My 9v 2 led homemade torch Mk1 & Mk2 £1.50 ($2.75)

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HEY HEY ITS HENDO

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

abvidledUK said:
Go on then, you make one, and post photo's.
... i have fingers like a bunch of bananas and no patience, besides, your making such a good job .....:)

already looking forward to the "next exciting development"
 

TinderBox (UK)

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

I have added a small amount of pen ink from a normal bic type pen to my aradite to blacken it, just mix it in.

it hardened just fine.

regards.

John.
 

abvidledUK

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

TinderBox (UK) said:
I have added a small amount of pen ink from a normal bic type pen to my aradite to blacken it, just mix it in.

it hardened just fine.

regards.

John.

I tried black permanent marker on the outside of one, didn't like it.

I quite like the glow when LEDs on, through the epoxy.

I suppose you could blacken the lower layer of epoxy, to hide switch gubbins.

Leaving the top layer(s) opaque.

Where's your photo !!

I suppose you could add those little sparkly things for card decoration etc. COOL !!
 
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abvidledUK

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

London Lad said:
Hey abvidledUK,

Take no notice, I think its a cool build for £1.25 !

Graham

Switch extra 25p.

I thinks it's gone up now, with having to pay 20p each for battery box for Mk3 version !!..

But then, I've found cheaper epoxy.

I'll amend cost !
 

Oracle

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

abvidledUK said:
INITIAL 80ma

Actual for 16,000 mcd 56ma (that's 28ma each)

Actual for 15,000 mcd 18ma.

Don't forget, after 20 hours on old battery, down to 9ma, as per posts.

It's only what the Paklite basic does.

As for shorting out, not quite, as current is only up to 80ma, and the PP3's don't even get slightly warm.

You said these LEDs are in Series. That's 80mA *EACH*. Go understand Kirchov's Current Law. Connecting a forward bias diode across a power supply is shorting out that power supply. You are getting 80mA because of the internal resistnace of the battery. On paper you'd have infinite current through the LED, but in the real world, there are limits, you can't get infinite current from a 9V battery.

What are you talking about with 16cd = 56mA and 15cd = 18mA?
 
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abvidledUK

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

Oracle said:
You are getting 80mA because of the internal resistnace of the battery. On paper you'd have infinite current through the LED, but in the real world, there are limits, you can't get infinite current from a 9V battery.

What are you talking about with 16cd = 56mA and 15cd = 18mA?

You are fixating on the 80ma INITIAL current too much.

Shorting Carbon Zinc 9v PP3 gives 640ma, go on, try it.

Alkalines probably even more.

Theory is fine, but here in the real world, we know better.

Try reading the post, the different mcd's are for different LEDs, therefore different currents.

I do despair sometimes.

Practical beats theory every time.

May I suggest you actually build your own version, and post results and photo here !

Don't spoil it for everyone else by theorising too much.

So I get 100 hours, or even 10 hours LED life, instead of 100,000. Big deal.

£1.50 !! (or Canadian C$3.20)
 
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Oracle

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

abvidledUK said:
You are fixating on the 80ma INITIAL current too much.

Shorting Carbon Zinc 9v PP3 gives 640ma, go on, try it.

You're dropping the voltage with the diodes while keeping the internal resistance of the battery constant. It's still a short circuit. The only resistive load is the battery itself and the wires.


abvidledUK said:
Theory is fine, but here in the real world, we know better.

You think current adds in a series circuit, you don't know better.
 

London Lad

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

Check the draw with an amp meter in series with the led load, if its not full available battery current then its not a dead short. That's the real world truth!
 

abvidledUK

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INITIAL 80ma is of course through each LED.

Normal 50ma, down to 9ma is also through each LED.

Average, who cares.

LED Life, does it really matter ?

They will spend most of their life consuming 0.04ma, and will last forever (nearly)

£1.50 !!

Mk3 version will address series / parallel configurations, working at 9v and 6v. (as already mentioned), with Ω's chosen from practical testing.

Of course, the cost, apart from time, will be similar.

Now, let's see your photo's, and practical suggestions & potential improvements.
 
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abvidledUK

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

HEY HEY ITS HENDO said:
Hey abvidledUK, lol :) nice thread man, how about switch "on" =2white leds, switch "off"=1flashing type(+resistored)red led ????
i reckon if you sink the flashing red led into the epoxy it may cause a pulsating glow ..wooOooh !!:)

We could even include a small circuit to flash "CPF" in morse.

Or the owners Name & Number !!

or even "I'm over here"
 

London Lad

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

Morse, that's too easy, make it send in binary machine code :lolsign:
 

Oracle

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

London Lad said:
Check the draw with an amp meter in series with the led load, if its not full available battery current then its not a dead short. That's the real world truth!

From Wikipedia:

A short circuit is a low-resistance connection between two nodes of an electrical circuit that are meant to be at different voltages. This results in an excessive electric current limited only by the internal impedance of the current source


In this application, the only thing limiting the current is the internal resistance of the 9V battery and the wires. It is, by definiton, a short circuit.
 

London Lad

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

From London Lads work bench:

A short is a NO resistance connection that draws ALL the available current from the supply (as indicated on my Fluke DMM)

Reality V theory, take your pick
 

Oracle

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

London Lad said:
From London Lads work bench:

A short is a NO resistance connection that draws ALL the available current from the supply (as indicated on my Fluke DMM)

Reality V theory, take your pick

There's no such thing as a no resistance connection. I guess you're the one who has a problem with Reality V Theory if that's your definition.
 

London Lad

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

I'm not really looking for a theoretical row about this. I have been building and repairing electrical items for 30 years as a hobby and as a business. A LED is not a short, 80mA from a PP9 is not a short. An inch long bit of wire is a short. I'm board now.
 

Oracle

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Re: My 9v 2 led homemade torch £1.25 ($2.25) Mk1 & Mk2

London Lad said:
I'm not really looking for a theoretical row about this. I have been building and repairing electrical items for 30 years as a hobby and as a business. A LED is not a short, 80mA from a PP9 is not a short. An inch long bit of wire is a short.

If an LED across 9V is not a short, why don't you connect the same LED across 6 D-Cell NiMH batteries in series. It's the exact same circuit, the only thing changed is the internal resistance of the battery being used.

If I accidently create a solder bridge across the power pins of an MCU, the current draw from the battery will be less, as measured by my Fluke DMM, than if I connect the battery leads with a 1 inch piece of 12 gauge wire. By your definition, the solder bridge is not a short. So what is it?

London Lad said:
I'm board now.

I'm sorry you're feeling flat. I'm a little bored myself.
 

abvidledUK

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Oracle,

Why don't you go and do something CONSTRUCTIVE, literally.

Let's ignore the troll, and hopefully he'll go away.
 
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Oracle

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abvidledUK said:
Oracle,

Why don't you go and do something CONSTRUCTIVE, literally.

Let's ignore the troll, and hopefully he'll go away.

You're right, trying to explain the most basic electronic principles to you is a complete waste of time, you're much to dense.
 

dano

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Obviously, this thread has drifted away from anything cohesive, logical or worthwhile.

Closed.

--dan
 
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