Reply by RheillyPhoull●November 25, 20202020-11-25
On 25/11/2020 5:55 pm, RobH wrote:
> On 25/11/2020 09:40, Jeroen Belleman wrote:
>> On 2020-11-25 09:10, Phil Hobbs wrote:
>>> On 11/24/20 4:54 PM, Jeroen Belleman wrote:
>>>
>>>>
>>>> For an older electronics professional, it is sometimes good to
>>>> be reminded how many errors a beginner can make. I had your
>>>> problems fifty years ago. (No, I didn't have 555s then.)
>>>
>>> And you had to make protons go round and round in mason jars. ;)
>>>
>>> Cheers
>>>
>>> Phil Hobbs
>>>
>>> "In my day, we defragged hard disks by editing the inodes by hand.
>>> With magnets"
>>>
>>>
>>
>> In those days, I had no idea that one could become a 'physicist'.
>> There were no engineers or academics in my environment, or my
>> choices might have been quite different. I discovered the very
>> existence of labs dedicated to physics research when I was 19
>> years old, quite accidentally as a side effect of my negligence
>> to secure a local position as a technical student. It turned out
>> to be a lucky strike. :-)
>>
>> Jeroen Belleman
>
> Aah, well I was a mechanical engineer for over 40 years, and I can read
> drawings including schematics. I can't draw tho'.
Yup, I think we can all agree on that one :-)
Reply by amdx●November 25, 20202020-11-25
On 11/22/2020 7:05 AM, RobH wrote:
> I built an alarm circuit from a book I bought called Make Electronics
> by Charles Platt.
>
> https://drive.google.com/file/d/1NxvKdZCqykuSjBvPVoWz_MEMhKYMMz9E/view?usp=sharing
>
>
> The said circuit produces a siren type sound on a buzzer so I added
> an led through a resistor, a 10k pot and a LDR. I then connected the
> centre pin of the 10k pot to pin 2 on the top IC555 shown on the
> schematic
>
>
> Working version of the circuit
> https://drive.google.com/file/d/1NwYnNkljKLd7ORmZ16VYrtb7ZwCsvAn_/view?usp=sharing
>
>
> As the said circuit was working as I wanted with the ldr and buzzer, I
> built another of the same circuit.
>
> On this 2nd circuit, the led goes off when I adjust the 10k pot, but
> the sound does not. It does on the first circuit I built.
>
> Thanks
I'll take a stab at it. But I'm making a guess without looking closer.
Looking at this layout,
The top 555 has a slow on/off rate, the slow square wave controls the
bottom 555 that has a fast
fast on/off rate (frequency). From your description you want the sound
to go quiet when light hits the LDR.
The best way to make the sound stop is to hold pin 2 of the bottom 555
high. Try that, put a 470 Ω resistor from
+ to pin 2 of the bottom 555. If the sound doe not stop, try 100 Ω.
Does the sound stop?
If it does, then you need to make a circuit to pull that pin 2 high
when their is light.
Sometime in your previous experiments you had an LDR wired to a 555 that
would make pin 3 go high
when there was light. That would rewire a 3rd 555. Can you just wire an
LDR to pin 2 of the bottom 555,
maybe, with some resistor changes.
Mikek
--
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Reply by Rich●November 25, 20202020-11-25
RobH <rob@despammer.com> wrote:
> On 25/11/2020 11:37, Jeroen Belleman wrote:
>> On 2020-11-25 10:19, RobH wrote:
>>> On 25/11/2020 04:42, Rich wrote:
>> [...]
>>
>>>>
>>>> The question was quite clear, but perhaps you missed it, so I'll
>>>> repeat it below:
>>>>
>>>>> Are you using bipolar 555's or CMOS 555's?
>> [...]
>>>
>>> Is this any clearer:
>>>
>>> https://drive.google.com/file/d/1PL_AeVMofix5-WLABwicplR49_bNAyrj/view?usp=sharing
>>>
>>>
>>> �If it's not then , I'll just forget about it, as it was only
>>> something I wanted to do while in lockdown.
>>>
>>> I didn't miss your question about the 555's as I answered you:
>>>
>>> As I said in my OP I built the circuit from an article in a book I
>>> bought several months ago, and it doesn't say to use CMOS 555's or
>>> bipolar 555's, but just 555's.
>>>
>>> In case you missed my� OP, I already built the said circuit
>>> previously and have it working fine.
>>
>> This is becoming a 'dialogue de sourds'. The question was
>> "Are you using bipolar 555's or CMOS 555's?". You did *not*
>> answer that question. Just give us the exact type as read
>> from the actual DIP you have in there!
>>
>> You still haven't explained what the intended effect of
>> the added components is. How are we to know what it is
>> *supposed* to do?
>>
>> Your picture still leaves much to be desired, hiding several
>> crucial details. One thing is clear though: The potentiometer
>> will have little or no effect until it reaches either end.
>>
>> If the LED lights at all, it will likely be full on or full
>> off with the potentiometer at either end, and perhaps blink
>> for intermediate settings. Even so, this abuses the 555, the
>> potentiometer and the 9V battery. You seem to be trying to
>> overpower the 555's output with the centre tap of the
>> potentiometer.
>>
>> Jeroen Belleman
>>
>
> From my OP:
> The said circuit produces a siren type sound on a buzzer so I added an
> led through a resistor, a 10k pot and a LDR.
>
> So when light hits the LDR, the alarm goes off.
Three days in, 21 articles, and only *now* do you actually state why
you added the extra components. Your OP three days ago left off the
"So when ... off." sentence.
Reply by Rich●November 25, 20202020-11-25
RobH <rob@despammer.com> wrote:
> On 25/11/2020 04:42, Rich wrote:
>> RobH <rob@despammer.com> wrote:
>>> On 24/11/2020 16:43, Rich wrote:
>>>> However, your new schematic above does *not* show the center pin of
>>>> the 10k pot connected to pin 2 of the top 555. It shows the center
>>>> pin of the 10k pot connected to the positive voltage rail, and the
>>>> positive voltage rail connected to pin 2 of the 555. Note also that
>>>> your annotations are wrong. You have the line to pin 2 annotated as
>>>> "to pin 3" and the wire to pin 3 annotated as "to pin 2".
>>>>
>>>> So, either your textual description is wrong, or your new schematic
>>>> drawing additions are wrong. But you can't expect anyone here to be
>>>> of much help when you provide incorrect information at the outset.
>>>>
>>> Oops, apologies for the error in the previous schematic of added parts.
>>> I have corrected it now:
>>
>> Are you sure you have. Your new schematic photo now shows a dead short
>> between the positive and negative power rails, and does not show three
>> pins on the 10k pot (so no center pin connected anywhere.
>>
>>>> Also, your schematic shows no bypass capacitors for the 555's. You've
>>>> left out another critical bit of information. Are you using bipolar
>>>> 555's or CMOS 555's? Because if you are using bipolar 555's, you'll
>>>> very much want to add bypass cap's across the 555 power rails.
>>>
>>> As I said in my OP I built the circuit from an article in a book I
>>> bought several months ago, and it doesn't say to use CMOS 555's or
>>> bipolar 555's, but just 555's.
>>
>> The question was quite clear, but perhaps you missed it, so I'll repeat
>> it below:
>>
>>> Are you using bipolar 555's or CMOS 555's?
>>
>>> https://drive.google.com/file/d/1O4LWsY41SLjjMaRgLAbh7kONCRkAx9LR/view?usp=sharing
>>>>
>>>> Also, another tip, when positing schematic pictures here asking for
>>>> help, it is best to add numbers to all the components (i.e., R1, R2,
>>>> C1, C2, U1, U2, ...). That helps you and us have a common nomenclature
>>>> with which to refer to specific items on the schematics.
>>>>
>>>
>>> I've named the added 320 ohm resistor as R1, and both the led and the
>>> 10k pot centre pin is connected to pin 3 on the 555
>>>
>>> https://drive.google.com/file/d/1OyIH7dWiGtX08ytolqDMsCqT-tQxg8nz/view?usp=sharing
>>
>> This schematic shows only two of three pins of the pot (presumably you
>> have a three pin pot, as you did begin with "center pin of pot
>> connected..."
>>
>> But with the dead short in this version across the power rails (if the
>> schematic matches how you have it wired), all you will achieve from
>> this version is warming up your power supply (or blowing it up,
>> depending on whether it tolerates a dead short).
>>
>
> Is this any clearer:
>
> https://drive.google.com/file/d/1PL_AeVMofix5-WLABwicplR49_bNAyrj/view?usp=sharing
No. A photo of your breadboard is not *clearer* -- in fact it is
almost worse than having nothing at all.
> If it's not then , I'll just forget about it, as it was only something I
> wanted to do while in lockdown.
>
> I didn't miss your question about the 555's as I answered you:
>
> As I said in my OP I built the circuit from an article in a book I
> bought several months ago, and it doesn't say to use CMOS 555's or
> bipolar 555's, but just 555's.
>
> In case you missed my OP, I already built the said circuit previously
> and have it working fine.
And you have still avoided *actually answering the question*. There
are three proper answers:
1) I am using bipolar 555's
2) I am using CMOS 555's
3) I don't know, the numbers on the top of the chips are: .........
Reply by RobH●November 25, 20202020-11-25
On 25/11/2020 11:37, Jeroen Belleman wrote:
> On 2020-11-25 10:19, RobH wrote:
>> On 25/11/2020 04:42, Rich wrote:
> [...]
>
>>>
>>> The question was quite clear, but perhaps you missed it, so I'll
>>> repeat it below:
>>>
>>>> Are you using bipolar 555's or CMOS 555's?
> [...]
>>
>> Is this any clearer:
>>
>> https://drive.google.com/file/d/1PL_AeVMofix5-WLABwicplR49_bNAyrj/view?usp=sharing
>>
>>
>> If it's not then , I'll just forget about it, as it was only
>> something I wanted to do while in lockdown.
>>
>> I didn't miss your question about the 555's as I answered you:
>>
>> As I said in my OP I built the circuit from an article in a book I
>> bought several months ago, and it doesn't say to use CMOS 555's or
>> bipolar 555's, but just 555's.
>>
>> In case you missed my OP, I already built the said circuit
>> previously and have it working fine.
>
> This is becoming a 'dialogue de sourds'. The question was
> "Are you using bipolar 555's or CMOS 555's?". You did *not*
> answer that question. Just give us the exact type as read
> from the actual DIP you have in there!
>
> You still haven't explained what the intended effect of
> the added components is. How are we to know what it is
> *supposed* to do?
>
> Your picture still leaves much to be desired, hiding several
> crucial details. One thing is clear though: The potentiometer
> will have little or no effect until it reaches either end.
>
> If the LED lights at all, it will likely be full on or full
> off with the potentiometer at either end, and perhaps blink
> for intermediate settings. Even so, this abuses the 555, the
> potentiometer and the 9V battery. You seem to be trying to
> overpower the 555's output with the centre tap of the
> potentiometer.
>
> Jeroen Belleman
>
From my OP:
The said circuit produces a siren type sound on a buzzer so I added an
led through a resistor, a 10k pot and a LDR.
So when light hits the LDR, the alarm goes off.
Again, the same or earlier circuit works fine so I'll just leave it at
than now.
Thanks
Reply by Jeroen Belleman●November 25, 20202020-11-25
On 2020-11-25 10:19, RobH wrote:
> On 25/11/2020 04:42, Rich wrote:
[...]
>>
>> The question was quite clear, but perhaps you missed it, so I'll
>> repeat it below:
>>
>>> Are you using bipolar 555's or CMOS 555's?
[...]
>
> Is this any clearer:
>
> https://drive.google.com/file/d/1PL_AeVMofix5-WLABwicplR49_bNAyrj/view?usp=sharing
>
> If it's not then , I'll just forget about it, as it was only
> something I wanted to do while in lockdown.
>
> I didn't miss your question about the 555's as I answered you:
>
> As I said in my OP I built the circuit from an article in a book I
> bought several months ago, and it doesn't say to use CMOS 555's or
> bipolar 555's, but just 555's.
>
> In case you missed my OP, I already built the said circuit
> previously and have it working fine.
This is becoming a 'dialogue de sourds'. The question was
"Are you using bipolar 555's or CMOS 555's?". You did *not*
answer that question. Just give us the exact type as read
from the actual DIP you have in there!
You still haven't explained what the intended effect of
the added components is. How are we to know what it is
*supposed* to do?
Your picture still leaves much to be desired, hiding several
crucial details. One thing is clear though: The potentiometer
will have little or no effect until it reaches either end.
If the LED lights at all, it will likely be full on or full
off with the potentiometer at either end, and perhaps blink
for intermediate settings. Even so, this abuses the 555, the
potentiometer and the 9V battery. You seem to be trying to
overpower the 555's output with the centre tap of the
potentiometer.
Jeroen Belleman
Reply by RobH●November 25, 20202020-11-25
On 25/11/2020 09:40, Jeroen Belleman wrote:
> On 2020-11-25 09:10, Phil Hobbs wrote:
>> On 11/24/20 4:54 PM, Jeroen Belleman wrote:
>>
>>>
>>> For an older electronics professional, it is sometimes good to
>>> be reminded how many errors a beginner can make. I had your
>>> problems fifty years ago. (No, I didn't have 555s then.)
>>
>> And you had to make protons go round and round in mason jars. ;)
>>
>> Cheers
>>
>> Phil Hobbs
>>
>> "In my day, we defragged hard disks by editing the inodes by hand.
>> With magnets"
>>
>>
>
> In those days, I had no idea that one could become a 'physicist'.
> There were no engineers or academics in my environment, or my
> choices might have been quite different. I discovered the very
> existence of labs dedicated to physics research when I was 19
> years old, quite accidentally as a side effect of my negligence
> to secure a local position as a technical student. It turned out
> to be a lucky strike. :-)
>
> Jeroen Belleman
Aah, well I was a mechanical engineer for over 40 years, and I can read
drawings including schematics. I can't draw tho'.
Reply by Jeroen Belleman●November 25, 20202020-11-25
On 2020-11-25 09:10, Phil Hobbs wrote:
> On 11/24/20 4:54 PM, Jeroen Belleman wrote:
>
>>
>> For an older electronics professional, it is sometimes good to
>> be reminded how many errors a beginner can make. I had your
>> problems fifty years ago. (No, I didn't have 555s then.)
>
> And you had to make protons go round and round in mason jars. ;)
>
> Cheers
>
> Phil Hobbs
>
> "In my day, we defragged hard disks by editing the inodes by hand. With magnets"
>
>
In those days, I had no idea that one could become a 'physicist'.
There were no engineers or academics in my environment, or my
choices might have been quite different. I discovered the very
existence of labs dedicated to physics research when I was 19
years old, quite accidentally as a side effect of my negligence
to secure a local position as a technical student. It turned out
to be a lucky strike. :-)
Jeroen Belleman
Reply by RobH●November 25, 20202020-11-25
On 25/11/2020 04:42, Rich wrote:
> RobH <rob@despammer.com> wrote:
>> On 24/11/2020 16:43, Rich wrote:
>>> However, your new schematic above does *not* show the center pin of
>>> the 10k pot connected to pin 2 of the top 555. It shows the center
>>> pin of the 10k pot connected to the positive voltage rail, and the
>>> positive voltage rail connected to pin 2 of the 555. Note also that
>>> your annotations are wrong. You have the line to pin 2 annotated as
>>> "to pin 3" and the wire to pin 3 annotated as "to pin 2".
>>>
>>> So, either your textual description is wrong, or your new schematic
>>> drawing additions are wrong. But you can't expect anyone here to be
>>> of much help when you provide incorrect information at the outset.
>>>
>> Oops, apologies for the error in the previous schematic of added parts.
>> I have corrected it now:
>
> Are you sure you have. Your new schematic photo now shows a dead short
> between the positive and negative power rails, and does not show three
> pins on the 10k pot (so no center pin connected anywhere.
>
>>> Also, your schematic shows no bypass capacitors for the 555's. You've
>>> left out another critical bit of information. Are you using bipolar
>>> 555's or CMOS 555's? Because if you are using bipolar 555's, you'll
>>> very much want to add bypass cap's across the 555 power rails.
>>
>> As I said in my OP I built the circuit from an article in a book I
>> bought several months ago, and it doesn't say to use CMOS 555's or
>> bipolar 555's, but just 555's.
>
> The question was quite clear, but perhaps you missed it, so I'll repeat
> it below:
>
>> Are you using bipolar 555's or CMOS 555's?
>
>> https://drive.google.com/file/d/1O4LWsY41SLjjMaRgLAbh7kONCRkAx9LR/view?usp=sharing
>>>
>>> Also, another tip, when positing schematic pictures here asking for
>>> help, it is best to add numbers to all the components (i.e., R1, R2,
>>> C1, C2, U1, U2, ...). That helps you and us have a common nomenclature
>>> with which to refer to specific items on the schematics.
>>>
>>
>> I've named the added 320 ohm resistor as R1, and both the led and the
>> 10k pot centre pin is connected to pin 3 on the 555
>>
>> https://drive.google.com/file/d/1OyIH7dWiGtX08ytolqDMsCqT-tQxg8nz/view?usp=sharing
>
> This schematic shows only two of three pins of the pot (presumably you
> have a three pin pot, as you did begin with "center pin of pot
> connected..."
>
> But with the dead short in this version across the power rails (if the
> schematic matches how you have it wired), all you will achieve from
> this version is warming up your power supply (or blowing it up,
> depending on whether it tolerates a dead short).
>
Is this any clearer:
https://drive.google.com/file/d/1PL_AeVMofix5-WLABwicplR49_bNAyrj/view?usp=sharing
If it's not then , I'll just forget about it, as it was only something I
wanted to do while in lockdown.
I didn't miss your question about the 555's as I answered you:
As I said in my OP I built the circuit from an article in a book I
bought several months ago, and it doesn't say to use CMOS 555's or
bipolar 555's, but just 555's.
In case you missed my OP, I already built the said circuit previously
and have it working fine.
Thanks anyway
Reply by Phil Hobbs●November 25, 20202020-11-25
On 11/24/20 4:54 PM, Jeroen Belleman wrote:
>
> For an older electronics professional, it is sometimes good to
> be reminded how many errors a beginner can make. I had your
> problems fifty years ago. (No, I didn't have 555s then.)
And you had to make protons go round and round in mason jars. ;)
Cheers
Phil Hobbs
"In my day, we defragged hard disks by editing the inodes by hand. With
magnets"
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.nethttp://hobbs-eo.com