# Help needed designing simple circuit

N

#### [email protected]

Jan 1, 1970
0
(famous last words, "simple circuit" ...)

OK, so I'm trying to come up with a simple (maybe even elegant) solution
to a simple problem. Have an idea I want to run by y'all.

Function: person has a motion-detector light installed in their home.
They want a buzzer/bell/annunciator of some kind to go off *momentarily*
whenever the light is activated.

Here's my idea for the circuit:
http://www.geocities.com/bonezphoto/misc/One-shotBell.gif

First of all, please don't laugh at this. I am *not* a double-E or in
any way an electronics expert. Also keep in mind that this is the
farthest thing from a mil-spec application. It's just for fun; no life
support medical devices will depend on it.

I'd like to know the following:

1. Will this circuit even work?
1a. Will it work but end up destroying one or more components?
2. Is there a simpler way of accomplishing this task?
3. If it'll work, what are the right component values?

Explanation:

D1 is a half-wave rectifier. C2 filters the DC to produce more-or-less
ripple-free current. C1 provides the momentary "on" signal, by charging,
then "shutting down" when charged (sized according to RC time constant
to provide the desired "on" time). R2 and R3 form a voltage divider to
supply the appropriate base voltage to Q1. R1 acts as a voltage divider
in series with the load to supply the appropriate output voltage. (I
chose 24 volts DC arbitrarily; it might be less, probably not more.)

Component sizing:

R1 would obviously have to be large enough (in terms of power capacity)
to handle the load. The load would probably have a minimal current draw.
And since it would only be "on" momentarily, R1 could probably be a bit

Q1 would also need to be large enough to handle the load. I'm thinking a
common TO-220 type might work fine.

R2 & R3 could be small 1/8 watters.

OK, have at it. Rip 'er apart!

I thibk you may want to check the orientation od D1.

Based on that, this might be safer:

Go to http://www.x10.com/products/pr511_ed_deal.html

Replace existing motion sensor light.

Done.

D

#### David Nebenzahl

Jan 1, 1970
0
(famous last words, "simple circuit" ...)

OK, so I'm trying to come up with a simple (maybe even elegant) solution
to a simple problem. Have an idea I want to run by y'all.

Function: person has a motion-detector light installed in their home.
They want a buzzer/bell/annunciator of some kind to go off *momentarily*
whenever the light is activated.

Here's my idea for the circuit:
http://www.geocities.com/bonezphoto/misc/One-shotBell.gif

First of all, please don't laugh at this. I am *not* a double-E or in
any way an electronics expert. Also keep in mind that this is the
farthest thing from a mil-spec application. It's just for fun; no life
support medical devices will depend on it.

I'd like to know the following:

1. Will this circuit even work?
1a. Will it work but end up destroying one or more components?
2. Is there a simpler way of accomplishing this task?
3. If it'll work, what are the right component values?

Explanation:

D1 is a half-wave rectifier. C2 filters the DC to produce more-or-less
ripple-free current. C1 provides the momentary "on" signal, by charging,
then "shutting down" when charged (sized according to RC time constant
to provide the desired "on" time). R2 and R3 form a voltage divider to
supply the appropriate base voltage to Q1. R1 acts as a voltage divider
in series with the load to supply the appropriate output voltage. (I
chose 24 volts DC arbitrarily; it might be less, probably not more.)

Component sizing:

R1 would obviously have to be large enough (in terms of power capacity)
to handle the load. The load would probably have a minimal current draw.
And since it would only be "on" momentarily, R1 could probably be a bit

Q1 would also need to be large enough to handle the load. I'm thinking a
common TO-220 type might work fine.

R2 & R3 could be small 1/8 watters.

OK, have at it. Rip 'er apart!

--
Made From Pears: Pretty good chance that the product is at least
mostly pears.
Made With Pears: Pretty good chance that pears will be detectable in
the product.
Contains Pears: One pear seed per multiple tons of product.

(with apologies to Dorothy L. Sayers)

W

#### William Sommerwerck

Jan 1, 1970
0
(famous last words, "what does this post
have to do with electronics repair"...)

A lot... if the circuit damages something.

About 50 years ago, MAD ran a parody titled "Beatnik Magazine". One of its
contents was a photo of a middle-class family, watching TV in the living
room, with the caption "What's wrong with this picture?" The answer was
"Like, man, /everything/ is wrong with this picture."

That pretty applies to the circuit. I see what you're trying to do, but
you're going to get two exploded caps (at least), and possibly a small fire.

Take the other poster's advice. Buy a second detector and plug a 120V alarm
of some sort where the lamp goes. If the one you have an handle enough
current, you could always stick a plug adapter in the lamp socket.

P

#### petrus bitbyter

Jan 1, 1970
0
David Nebenzahl said:
(famous last words, "simple circuit" ...)

OK, so I'm trying to come up with a simple (maybe even elegant) solution
to a simple problem. Have an idea I want to run by y'all.

Function: person has a motion-detector light installed in their home.
They want a buzzer/bell/annunciator of some kind to go off *momentarily*
whenever the light is activated.

Here's my idea for the circuit:
http://www.geocities.com/bonezphoto/misc/One-shotBell.gif

First of all, please don't laugh at this. I am *not* a double-E or in any
way an electronics expert. Also keep in mind that this is the farthest
thing from a mil-spec application. It's just for fun; no life support
medical devices will depend on it.

I'd like to know the following:

1. Will this circuit even work?
1a. Will it work but end up destroying one or more components?
2. Is there a simpler way of accomplishing this task?
3. If it'll work, what are the right component values?

Explanation:

D1 is a half-wave rectifier. C2 filters the DC to produce more-or-less
ripple-free current. C1 provides the momentary "on" signal, by charging,
then "shutting down" when charged (sized according to RC time constant to
provide the desired "on" time). R2 and R3 form a voltage divider to supply
the appropriate base voltage to Q1. R1 acts as a voltage divider in series
with the load to supply the appropriate output voltage. (I chose 24 volts
DC arbitrarily; it might be less, probably not more.)

Component sizing:

R1 would obviously have to be large enough (in terms of power capacity) to
handle the load. The load would probably have a minimal current draw. And
since it would only be "on" momentarily, R1 could probably be a bit

Q1 would also need to be large enough to handle the load. I'm thinking a
common TO-220 type might work fine.

R2 & R3 could be small 1/8 watters.

OK, have at it. Rip 'er apart!

--
Made From Pears: Pretty good chance that the product is at least
mostly pears.
Made With Pears: Pretty good chance that pears will be detectable in
the product.
Contains Pears: One pear seed per multiple tons of product.

(with apologies to Dorothy L. Sayers)

It will not work at all and it'll take half a course in electronics to
explain why. I'm too tired to write that course.

petrus bitbyter

P

#### PlainBill

Jan 1, 1970
0
(famous last words, "simple circuit" ...)

OK, so I'm trying to come up with a simple (maybe even elegant) solution
to a simple problem. Have an idea I want to run by y'all.

Function: person has a motion-detector light installed in their home.
They want a buzzer/bell/annunciator of some kind to go off *momentarily*
whenever the light is activated.

Here's my idea for the circuit:
http://www.geocities.com/bonezphoto/misc/One-shotBell.gif

First of all, please don't laugh at this. I am *not* a double-E or in
any way an electronics expert. Also keep in mind that this is the
farthest thing from a mil-spec application. It's just for fun; no life
support medical devices will depend on it.

I'd like to know the following:

1. Will this circuit even work?
1a. Will it work but end up destroying one or more components?
2. Is there a simpler way of accomplishing this task?
3. If it'll work, what are the right component values?

Explanation:

D1 is a half-wave rectifier. C2 filters the DC to produce more-or-less
ripple-free current. C1 provides the momentary "on" signal, by charging,
then "shutting down" when charged (sized according to RC time constant
to provide the desired "on" time). R2 and R3 form a voltage divider to
supply the appropriate base voltage to Q1. R1 acts as a voltage divider
in series with the load to supply the appropriate output voltage. (I
chose 24 volts DC arbitrarily; it might be less, probably not more.)

Component sizing:

R1 would obviously have to be large enough (in terms of power capacity)
to handle the load. The load would probably have a minimal current draw.
And since it would only be "on" momentarily, R1 could probably be a bit

Q1 would also need to be large enough to handle the load. I'm thinking a
common TO-220 type might work fine.

R2 & R3 could be small 1/8 watters.

OK, have at it. Rip 'er apart!

Reversing D1 and providing a bleeder resistor across C2 have already
been mentioned. I have two further suggestions.

1. Either provide a diode to prevent the base of Q1 going too far
negative with respect to it's emitter or size the bleeder resistor
(R4) so the time constant of C2-R4 is much greater than the time
constant of C1-R2+R3
2. Choose R1 to provide about a 140V drop across R1 at the buzzer's
rated current. Place a zener diode across the 24VDC terminals to
prevent excessive current flow through the buzzer.

Contrary to what several nay-sayers have expressed, this exercise has
a LOT to do with electronics repair. Any fool can keep replacing
components until he finds the bad one. The successful tech will be
able to analyse a circuit and make meaningful tests to identfy the
failing part.

NOW your next exercise is to identify the values for these components.

PlainBill

D

#### David Nebenzahl

Jan 1, 1970
0
Actually the circuit is not all that unworkable. Some

1) Diode D1 is backwards;
2) You need a resistor in series with D1 to limit in-rush
current;
3) There is no discharge path for C1. A high value resistor
across C2 can fix that;
4) What do expect to place across the terminals labeled 24
VDC? The voltage there may have no relation to 24 volts.

Further suggestions contingent upon knowing what is at the
24 VDC connection.

Thank you for not automatically dismissing the whole thing out of hand,
as other respondents obviously did. Not helpful.

1. Yeah, it's a *drawing* error. I can still not remember which way is
which, graphically speaking, for the life of me. When I actually build
stuff I check and double-check diode anode-cathode connections, and
haven't gotten it wrong once. I guess I just need a good mnemonic to
remember which way the damn arrow points.

2. OK; I presume this needs to be the same size (power capacity) as the
resistor in series with the load, right?

3. OK.

4, 5: The load would be a small annunciator device: a doorbell, chime or
other sound-generating device, *probably* operating at 18-24 volts. I'm
guessing current draw would be in the low hundreds of mA, certainly less
than half an amp. Does that help?

--
Made From Pears: Pretty good chance that the product is at least
mostly pears.
Made With Pears: Pretty good chance that pears will be detectable in
the product.
Contains Pears: One pear seed per multiple tons of product.

(with apologies to Dorothy L. Sayers)

D

#### David Nebenzahl

Jan 1, 1970
0
Actually the circuit is not all that unworkable. Some

Check the updated schematic, incorporating your suggestions:
http://www.geocities.com/bonezphoto/misc/One-shotBell.gif

Let me know what you think.

--
Made From Pears: Pretty good chance that the product is at least
mostly pears.
Made With Pears: Pretty good chance that pears will be detectable in
the product.
Contains Pears: One pear seed per multiple tons of product.

(with apologies to Dorothy L. Sayers)

D

#### David Nebenzahl

Jan 1, 1970
0
Thank you for not automatically dismissing the whole thing out of hand,
as other respondents obviously did. Not helpful.

1. Yeah, it's a *drawing* error. I can still not remember which way is
which, graphically speaking, for the life of me. When I actually build
stuff I check and double-check diode anode-cathode connections, and
haven't gotten it wrong once. I guess I just need a good mnemonic to
remember which way the damn arrow points.

2. OK; I presume this needs to be the same size (power capacity) as the
resistor in series with the load, right?

3. OK.

4, 5: The load would be a small annunciator device: a doorbell, chime or
other sound-generating device, *probably* operating at 18-24 volts. I'm
guessing current draw would be in the low hundreds of mA, certainly less
than half an amp. Does that help?

-- Made From Pears: Pretty good chance that the product is at least
mostly pears. Made With Pears: Pretty good chance that pears will be
detectable in the product. Contains Pears: One pear seed per multiple
tons of product. (with apologies to Dorothy L. Sayers)

D

#### David Nebenzahl

Jan 1, 1970
0
Actually the circuit is not all that unworkable. Some

1) Diode D1 is backwards;
2) You need a resistor in series with D1 to limit in-rush
current;
3) There is no discharge path for C1. A high value resistor
across C2 can fix that;
4) What do expect to place across the terminals labeled 24
VDC? The voltage there may have no relation to 24 volts.

Further suggestions contingent upon knowing what is at the
24 VDC connection.

Thank you for not automatically dismissing the whole thing out of hand,
as other respondents obviously did. Not helpful.

1. Yeah, it's a *drawing* error. I can still not remember which way is
which, graphically speaking, for the life of me. When I actually build
stuff I check and double-check diode anode-cathode connections, and
haven't gotten it wrong once. I guess I just need a good mnemonic to
remember which way the damn arrow points.

2. OK; I presume this needs to be the same size (power capacity) as the
resistor in series with the load, right?

3. OK.

4, 5: The load would be a small annunciator device: a doorbell, chime or
other sound-generating device, *probably* operating at 18-24 volts. I'm
guessing current draw would be in the low hundreds of mA, certainly less
than half an amp. Does that help?

--
Made From Pears: Pretty good chance that the product is at least
mostly pears.
Made With Pears: Pretty good chance that pears will be detectable in
the product.
Contains Pears: One pear seed per multiple tons of product.

(with apologies to Dorothy L. Sayers)

W

#### William Sommerwerck

Jan 1, 1970
0
Further suggestions contingent upon knowing what is at the
Thank you for not automatically dismissing the whole thing out
of hand, as other respondents obviously did. Not helpful.

What are we supposed to do? Be a free design service for someone with little
understanding of electronics?

I can see what's going to happen. You're going to build something, and when
it doesn't work, bring it back here over and over for troubleshooting
assistance.

This is not the way to learn electronics Find some books on electronics and
start reading.. Buy one of those 100-in-1 lab kits and have some fun.

Let me give a parallel example. Suppose you'd written the first chapter of a
crappy novel. Would you expect other people to guide you through the process
of editing it, and teaching you how to write, simply because they have
nothing better to do with their time?

D

#### David Nebenzahl

Jan 1, 1970
0
and thank you for not multiple posting
and thank you for not multiple posting
and thank you for not multiple posting
and thank you for not multiple posting
and thank you for not multiple posting
and thank you for not multiple postilg

Sorry 'bout that: for some reason, my posts haven't been "getting
through" here lately (had to post the original message twice to have it
show up here at all).

--
Made From Pears: Pretty good chance that the product is at least
mostly pears.
Made With Pears: Pretty good chance that pears will be detectable in
the product.
Contains Pears: One pear seed per multiple tons of product.

(with apologies to Dorothy L. Sayers)

D

#### David Nebenzahl

Jan 1, 1970
0
Contrary to what several nay-sayers have expressed, this exercise has
a LOT to do with electronics repair. Any fool can keep replacing
components until he finds the bad one. The successful tech will be
able to analyse a circuit and make meaningful tests to identfy the
failing part.

Thank you. It's more than a little annoying being completely written off
as a clueless idiot simply because I reversed a diode's polarity *in a
schematic* (since corrected).
NOW your next exercise is to identify the values for these components.

I'd love to oblige you; unfortunately, I'm not yet at that level. I know
Ohm's law and some other basic stuff, but not enough about circuit
design to assign values with any confidence. I look forward to others
doing that. And someday, I intend to get a good basic electronics
textbook and seriously study it ...

--
Made From Pears: Pretty good chance that the product is at least
mostly pears.
Made With Pears: Pretty good chance that pears will be detectable in
the product.
Contains Pears: One pear seed per multiple tons of product.

(with apologies to Dorothy L. Sayers)

P

#### PlainBill

Jan 1, 1970
0
Thank you. It's more than a little annoying being completely written off
as a clueless idiot simply because I reversed a diode's polarity *in a
schematic* (since corrected).

I'd love to oblige you; unfortunately, I'm not yet at that level. I know
Ohm's law and some other basic stuff, but not enough about circuit
design to assign values with any confidence. I look forward to others
doing that. And someday, I intend to get a good basic electronics
textbook and seriously study it ...

Several comments on this circuit. First of all, it could work, but
would require significant improvements, some of which have already
been discussed. Rather than using a doorbell or chime, a Sonalert
could be used. In part this will depend on the sound level desired.

Second, some of the criticisms are valid. If you intend to do this as
a design exercise you can have fun designing it, but I would not
recommend building it. You are dealing with potentially lethal
voltages, and fairly expensive components to withstand those voltages.

IMHO, you are using the wrong approach. Over 30 years ago I built
something similar using a few small caps, a few resistors, a diode, a
speaker, and a 74C914 hex schmidt trigger. I used 4 AA cells to power
it, your application should use a 'wall wart' putting out 6VDC at 100
ma. I'd have to look up the specs, but a 555 timer would also do the
job.

PlainBill

D

#### David Nebenzahl

Jan 1, 1970
0
Several comments on this circuit. First of all, it could work, but
would require significant improvements, some of which have already
been discussed. Rather than using a doorbell or chime, a Sonalert
could be used. In part this will depend on the sound level desired.

So what improvements would you suggest to the current circuit (after I
made the changes recommended earlier)? (Circuit at
http://www.geocities.com/bonezphoto/misc/One-shotBell.gif)
Second, some of the criticisms are valid. If you intend to do this as
a design exercise you can have fun designing it, but I would not
recommend building it. You are dealing with potentially lethal
voltages, and fairly expensive components to withstand those voltages.

To be honest, I think it's more fun designing things like this that will
operate "directly" off line voltage (i.e., without a transformer). One
of the criteria of this whole deal was to avoid the use of a transformer.

And in defense of that, there are tons of things in use every day that
operate just this way. Latest example I found were a bunch of electric
staple guns a neighbor gave me that operated directly off 120 volts,
firing a solenoid through a capacitor.

If I were to actually build this, I'm confident I could do it safely--at
least as safely as those staple guns, which have UL, CSA, etc., compliance.

And what components would be expensive? Seems to me the most expensive
part would be the transistor, or possibly the two power resistors, but
even those aren't terribly pricey.
IMHO, you are using the wrong approach. Over 30 years ago I built
something similar using a few small caps, a few resistors, a diode, a
speaker, and a 74C914 hex schmidt trigger. I used 4 AA cells to power
it, your application should use a 'wall wart' putting out 6VDC at 100
ma. I'd have to look up the specs, but a 555 timer would also do the
job.

Could do, but see above.

--
Made From Pears: Pretty good chance that the product is at least
mostly pears.
Made With Pears: Pretty good chance that pears will be detectable in
the product.
Contains Pears: One pear seed per multiple tons of product.

(with apologies to Dorothy L. Sayers)

S

#### [email protected]

Jan 1, 1970
0
So what improvements would you suggest to the current circuit (after I
made the changes recommended earlier)? (Circuit athttp://www.geocities.com/bonezphoto/misc/One-shotBell.gif)

To be honest, I think it's more fun designing things like this that will
operate "directly" off line voltage (i.e., without a transformer). One
of the criteria of this whole deal was to avoid the use of a transformer.

And in defense of that, there are tons of things in use every day that
operate just this way. Latest example I found were a bunch of electric
staple guns a neighbor gave me that operated directly off 120 volts,
firing a solenoid through a capacitor.

If I were to actually build this, I'm confident I could do it safely--at
least as safely as those staple guns, which have UL, CSA, etc., compliance.

And what components would be expensive? Seems to me the most expensive
part would be the transistor, or possibly the two power resistors, but
even those aren't terribly pricey.

Could do, but see above.

--
Made From Pears: Pretty good chance that the product is at least
mostly pears.
Made With Pears: Pretty good chance that pears will be detectable in
the product.
Contains Pears:  One pear seed per multiple tons of product.

(with apologies to Dorothy L. Sayers)

And a relay won't do what you want? In theory, IF you get the
component values right AND the hot / neutral are as expected it COULD
work but I CERTAINLY would NOT allow that kind of mess in my house.

If you're going to dabble, do it at low voltages and transformer
isolated so you don't blow up stuff OR yourself.

Sorry to rain on your parade but at least you're alive to be pissed at
me.

B

#### Baron

Jan 1, 1970
0
David Nebenzahl Inscribed thus:
To be honest, I think it's more fun designing things like this that
will operate "directly" off line voltage (i.e., without a
transformer). One of the criteria of this whole deal was to avoid the
use of a transformer.

And in defense of that, there are tons of things in use every day that
operate just this way. Latest example I found were a bunch of electric
staple guns a neighbor gave me that operated directly off 120 volts,
firing a solenoid through a capacitor.

If I were to actually build this, I'm confident I could do it
safely--at least as safely as those staple guns, which have UL, CSA,
etc., compliance.

With all due respect I doubt it !

If you really look closely at the sort of products you mention, and I
could mention many more, they are all constructed in such a way that it
would be very difficult if not impossible for you to be able to touch
any part that would allow you to come into contact with the mains !

By doing what you are wanting to do, and I am not saying "Don't", you
are potentially putting yourself and others at risk of electric shock,
not to mention any other possible hazards.

I personally would want to ensure that I didn't introduce any potential
hazard that could endanger my family, myself or any visitors !

A small relay would do what you want and provide isolation from the
mains supply.

P

#### PlainBill

Jan 1, 1970
0
So what improvements would you suggest to the current circuit (after I
made the changes recommended earlier)? (Circuit at
http://www.geocities.com/bonezphoto/misc/One-shotBell.gif)
You must add surge supression if you are using an inductive load.
Without it, the pulse generated when the transistor turns off will
eventually destroy it.
To be honest, I think it's more fun designing things like this that will
operate "directly" off line voltage (i.e., without a transformer). One
of the criteria of this whole deal was to avoid the use of a transformer.

And in defense of that, there are tons of things in use every day that
operate just this way. Latest example I found were a bunch of electric
staple guns a neighbor gave me that operated directly off 120 volts,
firing a solenoid through a capacitor.

If I were to actually build this, I'm confident I could do it safely--at
least as safely as those staple guns, which have UL, CSA, etc., compliance.

And what components would be expensive? Seems to me the most expensive
part would be the transistor, or possibly the two power resistors, but
even those aren't terribly pricey.
Cost would depend on the nature of the load. If you are using a

On the other hand, if you are using a chime the load will be higher,
and using a doorbell REALLY opens a can of worms. I think you had
better expect a load of .5A, and one heck of an inductive kick as the
transistor turns off. The typical doorbell is designed to operate on
about 15VAC. I would expect rater short contact life if you run it
off DC.

Could do, but see above.

PlainBill

T

#### Tim

Jan 1, 1970
0
(famous last words, "simple circuit" ...)

OK, so I'm trying to come up with a simple (maybe even elegant) solution
to a simple problem. Have an idea I want to run by y'all.

Function: person has a motion-detector light installed in their home.
They want a buzzer/bell/annunciator of some kind to go off *momentarily*
whenever the light is activated.

Here's my idea for the circuit:
http://www.geocities.com/bonezphoto/misc/One-shotBell.gif

First of all, please don't laugh at this. I am *not* a double-E or in
any way an electronics expert. Also keep in mind that this is the
farthest thing from a mil-spec application. It's just for fun; no life
support medical devices will depend on it.

I'd like to know the following:

1. Will this circuit even work?
1a. Will it work but end up destroying one or more components?
2. Is there a simpler way of accomplishing this task?
3. If it'll work, what are the right component values?

Explanation:

D1 is a half-wave rectifier. C2 filters the DC to produce more-or-less
ripple-free current. C1 provides the momentary "on" signal, by charging,
then "shutting down" when charged (sized according to RC time constant
to provide the desired "on" time). R2 and R3 form a voltage divider to
supply the appropriate base voltage to Q1. R1 acts as a voltage divider
in series with the load to supply the appropriate output voltage. (I
chose 24 volts DC arbitrarily; it might be less, probably not more.)

Component sizing:

R1 would obviously have to be large enough (in terms of power capacity)
to handle the load. The load would probably have a minimal current draw.
And since it would only be "on" momentarily, R1 could probably be a bit

Q1 would also need to be large enough to handle the load. I'm thinking a
common TO-220 type might work fine.

R2 & R3 could be small 1/8 watters.

OK, have at it. Rip 'er apart!
OK, so a lot of issues here deal with the AC power being detected and
transferred to something useful. I did a simple data logger for my well
pump (URL: http://personal.nbnet.nb.ca/snowowl/DataRecorder.html), that
had to deal 220V being sensed. I used a cheap little cell phone / palm
pilot charger that was universal 110/220 50/60hz and wired it parallel
with the motor leads. This gave me a nice 5 volts when the power was
applied to the pump, so I could log it's on cycles. You still have to
wire it up the the light, so that's a danger here as well. Dealing with
AC mains wiring, there always a need for extra safety.

- Tim -

D

#### David Nebenzahl

Jan 1, 1970
0
OK, so a lot of issues here deal with the AC power being detected and
transferred to something useful. I did a simple data logger for my well
pump (URL: http://personal.nbnet.nb.ca/snowowl/DataRecorder.html), that
had to deal 220V being sensed. I used a cheap little cell phone / palm
pilot charger that was universal 110/220 50/60hz and wired it parallel
with the motor leads. This gave me a nice 5 volts when the power was
applied to the pump, so I could log it's on cycles. You still have to
wire it up the the light, so that's a danger here as well. Dealing with
AC mains wiring, there always a need for extra safety.

Unfortunately, your solution, while interesting, misses one of the
requirements of the whole deal: it needs to operate the
bell/chime/annunciator *momentarily*, not continuously.

--
Made From Pears: Pretty good chance that the product is at least
mostly pears.
Made With Pears: Pretty good chance that pears will be detectable in
the product.
Contains Pears: One pear seed per multiple tons of product.

(with apologies to Dorothy L. Sayers)

B

#### Baron

Jan 1, 1970
0
I think that a small sugar cube relay, diode, resistor and capacitor
will do the job !

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