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Experimenting means there will be casualties :-)

Started by AK May 4, 2019
This is part of a previous post. Thought I would start a new thread.

"https://blog.prayogindia.in/make-laser-light-security-alarm/"

The directions are poor as hell as is his pictures.

His schematic shows a 6.8 K resistor, but no where is it mentioned in his assembly directions. (I think the author should be drawn and quartered.)

When I hooked it up the first time using a 100 ohm resistor, the bc 547 started smoking.

The alarm and led did light up for a short time. :-)

I hooked it up a different way using the 330 ohm resistor. 

It did not smoke but also did not work.

I am glad I ordered multiple quantities of parts.

I am waiting on parts for another design that uses a 555 timer IC.

"https://makezine.com/projects/laser-tripwire-alarm/"

Andy
On 5/4/2019 2:22 PM, AK wrote:
> This is part of a previous post. Thought I would start a new thread. > > "https://blog.prayogindia.in/make-laser-light-security-alarm/" > > The directions are poor as hell as is his pictures. > > His schematic shows a 6.8 K resistor, but no where is it mentioned in his assembly directions. (I think the author should be drawn and quartered.) > > When I hooked it up the first time using a 100 ohm resistor, the bc 547 started smoking. > > The alarm and led did light up for a short time. :-) > > I hooked it up a different way using the 330 ohm resistor. > > It did not smoke but also did not work. > > I am glad I ordered multiple quantities of parts. > > I am waiting on parts for another design that uses a 555 timer IC. > > "https://makezine.com/projects/laser-tripwire-alarm/" > > Andy >
I don't understand that circuit. He talks about a BC547 and then shows 2N7000 in the schematic. He goes on to do a poor job of showing the connections to the laser. It should be two separate circuits. The first one is your laser, a resistor and the battery. The second would look something like the circuits here.
> https://www.google.com/search?client=firefox-b-1-d&q=LDR+on+base+of+transistor
I suggest you build one of these, the first one should be fine. Shown here,
> https://www.build-electronic-circuits.com/ldr-circuit-diagram/
Replace the LED with your buzzer. Mikek
On Sat, 4 May 2019 12:22:43 -0700 (PDT), AK <scientist77017@gmail.com>
wrote:

>This is part of a previous post. Thought I would start a new thread. > >"https://blog.prayogindia.in/make-laser-light-security-alarm/" > >The directions are poor as hell as is his pictures. > >His schematic shows a 6.8 K resistor, but no where is it mentioned in his assembly directions. (I think the author should be drawn and quartered.) > >When I hooked it up the first time using a 100 ohm resistor, the bc 547 started smoking. > >The alarm and led did light up for a short time. :-) > >I hooked it up a different way using the 330 ohm resistor. > >It did not smoke but also did not work. > >I am glad I ordered multiple quantities of parts. > >I am waiting on parts for another design that uses a 555 timer IC. > >"https://makezine.com/projects/laser-tripwire-alarm/" > >Andy
Can you show a picture of what you've connected? What are you using for a supply voltage? The 2N7000 is a N channel field effect transistor and the BC547 is a bipolar transistor (if I understand it). Those aren't exactly interchangeable parts. Bipolar transistors start conducting with a specific current in the base to emitter junction and a voltage of ~.6 volts. (Point six volts) Mosfets will start conducting at ~2-4 volts with no current flow to speak of. Different animals... Don't get discouraged, it takes a degree of patience and perseverance to learn electronics by building things. You will fail, but if you learn from the failures they aren't really failures. Book-learning can help.
On Friday, May 10, 2019 at 12:35:09 PM UTC-5, default wrote:
> On Sat, 4 May 2019 12:22:43 -0700 (PDT), AK <scientist77017@gmail.com> > wrote: > > >This is part of a previous post. Thought I would start a new thread. > > > >"https://blog.prayogindia.in/make-laser-light-security-alarm/" > > > >The directions are poor as hell as is his pictures. > > > >His schematic shows a 6.8 K resistor, but no where is it mentioned in his assembly directions. (I think the author should be drawn and quartered.) > > > >When I hooked it up the first time using a 100 ohm resistor, the bc 547 started smoking. > > > >The alarm and led did light up for a short time. :-) > > > >I hooked it up a different way using the 330 ohm resistor. > > > >It did not smoke but also did not work. > > > >I am glad I ordered multiple quantities of parts. > > > >I am waiting on parts for another design that uses a 555 timer IC. > > > >"https://makezine.com/projects/laser-tripwire-alarm/" > > > >Andy > > Can you show a picture of what you've connected? > > What are you using for a supply voltage? > > The 2N7000 is a N channel field effect transistor and the BC547 is a > bipolar transistor (if I understand it). Those aren't exactly > interchangeable parts. > > Bipolar transistors start conducting with a specific current in the > base to emitter junction and a voltage of ~.6 volts. (Point six > volts) Mosfets will start conducting at ~2-4 volts with no current > flow to speak of. Different animals... > > Don't get discouraged, it takes a degree of patience and perseverance > to learn electronics by building things. You will fail, but if you > learn from the failures they aren't really failures. Book-learning > can help.
I found a better documented project. https://makezine.com/projects/laser-tripwire-alarm/
Mistakes enlarge your knowledge.
Successes enlarge only your pride.

AK a &eacute;crit le 04/05/2019 &agrave; 21:22&nbsp;:
> This is part of a previous post. Thought I would start a new thread. > > "https://blog.prayogindia.in/make-laser-light-security-alarm/" > > The directions are poor as hell as is his pictures. > > His schematic shows a 6.8 K resistor, but no where is it mentioned in his assembly directions. (I think the author should be drawn and quartered.) > > When I hooked it up the first time using a 100 ohm resistor, the bc 547 started smoking. > > The alarm and led did light up for a short time. :-) > > I hooked it up a different way using the 330 ohm resistor. > > It did not smoke but also did not work. > > I am glad I ordered multiple quantities of parts. > > I am waiting on parts for another design that uses a 555 timer IC. > > "https://makezine.com/projects/laser-tripwire-alarm/" > > Andy
On 5/10/2019 12:52 PM, AK wrote:
> On Friday, May 10, 2019 at 12:35:09 PM UTC-5, default wrote: >> On Sat, 4 May 2019 12:22:43 -0700 (PDT), AK <scientist77017@gmail.com> >> wrote: >> >>> This is part of a previous post. Thought I would start a new thread. >>> >>> "https://blog.prayogindia.in/make-laser-light-security-alarm/" >>> >>> The directions are poor as hell as is his pictures. >>> >>> His schematic shows a 6.8 K resistor, but no where is it mentioned in his assembly directions. (I think the author should be drawn and quartered.) >>> >>> When I hooked it up the first time using a 100 ohm resistor, the bc 547 started smoking. >>> >>> The alarm and led did light up for a short time. :-) >>> >>> I hooked it up a different way using the 330 ohm resistor. >>> >>> It did not smoke but also did not work. >>> >>> I am glad I ordered multiple quantities of parts. >>> >>> I am waiting on parts for another design that uses a 555 timer IC. >>> >>> "https://makezine.com/projects/laser-tripwire-alarm/" >>> >>> Andy >> >> Can you show a picture of what you've connected? >> >> What are you using for a supply voltage? >> >> The 2N7000 is a N channel field effect transistor and the BC547 is a >> bipolar transistor (if I understand it). Those aren't exactly >> interchangeable parts. >> >> Bipolar transistors start conducting with a specific current in the >> base to emitter junction and a voltage of ~.6 volts. (Point six >> volts) Mosfets will start conducting at ~2-4 volts with no current >> flow to speak of. Different animals... >> >> Don't get discouraged, it takes a degree of patience and perseverance >> to learn electronics by building things. You will fail, but if you >> learn from the failures they aren't really failures. Book-learning >> can help. > > I found a better documented project. > > https://makezine.com/projects/laser-tripwire-alarm/ >
But you already have the parts for the circuits I posted. Why not put it together. Mikek
On Friday, May 10, 2019 at 2:52:09 PM UTC-5, amdx wrote:
> On 5/10/2019 12:52 PM, AK wrote: > > On Friday, May 10, 2019 at 12:35:09 PM UTC-5, default wrote: > >> On Sat, 4 May 2019 12:22:43 -0700 (PDT), AK <scientist77017@gmail.com> > >> wrote: > >> > >>> This is part of a previous post. Thought I would start a new thread. > >>> > >>> "https://blog.prayogindia.in/make-laser-light-security-alarm/" > >>> > >>> The directions are poor as hell as is his pictures. > >>> > >>> His schematic shows a 6.8 K resistor, but no where is it mentioned in his assembly directions. (I think the author should be drawn and quartered.) > >>> > >>> When I hooked it up the first time using a 100 ohm resistor, the bc 547 started smoking. > >>> > >>> The alarm and led did light up for a short time. :-) > >>> > >>> I hooked it up a different way using the 330 ohm resistor. > >>> > >>> It did not smoke but also did not work. > >>> > >>> I am glad I ordered multiple quantities of parts. > >>> > >>> I am waiting on parts for another design that uses a 555 timer IC. > >>> > >>> "https://makezine.com/projects/laser-tripwire-alarm/" > >>> > >>> Andy > >> > >> Can you show a picture of what you've connected? > >> > >> What are you using for a supply voltage? > >> > >> The 2N7000 is a N channel field effect transistor and the BC547 is a > >> bipolar transistor (if I understand it). Those aren't exactly > >> interchangeable parts. > >> > >> Bipolar transistors start conducting with a specific current in the > >> base to emitter junction and a voltage of ~.6 volts. (Point six > >> volts) Mosfets will start conducting at ~2-4 volts with no current > >> flow to speak of. Different animals... > >> > >> Don't get discouraged, it takes a degree of patience and perseverance > >> to learn electronics by building things. You will fail, but if you > >> learn from the failures they aren't really failures. Book-learning > >> can help. > > > > I found a better documented project. > > > > https://makezine.com/projects/laser-tripwire-alarm/ > > > But you already have the parts for the circuits I posted. > Why not put it together. > Mikek
I do not have a potentiometer. Andy
On 5/10/2019 3:44 PM, AK wrote:
> On Friday, May 10, 2019 at 2:52:09 PM UTC-5, amdx wrote: >> On 5/10/2019 12:52 PM, AK wrote: >>> On Friday, May 10, 2019 at 12:35:09 PM UTC-5, default wrote: >>>> On Sat, 4 May 2019 12:22:43 -0700 (PDT), AK <scientist77017@gmail.com> >>>> wrote: >>>> >>>>> This is part of a previous post. Thought I would start a new thread. >>>>> >>>>> "https://blog.prayogindia.in/make-laser-light-security-alarm/" >>>>> >>>>> The directions are poor as hell as is his pictures. >>>>> >>>>> His schematic shows a 6.8 K resistor, but no where is it mentioned in his assembly directions. (I think the author should be drawn and quartered.) >>>>> >>>>> When I hooked it up the first time using a 100 ohm resistor, the bc 547 started smoking. >>>>> >>>>> The alarm and led did light up for a short time. :-) >>>>> >>>>> I hooked it up a different way using the 330 ohm resistor. >>>>> >>>>> It did not smoke but also did not work. >>>>> >>>>> I am glad I ordered multiple quantities of parts. >>>>> >>>>> I am waiting on parts for another design that uses a 555 timer IC. >>>>> >>>>> "https://makezine.com/projects/laser-tripwire-alarm/" >>>>> >>>>> Andy >>>> >>>> Can you show a picture of what you've connected? >>>> >>>> What are you using for a supply voltage? >>>> >>>> The 2N7000 is a N channel field effect transistor and the BC547 is a >>>> bipolar transistor (if I understand it). Those aren't exactly >>>> interchangeable parts. >>>> >>>> Bipolar transistors start conducting with a specific current in the >>>> base to emitter junction and a voltage of ~.6 volts. (Point six >>>> volts) Mosfets will start conducting at ~2-4 volts with no current >>>> flow to speak of. Different animals... >>>> >>>> Don't get discouraged, it takes a degree of patience and perseverance >>>> to learn electronics by building things. You will fail, but if you >>>> learn from the failures they aren't really failures. Book-learning >>>> can help. >>> >>> I found a better documented project. >>> >>> https://makezine.com/projects/laser-tripwire-alarm/ >>> >> But you already have the parts for the circuits I posted. >> Why not put it together. >> Mikek > > I do not have a potentiometer. > > Andy >
You can substitute a resistor for the potentiometer. But I note the circuit is probably backwards from what you want. https://www.build-electronic-circuits.com/ldr-circuit-diagram/ This circuit will turn on the buzzer when light hits the LDR. I suspect you want the Buzzer to turn on when the laser beam is broken. So, reverse the positions of potentiometer and the LDR. For clearity we will label the resistor R1. Now, when there is no light on the LDR it has a high resistance, this means there is less voltage drop across R1. Because there is less voltage drop, the voltage on the base of the transistor is high and it conducts causing you buzzer to buzz. With light on the LDR it has a low resistance, lots of current flows through R1 and it has a high voltage drop. So much that the transistor is off and the buzzer does not buzz. Remember this is with the R1 and the potentiometer reversed. If you build it and it doesn't work, give me the base voltage with and without light on the LDR. You might even give me the voltage, dark, with ambient light and with the laser shining on the LDR. Mikek
On Friday, May 10, 2019 at 4:44:15 PM UTC-4, AK wrote:
> On Friday, May 10, 2019 at 2:52:09 PM UTC-5, amdx wrote: > > On 5/10/2019 12:52 PM, AK wrote: > > > On Friday, May 10, 2019 at 12:35:09 PM UTC-5, default wrote: > > >> On Sat, 4 May 2019 12:22:43 -0700 (PDT), AK <scientist77017@gmail.com> > > >> wrote: > > >> > > >>> This is part of a previous post. Thought I would start a new thread. > > >>> > > >>> "https://blog.prayogindia.in/make-laser-light-security-alarm/" > > >>> > > >>> The directions are poor as hell as is his pictures. > > >>> > > >>> His schematic shows a 6.8 K resistor, but no where is it mentioned in his assembly directions. (I think the author should be drawn and quartered.) > > >>> > > >>> When I hooked it up the first time using a 100 ohm resistor, the bc 547 started smoking. > > >>> > > >>> The alarm and led did light up for a short time. :-) > > >>> > > >>> I hooked it up a different way using the 330 ohm resistor. > > >>> > > >>> It did not smoke but also did not work. > > >>> > > >>> I am glad I ordered multiple quantities of parts. > > >>> > > >>> I am waiting on parts for another design that uses a 555 timer IC. > > >>> > > >>> "https://makezine.com/projects/laser-tripwire-alarm/" > > >>> > > >>> Andy > > >> > > >> Can you show a picture of what you've connected? > > >> > > >> What are you using for a supply voltage? > > >> > > >> The 2N7000 is a N channel field effect transistor and the BC547 is a > > >> bipolar transistor (if I understand it). Those aren't exactly > > >> interchangeable parts. > > >> > > >> Bipolar transistors start conducting with a specific current in the > > >> base to emitter junction and a voltage of ~.6 volts. (Point six > > >> volts) Mosfets will start conducting at ~2-4 volts with no current > > >> flow to speak of. Different animals... > > >> > > >> Don't get discouraged, it takes a degree of patience and perseverance > > >> to learn electronics by building things. You will fail, but if you > > >> learn from the failures they aren't really failures. Book-learning > > >> can help. > > > > > > I found a better documented project. > > > > > > https://makezine.com/projects/laser-tripwire-alarm/ > > > > > But you already have the parts for the circuits I posted. > > Why not put it together. > > Mikek > > I do not have a potentiometer. > > Andy
Do you have any electronics books? For a beginner I'm going to suggest "Practical Electronics for Inventors" If you don't buy the latest edition, it's only $5-10. With lotsa good stuff. George H.
Thanks, i will look for it.