs a 24V AC
relay driven by the Ring setup driven by its 24V transformer, and the
battery powered chime is connected to its contacts instead of the old
button.

There's a selection of options. I thought I'd mention a rather simpler one.


NT

Yea, quite right, I didn't understand it. Yes I was wrong thinking the
Friedland required DC. I now understand your posting - the capacitor
would send a pulse of current to the Friedland, but you'd need to
remove its battery and short across the terminals, so that current up
the bellpush terminals would ring the bell.

Now, I should think the coil resistance is about 10 ohms, (the
transformer is 8V 1A, or a 6V DC battery would pass a reasonable
600mA). Or might even be 5 ohms. To get a 1 second time constant with
10 ohms requires a capacitor of 100,000 uF. You need a long time
constant so that the dong doesn't happen until the caller releases the
button.

you don't need anything like that, just enough kick to get the plunger moving fast enough so it hits the ding. It'll hit its dong as soon as it mechinically can, the bellpush doesn't enter into that. 5-10 thousand uF should be fine, maybe less. Don't forget it's seeing well above its rated voltage which helps.


NT

Of course it will hit the ding, but then it will immediately fall back
to the dong.

yes, ie it works correctly That is how they work.