Frustration

[AK]

Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.

 

[Rheilly Phoull]

On 14/05/2019 10:22 am, AK wrote:

Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.

Making something is good and relatively easy, when it doesn't work and
you try to find out why is when the real learning begins. Apart from
those who are gifted and can learn with no effort I have no doubt the
people giving you advice here have gone through the same experience.
Just stay calm and double check every thing. Best of luck.

 

[Look165]

Only failures or mistakes  give a lesson !

AK a Êcrit le 14/05/2019 à 04:22 :

Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.

 

[default]

On Mon, 13 May 2019 19:22:56 -0700 (PDT), AK
<scientist77017@gmail.com> wrote:

Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.

If you look at the schematic and have some idea in your mind on how it
is supposed to work... you take your multi-tester and measure a few
things like the junction of the resistor and LDR. If it is greater
than .6 volts the transistor (assuming you used a bipolar junction
transistor) should switch on.

Or are you using the 555 schematic? (The trigger for a 555 has to be
less than 1/3 the supply voltage) 12V supply the trigger has to dip
lower than 4V...

Use logic and think about what is supposed to be going on then use the
meter to see what is really going on.

 

[AK]

On Tuesday, May 14, 2019 at 5:53:47 AM UTC-5, default wrote:

On Mon, 13 May 2019 19:22:56 -0700 (PDT), AK
scientist77017@gmail.com> wrote:

Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.



If you look at the schematic and have some idea in your mind on how it
is supposed to work... you take your multi-tester and measure a few
things like the junction of the resistor and LDR. If it is greater
than .6 volts the transistor (assuming you used a bipolar junction
transistor) should switch on.

Or are you using the 555 schematic? (The trigger for a 555 has to be
less than 1/3 the supply voltage) 12V supply the trigger has to dip
lower than 4V...

Use logic and think about what is supposed to be going on then use the
meter to see what is really going on.

How specifically do I measure the junction of the resistor and the LDR?

I am using the 555 chip.

Andy

 

[AK]

On Tuesday, May 14, 2019 at 6:21:59 AM UTC-5, AK wrote:

On Tuesday, May 14, 2019 at 5:53:47 AM UTC-5, default wrote:
On Mon, 13 May 2019 19:22:56 -0700 (PDT), AK
scientist77017@gmail.com> wrote:

Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.



If you look at the schematic and have some idea in your mind on how it
is supposed to work... you take your multi-tester and measure a few
things like the junction of the resistor and LDR. If it is greater
than .6 volts the transistor (assuming you used a bipolar junction
transistor) should switch on.

Or are you using the 555 schematic? (The trigger for a 555 has to be
less than 1/3 the supply voltage) 12V supply the trigger has to dip
lower than 4V...

Use logic and think about what is supposed to be going on then use the
meter to see what is really going on.

How specifically do I measure the junction of the resistor and the LDR?

I am using the 555 chip.

Andy

I asked how to specifically do this, but did not get a reply.

got a voltmeter to test pin 3&6?
when pin 6 is >6v then pin 3 = 0v
when pin 6 is <6v then pin 3 = 9v

Can someone please show me how?

I assume one probe goes to the pin but where does the other go?

Thanks.

 

[amdx]

On 5/13/2019 9:22 PM, AK wrote:

Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.

Are you know using the 555 circuit.
Mikek

 

[AK]

On Tuesday, May 14, 2019 at 7:29:08 AM UTC-5, amdx wrote:

On 5/13/2019 9:22 PM, AK wrote:
Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.




Are you know using the 555 circuit.
Mikek

I do not understand your question.

Do you know of any circuit that will detect someone crossing a light path?

It does not necessarily have to use a laser.

Andy

 

[George Herold]

On Monday, May 13, 2019 at 10:22:59 PM UTC-4, AK wrote:

Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.

Hmm, Well a common pitfall when starting in electronics is to copy all
of some circuit. Plug it in and find it doesn't work.
A better approach would be to build up one little part of it.. make sure
you know how that little part is supposed to work, and confirm it's
working as expected. (Or not and go figure out why.)
Then add the next little piece.

Do you have an oscilloscope?

 

[default]

On Tue, 14 May 2019 04:27:22 -0700 (PDT), AK
<scientist77017@gmail.com> wrote:

On Tuesday, May 14, 2019 at 6:21:59 AM UTC-5, AK wrote:
On Tuesday, May 14, 2019 at 5:53:47 AM UTC-5, default wrote:
On Mon, 13 May 2019 19:22:56 -0700 (PDT), AK
scientist77017@gmail.com> wrote:

Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.



If you look at the schematic and have some idea in your mind on how it
is supposed to work... you take your multi-tester and measure a few
things like the junction of the resistor and LDR. If it is greater
than .6 volts the transistor (assuming you used a bipolar junction
transistor) should switch on.

Or are you using the 555 schematic? (The trigger for a 555 has to be
less than 1/3 the supply voltage) 12V supply the trigger has to dip
lower than 4V...

Use logic and think about what is supposed to be going on then use the
meter to see what is really going on.

How specifically do I measure the junction of the resistor and the LDR?

I am using the 555 chip.

Andy

I asked how to specifically do this, but did not get a reply.
I'm not glued to the PC this morning...

got a voltmeter to test pin 3&6?
when pin 6 is >6v then pin 3 = 0v
when pin 6 is <6v then pin 3 = 9v

Can someone please show me how?

I assume one probe goes to the pin but where does the other go?

Measurements are assumed to be to ground or voltage minus unless
otherwise stated

I don't have the schematic in front of me but I think pin one is
ground on the 555?


>Thanks.

 

[default]

On Tue, 14 May 2019 07:19:09 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

On Monday, May 13, 2019 at 10:22:59 PM UTC-4, AK wrote:
Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.



Hmm, Well a common pitfall when starting in electronics is to copy all
of some circuit. Plug it in and find it doesn't work.
A better approach would be to build up one little part of it.. make sure
you know how that little part is supposed to work, and confirm it's
working as expected. (Or not and go figure out why.)
Then add the next little piece.

Do you have an oscilloscope?

He is working on a pretty basic circuit. 555 monostable, with a LDR on
the trigger and buzzer on the output.

 

[default]

On Tue, 14 May 2019 04:27:22 -0700 (PDT), AK
<scientist77017@gmail.com> wrote:

On Tuesday, May 14, 2019 at 6:21:59 AM UTC-5, AK wrote:
On Tuesday, May 14, 2019 at 5:53:47 AM UTC-5, default wrote:
On Mon, 13 May 2019 19:22:56 -0700 (PDT), AK
scientist77017@gmail.com> wrote:

Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.



If you look at the schematic and have some idea in your mind on how it
is supposed to work... you take your multi-tester and measure a few
things like the junction of the resistor and LDR. If it is greater
than .6 volts the transistor (assuming you used a bipolar junction
transistor) should switch on.

Or are you using the 555 schematic? (The trigger for a 555 has to be
less than 1/3 the supply voltage) 12V supply the trigger has to dip
lower than 4V...

Use logic and think about what is supposed to be going on then use the
meter to see what is really going on.

How specifically do I measure the junction of the resistor and the LDR?

I am using the 555 chip.

Andy

I asked how to specifically do this, but did not get a reply.

got a voltmeter to test pin 3&6?
when pin 6 is >6v then pin 3 = 0v
when pin 6 is <6v then pin 3 = 9v

Can someone please show me how?

I assume one probe goes to the pin but where does the other go?

Thanks.

OK I found the schematic again... and now I understand he's using the
555 as a simple latch to keep the buzzer on indefinitely

When there's light on the LDR Pin 6 should be low and pin 3 should be
high. (presumably you toggled the toggle switch to set those
conditions)

When light is interrupted Pin 3 goes low and turns on the buzzer until
you flip the toggle switch to turn it off again

Do you have the toggle switch wired as shown? What voltage on pin 6
with light on the LDR, and what voltage on pin 6 with the light
interrupted (blocked)? That voltage has the change significantly
between light and dark.

When the voltage on pin 6 is greater than the voltage on pin 5, pin
3 should be high and the buzzer OFF.

When the voltage on pin 6 dips below 2/3d of your power supply voltage
pin three should go low and stay low, and the buzzer should be ON
until the toggle switch is toggled.

 

[John Larkin]

On Mon, 13 May 2019 19:22:56 -0700 (PDT), AK
<scientist77017@gmail.com> wrote:

Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.

Electronics is frustrating if you put together things that you don't
understand, and they don't work. Why not just buy stuff all done?

If you do want to learn about electronics, start with very simple
circuits that you invent yourself, and do the math, and make it work.

Start with a battery and some resistors a DVM. Do the simple math all
along the way.

After that makes sense, add one big capacitor. Then an LED or two.
Don't move on until you understand it.

An introductory EE course at a community college would be hugely
helpful.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[default]

On Tue, 14 May 2019 07:19:09 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

On Monday, May 13, 2019 at 10:22:59 PM UTC-4, AK wrote:
Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.



Hmm, Well a common pitfall when starting in electronics is to copy all
of some circuit. Plug it in and find it doesn't work.
A better approach would be to build up one little part of it.. make sure
you know how that little part is supposed to work, and confirm it's
working as expected. (Or not and go figure out why.)
Then add the next little piece.

Do you have an oscilloscope?

Here is the schematic
https://cdn.makezine.com/uploads/2013/11/laseralarm.jpg

He's using the 555 as a simple latch to turn on the buzzer until the
toggle switch resets it.

 

[John Larkin]

On Tue, 14 May 2019 07:18:43 -0700 (PDT), AK
<scientist77017@gmail.com> wrote:

On Tuesday, May 14, 2019 at 7:29:08 AM UTC-5, amdx wrote:
On 5/13/2019 9:22 PM, AK wrote:
Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.




Are you know using the 555 circuit.
Mikek

I do not understand your question.

Do you know of any circuit that will detect someone crossing a light path?

It does not necessarily have to use a laser.

Andy

Get a CdS photoresistor and a battery and a few resistors and a
flashlight and a DVM and experiment.

Start by connecting just the photoresistor to the DVM and measure
ohms.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[amdx]

On 5/14/2019 9:18 AM, AK wrote:

On Tuesday, May 14, 2019 at 7:29:08 AM UTC-5, amdx wrote:
On 5/13/2019 9:22 PM, AK wrote:
Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.




Are you know using the 555 circuit.
Mikek

I do not understand your question.

Do you know of any circuit that will detect someone crossing a light path?

It does not necessarily have to use a laser.

Andy

I'm surprised you have already forgot about the first transistor
circuit you posted and then my response with a google search with 25
more transistor circuits.
After I posted you answered the question to someone else, yes you are
using the 555 circuit.
I'm disappointed, you had a chance to learn how to bias a transistor on
or off and then see how the changing resistance of your LDR would cause
the switch on and off.
You should find it interesting to bias a transistor to have the buzzer
quiet, change the value of one resistor and make the buzzer buzz.
Then put the original value back in with the LDR in parallel and see
light make the buzzer go on and off.
You were to quick to abandon the original circuit.

Mikek

 

[AK]

On Tuesday, May 14, 2019 at 9:19:12 AM UTC-5, George Herold wrote:

On Monday, May 13, 2019 at 10:22:59 PM UTC-4, AK wrote:
Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.



Hmm, Well a common pitfall when starting in electronics is to copy all
of some circuit. Plug it in and find it doesn't work.
A better approach would be to build up one little part of it.. make sure
you know how that little part is supposed to work, and confirm it's
working as expected. (Or not and go figure out why.)
Then add the next little piece.

Do you have an oscilloscope?

I have tested the individual parts of circuit that I familiar with. I do not have a scope.

 

[George Herold]

On Tuesday, May 14, 2019 at 11:22:42 AM UTC-4, default wrote:

On Tue, 14 May 2019 07:19:09 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:

On Monday, May 13, 2019 at 10:22:59 PM UTC-4, AK wrote:
Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.



Hmm, Well a common pitfall when starting in electronics is to copy all
of some circuit. Plug it in and find it doesn't work.
A better approach would be to build up one little part of it.. make sure
you know how that little part is supposed to work, and confirm it's
working as expected. (Or not and go figure out why.)
Then add the next little piece.

Do you have an oscilloscope?

Here is the schematic
https://cdn.makezine.com/uploads/2013/11/laseralarm.jpg

He's using the 555 as a simple latch to turn on the buzzer until the
toggle switch resets it.

OK, I haven't used a 555 in decades, and have mostly forgotten how it works.

Maybe he could try a comparator and a S/R flip flop.. Or
just a comparator to LED + resistor.

George H.

 

[default]

On Tue, 14 May 2019 09:34:32 -0700 (PDT), George Herold
<gherold@teachspin.com> wrote:

On Tuesday, May 14, 2019 at 11:22:42 AM UTC-4, default wrote:
On Tue, 14 May 2019 07:19:09 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:

On Monday, May 13, 2019 at 10:22:59 PM UTC-4, AK wrote:
Electronic can be quite frustrating.

I put together a circuit for a laser alarm.

It does not work.

There is no way to tell if a design will be successful even if you follow the authors exact directions.

I will keep plugging away and reading Practical Electronics for Inventors.



Hmm, Well a common pitfall when starting in electronics is to copy all
of some circuit. Plug it in and find it doesn't work.
A better approach would be to build up one little part of it.. make sure
you know how that little part is supposed to work, and confirm it's
working as expected. (Or not and go figure out why.)
Then add the next little piece.

Do you have an oscilloscope?

Here is the schematic
https://cdn.makezine.com/uploads/2013/11/laseralarm.jpg

He's using the 555 as a simple latch to turn on the buzzer until the
toggle switch resets it.

OK, I haven't used a 555 in decades, and have mostly forgotten how it works.

Maybe he could try a comparator and a S/R flip flop.. Or
just a comparator to LED + resistor.

George H.

I had need of a break-beam photo detector in the 60's to keep my
motorcycle from being stolen. I used a potentiometer, photocell, and
SCR for the latch to keep a doorbell ringing. (the inductive kick and
contacts opening meant it wouldn't latch until I added an electrolytic
cap across the bell) We didn't have integrated circuits.

 

[Cursitor Doom]

On Tue, 14 May 2019 08:20:22 -0700, John Larkin wrote:

Electronics is frustrating if you put together things that you don't
understand, and they don't work. Why not just buy stuff all done?

If you do want to learn about electronics, start with very simple
circuits that you invent yourself, and do the math, and make it work.

Start with a battery and some resistors a DVM. Do the simple math all
along the way.

After that makes sense, add one big capacitor. Then an LED or two. Don't
move on until you understand it.

An introductory EE course at a community college would be hugely
helpful.

The OP can be comforted by the fact that expecting a circuit to work
first time after building it is unduly optimistic. Even simple circuits
it's easy to overlook something, no matter how experienced you become. IME
(very considerable over 50+ years) the majority of circuits do NOT work
first time and so need time spend re-checking everything. You just get
quicker and quicker at the checking and testing procedures!





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