Episode: 2645
Title: HPR2645: Blinking LED
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr2645/hpr2645.mp3
Transcribed: 2025-10-19 06:58:40

---

This in HBR episode 2645 entitled, Blinking LED, and in part of the series, Hobby Electronics.
It is hosted by Ken Fallon and in about 23 minutes long, and Karim and Explicit flag.
The summary is, in this live show, Ken sees, if he can follow simple instructions.
Today's show is licensed under a CCMISA license.
This episode of HBR is brought to you by an honest host.com.
Get 15% discount on all shared hosting with the offer code HBR15, that's HBR15.
Better web hosting that's honest and fair at an honesthost.com.
Hi everybody, my name is Ken Fallon, and you're listening to another episode of ACR and
public radio.
Today I'm going to do something a bit different, for a start, my recording setup is in Odessa.
And because I'm in the room here with the fridge, there's a massive buzz on the recording.
But actually I just did a test there, and if I split the audio tracks, the buzzing seems
to be limited to one side only.
I'm very interested to know why that is, if somebody has any ideas you can record a show
as ever.
Okay, I have 19 minutes and 38 seconds to do this show, hopefully it won't take that long.
And I'm doing it live, as we speak.
What is it that you're doing, pray?
Well people will remember back in the New Year's show, I managed to solder a device and
said devices here before me.
It didn't work after the New Year show, but on HPR 2591 International Troubleshooting
in my build, Troubleshoots, a DIY kit for Ken Fallon.
And it's here right now, and it is working.
It is booting up, and it's saying that there are 6.8 volts in this battery, and what I'm
taking, testing is a BJTNPM device, which is really cool, but that's not what I brought
you here for.
As you know, and my build spent quite a considerable amount of money on this device, not only is it
was the shipping more expensive than the device itself, not he bought a camera or a telescope,
a soldering telescope and all sorts and little bits and pieces, so very much appreciate
what he did there.
So I was surprised to find, I was surprised to find, he shipped it back to me, which was
kind of nuts anyway, because it was just so expensive, but he also calibrated the thing,
so I'm really happy to have this device right here on the desk, and it's really nice.
And I'm actually using it, it's very, very handy.
So in, along with this package, was a little piece of form and honor to work, two tiny little
chips, and one look at them had me smiling, because it's NT555P, and the email says,
now figure out how to make those LED blinks, to make LEDs blink with those 555s.
So I'm going to take his LEDs as been one LED, and I went into Duk-Duk-Go, and the first
hit was a flashing LED using 555 timer by TUR-L-E SOTO in technology leds, and it's
CC by NC-SA.
So that is the license that this show will be released under a CC by NC Sherylike.
So if you're not familiar with Creative Commons, HBR all the shows are released on some form
Creative Commons, and you can specify a range of them in this, he is he or she is requesting
attribution, they are requesting attribution would be better, say for all around.
And we can use this for non-commercial purposes, which we're doing, and we can share
a like, so we have to share this show, so I have to release this show under the same license
because I'm using their work.
So that is it, so the first page has a breadboard with a schematic beside it, and for a long
time I didn't know what a breadboard was, to me a breadboard was something that you cut
bread up on, but you get them in all shapes and sizes and they're used for prototyping
electronics.
So they're generally the one I'm going to be using here, quite small number, which is
nice about the size of a postage stamp, if you can remember what those were.
So how they tend to work is on the left hand side and the right hand side, you have two
rows of pins that usually have a positive and negative on them, they don't have to be hooked
up.
If we're looking at this as a rectangular, the long end looking in landscape format.
So all along the top and all along the bottom are two rows of plus and minus.
And then running from top to bottom, top to bottom, there are rows of five pins, so they
have one from the left, level one, the whole way over to the right, level 30.
So the top half, the bottom half is ABCDE, and there's a channel and the top half is FGHIG.
So I'll be using that as a reference.
So everything in pin one is connected together.
So pin one A, one B, one C, one D and one E are connected together.
As our pin one FGHIG and J are connected together, but one A to E are not connected to one
F to J. And that continues the whole way down the breadboard to the point of 30, where
30 A, B, C, and D and E are all basically the same sliver of metal underneath.
And what these things allow you to do is take some basic components, I've got a resistor
and you can pull up them in and it kind of crimps them and holds them.
So that's what a breadboard is, okay?
Moving on.
And on the other side is a schematic diagram.
And it uses like a square rectangle to represent a resistor.
And it uses two black lines together and a crossing to represent a capacitor.
And a resistor, as we've heard already, is a device that will restrict the flow of electricity.
And a capacitor is like a small thing for whole, think of it like a balloon, where it
holds a certain amount, resist a certain amount of current, current, I believe.
All of this is coming from a mechanical engineer who already did this project and it
didn't work just by the way, so don't be getting your hopes up.
From my understanding a capacitor is similar to like a balloon that stores energy, doesn't
allow any energy to flow from one side to the other, but it does store energy.
Now if somebody can give me a better explanation of that, that would be awesome.
Apparently it's like very dust adding more capacitance.
And the last thing is a little LED light emitting diode, okay?
So I've got two resistors that are 1k, 1 kilo ohm, and one that is 470 kilo ohms.
Now, and then we have the 555 timer, which is a tiny little chip of both.
The size of my fingernail and my small hand, which isn't by any means small.
This is a dual inline socket apparently.
This goes to show I pick up stuff from all these YouTube electronic videos I'm watching.
And on most chips there's a little notch to tell you the orientation of it, because you
don't know where the orientation is.
So the notch and this one happens to be at the top.
So that tells me that on the top left, that's pin 1, and then there are four pins going
from pin 1, 2, 3, 4 down the bottom.
And then the bottom right is pin 5, and then working my way up, 678, which is the last
under the top.
So that's it.
Now, as I said, I've done this already.
It didn't work, so the LED came on, but it didn't flash.
So the only thing, so that was different between that and this one, is that I've got a brand
new battery, which is producing 9 volts.
But actually, the component tester is happy to work at 6.7 volts.
So I'm wondering is that the issue here?
So this Instructables article, so Instructables.com, ID, forward slash capital flashing, dash
capital L, capital E, capital D, dash using dash 555, dash capital TIMER.
So Instructables flashing, dash LED using 555 timer.
Which you will, of course, find in the shunnels.
And let me see, there's a video as well, so you need a breadboard, a 9 volt battery, some
battery clips, jumper wires, 555 TIMER, a capacitor, that's 1 micro, 1 micro farad.
Now, how can we test that?
Well, we take our component tester, and we put it in to the component tester, and we
shut the component tester, and we press the magic button.
And it tells me that it is 9.525 nano farads, not micro farads, nano farads.
So I need a 1 micro farad capacitor.
So that, 1 nano farad, is that the same, 1 nano farad?
I'm working on the assumption that that is correct.
It's got one or four ritmos, okay, and then I have two resistors, which I'm now going
to test, press the button, turn it off, which is the battery's weak testing.
And it is 1,000 ohms, which is 1k.
That's good, 1,000 ohms, checking all the components here as I go along, and I'm just
going to replace the battery of that failing battery with a brand new 9 volt battery, which
gives me a total of unknown or damaged.
So I'm going to put the LED in, press the magic button, LED flashes, and it tells me it's
an LED with a forward voltage of 1.94 volts.
So we know that component is working, put another resistor into the tester, pressing the
magic button, and it's telling me 9,98.4 ohms, it's close enough for jazz, I reckon.
And then the final component is a, should be that 470, okay, and it is 456 ohms, not
k.
Oh, hold on, it's 456 ohms, not 456 kilo ohms, folks, do we have our culprit here?
No, I'm going to nip over and get a 456 kilo ohms, but I need a 470 kilo ohms, let me just
test that, right now, 474 kilo ohms, okay, so that could be it, that could be it.
So now what we need to do is basically follow the instructions, which obviously I haven't
done, but I will do it now.
So first thing, there's photographs of everything, I'm actually now going to completely follow
the instructions, I'm putting pin 1 into row 6, 6e.
Now his redboard has labeled the other way around, but I'm going to do it exactly the
same way.
I'm hoping a little, I'm hooking up a red lead to the top positive channel, and I'm putting
that on pin 8, which is row 6 on redboard, and now taking a black lead, and I'm connecting
us to pin 1 of a chip, which is row 6 on the bottom half A to E side, and I'm putting
it into the black channel on the bottom, which isn't connected to a battery as yes, okay,
so that's step 3 done.
So step 4 is to connect a red wire from pin 8 over to pin 8, to pin 4, that's right
there.
Now I've printed off this diagram, and I'm now marking in the connections that pin 4 to
pin is now connected.
I have a connection from pin 1 down to negative, and I've got a connection 8, up to the
buzzer.
There we go, drawn in physically on that circuit diagram.
So that's step 5 complete, step 6 is connecting pin 2 to pin or pin 2 to pin 6, that is correct,
and using a yellow jumper wire, I'll just grab a yellow jumper wire, and use that,
so pin 2, next to pin 4 for 6, so pin 2 is now connected to pin 6, and he has placed
a capacitor onto the leg of pin 2, so pin 2 is connected to pin 6, I draw it in green,
and the capacitor, he's using a electrolytic capacitor, and I'm using a Wondership, using
a electrolytic, might be one microfarad, and I'm a bit concerned about that, I may need
to go look that up, so I'm retesting this capacitor, and I will look that up now, we can
don't want to be a silly bit of, now according to this one microfarad, this thing is actually
0.095 microfarads, so 95 nanofarads is 0.015 microfarads, so that is obviously not correct
as well, there you go, so I will pause this and locate a proper one, that was a bit silly,
but you know this is actually a good thing, because it's made me having to talk out loud,
it's made me have to recheck everything, and yeah, it's silly though, okay, I'll pause
the recording, yeah I should have known, I have it here on my on my board where I keep
all my notes from Dave about weather or weather, and the use of it's in its being, and it says,
yes, we're looking for one microfarad, and one microfarad is equivalent to 0.001001
arads, and that's that, timer's up, or one microfarad is equal to 1000 nanofarads, or 1 million
picofarads, so I will go look at the dinner, and find an appropriate capacitor, I'd be back,
okay, shepherds pie is doing okay, and I got myself a collection of capacitors from dangold,
or no, dulex string, called 132738, some time ago, and they're electrolytic, and it says 50 volt,
one microfarad, and showing the positive and negative legs, because it's an electrolytic
and it is all right, so let us see here, this thing thinks it is, just having to bend the legs,
this region, to all up, need to set another timer, excuse me here, and here are all 15 minutes,
whoop, now it's 15 seconds, 1, 5, 0, 0, okay, on one part, yes, because I haven't done it, press the
magic button, 9.1 volts, testing, and it is a 1070 nanofard, and we know that there are 1000 nanofards
in a microfarad, okay, we'll pause this while we go look for your glasses, okay, glasses are nowhere
to be found, but she has on the plate it, so perhaps they're over there, righty, alrighty, so I'm
looking at a 1000 nanofarads, and we just put that into their 1070 nanofarads, interval for alpha
creditor, creditor is due, and that's 1.0 microfarads, which is close enough for jazz, iraton,
unit, no, and I connect that to the leg of, actually these instructions are excellent,
it gives, he's got numbered instructions in the photos, and then he has the individual component
that he's connected up, so how far he is in total, and the individual component that he's doing,
again I'm presuming it's a he, sorry, this is just, well statistically I'm probably right, but
still, pin 2 to pin to the negative rail, now we've got to be careful here, because the negative
has to go to the negative rail, so that's the short, so the long foot goes to pin 2, the short foot
negative time 100% right about that, yeah, I think so, yeah, so that is step 8 complete, let me
just draw that in here on my dogon, 3 is the whole rail, now the next thing that she, let's say she
connects up is the, is 2 pin 3, it's the 470 kilo ohm, 470 kilo ohm resistor, which we now double
check, and it's 474 kilo ohm, excellent, so I'm connecting that to pin, pin 3, and then out to somewhere
so I can, pin 3 is over there, and resistors, it doesn't matter which way they go around, and the
other leg is in rail 14, so that's pin 3 is in rail 8, and the other leg is in rail 14, so looking
so far, now he has, he we're back to he, has connected, I mean like resistors, the LED, and LEDs are
polarized, yes, so how you can tell which is which is the long leg is the positive one, and if you
look inside you can see like a small bit and an angle, somebody would very long nose, and the
someone with a very long nose bit is the minus, and the plus is short bit, short leg is usually
the minus, and if you look down from the top there's also a little piece cut edge, and then all
three that tells me that this is the minus, of course I can also do this, I can put it into the
tester, press test, and it should also tell me, which is what does it flashes the LED, it's
continuing to flash the LED, turn it on, now we're back, testing, it's testing the LED, and then it
tells me that pin 1 is the positive pin, which is the long leg if we correct, so that's going from
positive to negative, so I'm connecting up the end of that resistor, pin out this is in rail 14,
one is touching the end of that, oh that's wrong, that's wrong, that's wrong, that's wrong, that's wrong,
that is the wrong resistor, three, one pin three is one k resistor, which is one,
see I'm not paying attention guys, I'm not paying attention, yep, have the wrong resistor in
guys, it's going to pin three, over pin four of that, LED, and the LED jumps with one leg to the
end of the one k resistor and the other leg into the rail, so the next part is not shown here
actually in the drawing, so now I'm just going to do, and those are the two resistors, so there's
a resistor going from pin six up to the positive rail, I guess, yeah, pin six up to the
four, and that one is the four seven zero kilohms, four seven zero kilohms, yep, now one is going
from pin six up to zero eight, now that leaves me with one resistor, well actually it doesn't go up to
pin six, pin seven, it needs to, I'm not 100% sure, correct on this, I'm taking that out, and I'm going
to pause for a moment while I check something, okay, I've only got five minutes left until I need to
take the shepherds' pie out, at least, so let me see, I kind of skipped over some stuff here,
the one that I need to connect up, I'm going to do it the same way as they did it, is connecting pin
one four five six to pin seven, with a four k zero resistance, for the third time, we're going to test
this resistor, yep, so what they reckon you do is connect it from rail seven to rail eight,
so I've done that, maybe I just don't have the patience to be trying to get it to be, anyway,
the other one is connecting from rail seven to the positive rail, and that's with my one
resistor, are these even right, 1000 ohms, that's one kilo ohm, correct, okay, and that is showing
it going from rail seven, does it make sense, yes, rail seven up positive, okay, so it looks very
much like step ten, and step eleven is putting in the battery, let's see, of course, what was that,
there's a message from the mother of her friend, and the glasses are not there,
so the mystery of is this going to work or not, right here, connecting up, so I'm going to put in
the connector for the battery, key in, okay, we can get up, we can get up, see what happens,
the LED light comes on my friends, the LED light goes off, we have a blinking circuit, that's
blinking brilliant, that is, I'm fucking shocked by that, absolutely excellent, you probably learned
absolutely zero in this entire episode, other than that you can get an LED to blink with a 555
timer, there is a good book that I'm reading called Make Electronics, and he has a very good
rundown of how a 555 timer works, and how you can get it from stable to a stable and blah blah
modes, so that is something for another time, unfortunately, that is not creative comments, so I
cannot use that, this is working guys, I am chuffed, let's just say the least, anyway, tune in
tomorrow for another exciting episode of hacker public radio, where maybe you will find out
if my shepherd's pie is burnt or not, while we found the glasses, they were in her room,
had her sink, and the shepherd pie needs another five minutes, tune in tomorrow for another
exciting episode of hacker public radio, you've been listening to Hacker Public Radio at Hacker
Public Radio dot org, we are a community podcast network that release the shows every weekday
Monday through Friday, today's show, like all our shows, was contributed by an HBR listener
like yourself, if you ever thought of recording a podcast, then click on our contribute link
to find out how easy it really is, hacker public radio was founded by the digital dog pound
and the infonomican computer club, and it's part of the binary revolution at binrev.com,
if you have comments on today's show, please email the host directly, leave a comment on the website
or record a follow-up episode yourself, unless otherwise status, today's show is released on
creative comments, attribution, share a like, 3.0 license.