# How-to: turn on a light bulb

All too often, the commentors here on Hackaday display some parsimony in their engineering prowess. If someone uses a Raspberry Pi to blink a few LEDs, someone will invariably chime in that an ARM microcontroller would do just as well. Switching a relay on and off belies the capabilities of a 32-bit Cortex microcontroller when a simpler 8-bit build would certainly suffice. Of course this can always be reduced to a 555 circuit and further still to conditioned pigeons tapping a key in response to either food or opiates. I’d like to take this opportunity to present a tutorial. Not just any tutorial, but the actual foundation of everything we love here at Hackaday: blinky, glowey things.

You can check out the rest of this tutorial after the break.

#### The battery

Put bluntly, every project dealing with electricity needs a power source. Whether through mains power, a solar cell, some sort of strange inductive contraption, or through a chemical reaction, every electronic project needs a power source. I have considered a few different power sources for this project including mains power (far too dangerous to use with a light bulb), a bicycle generator (I’m focusing on strength training this week. Cardio is next week), hamsters and wheels (burning the hamsters as a fuel source and using a heat exchanger to turn a turbine), and magnets (how do they work?). In the end, I settled on using a battery to power the light bulb for this project.

The battery used for this build. It consists of four ‘D’ cells connected together in series via a COMF UM-1×4 battery holder. It provides 6 Volts across its terminals.

The power source for this project is called a battery, as it is made up of a collection of cells. [Benjamin Franklin] came up with this terminology, alluding to artillery formations. Just as more than one cannon is needed to form an artillery battery, more than one cell is needed to form one electronic battery. Yes, this means the AA, AAA, C, and D cells are not batteries per se, but individual cells. They only become batteries when used together. One exception of this is a 9 Volt battery, itself made of eight AAAA (that’s quadruple-A) cells. Seriously. go take a pair of pliers to a 9 Volt battery and see for yourself.

For this project I’ve used ‘D’ cells, as they have a larger capacity than AAA, AA, and C cells. The longer life of D cells is vitally important for this project; I very much expect to have this project sit in the back of my closet or tucked away in some drawer for quite a while until I stumble across it one day and remember the beautiful April morning where I wrote this tutorial fueled by at least two pots of coffee.

Of course just simply putting a battery next to a light bulb won’t do any good. Unfortunately transmission line theory is far too broad a subject to cover in this short tutorial so I’ll just have to cover the basics right now. This battery has two leads coming out of it; a positive and a negative. If we connect the positive wire to the negative wire, electricity will flow through the gap. At higher voltages, a small spark may form. With the voltages we’re working with here, it’s fairly safe, although it is possible to electrocute yourself with even these small voltages. While this may only be possible by stabbing your heart with electrodes and applying power, safety is of utmost concern when playing with electricity.

#### The light bulb

As connecting the positive and negative terminals of a battery together is amazingly stupid, we might as well throw in a light bulb. For this build, I’m using a 6 Volt light bulb that pairs perfectly with our four D cell battery. Just like our battery holder, the socket for the light bulb is attached to a piece of plywood, much more convenient and ergonomic than any flashlight or electric lantern.

You may notice the light bulb is off in the picture below. This is because the light bulb is not screwed down completely into the socket. Yes, unlike LEDs where electrical contacts are soldered on, light bulbs are usually wired into a circuit with a screw-type base. Just as with the lid on a jar of peanut butter, you screw the light bulb into the socket by turning it clockwise. To remove the light bulb from the peanut butter, unscrew it by turning it counter-clockwise.

Before we get into the actual process of turning on a light bulb by screwing it into its base, let’s first consider how a light bulb works. The light bulb was invented by [Thomas Edison] after many, many failed attempts at creating a practical electric light. The light bulb I’m using passes electrical current through a tungsten filament, heating it up and producing light as blackbody radiation. Before discovering tungsten as a perfect filament for an electric light, [Edison] tried hundreds of different materials from carbonized bamboo to the hopes and dreams of a young [Nikola Tesla]. Of course the use of tungsten wasn’t without its downsides – at the time there was no commercial use for tungsten and its extremely high melting point, the highest of any element, made it impractical for use in industry.

[Edison]’s use of tungsten in his successful light bulb guaranteed the continued employment of thousands of tungsten miners in backwoods West Virginia tungsten towns. Life there wasn’t easy, sellin’ your soul to the company store and watchin’ your son grow up to take your job after you’re lost to a tragic cave-in. Of course working conditions improved after the tungsten miner riots of 1824 and the intervention of governor Batman.

In closing, The Professor on Gilligan’s Island was an incompetent fool. As he was clearly not a materials scientist or structural engineer vis-à-vis his inability to fix a hole in a boat, we can only assume he was some sort of physicist or electrical engineer. This is not congruent with The Professor’s actions, though; even a second year EE undergraduate would be able to construct a simple spark gap transmitter using components found in their radio and wiring found aboard the ship.

“Oh, wait.” you say, “broadband transmissions and thus spark gap transmitters are illegal.” Yes, well that’s kind of the point. I guarantee that if The Professor built a spark gap transmitter – and remember, this is the simplest transmitter that can be made out of coconuts and possibly one of Mrs. Howe’s evening gowns – an amateur radio operator would have tracked them down within a few hours. We already know The Professor knew Morse from the season two episode, Ghost a Go-Go, so really there’s nothing stopping the Professor and everyone else getting off the island.

## 92 thoughts on “How-to: turn on a light bulb”

1. XOIIO says:

How to turn on a light:

flick the switch up.

lol but seriously, I hope hackaday isn’t going to do a whole bunch of the basics like this, it would be unbearable.

1. Brian Benchoff says:

Guess how I know you didn’t read the entire post.

1. XOIIO says:

Nah, my attention span is too short lol

2. regrev says:

Or, if you’re in Australia (and i think most of the world) – “flick the switch down.”.

1. Sam says:

Taking into account Australia being upside-down there.

3. lastchancename says:

What’s the MES socket for ?

4. Jarrod says:

Personally I’d love to see more basic stuff like this from time time, it’s great for people just starting out.

1. targetdrone says:

It certainly inspired me. I can’t wait to go build me a hamster fueled generator!

2. Merlin says:

Needs more Arduino.

1. NB says:

i personally think it should have an x84 processor and motherboard with custom gpio card with built in fpga, multiplexing the light at 2000MHZ

1. fractalbrain says:

I couldn’t figure out the directionality of screwing the bulb, so I actully put together a bulb screwing adaptive PID algorithm in my x89. still working on the microwave interface with the bulb though…

1. Sam says:

Glass of milk. Light bulb in glass of milk, put in microwave, ping!

It lights up, at least. Then it probably blows up. Not best way for making hot chocolate.

2. Ayy says:

Needs more Raspberry Pi.

3. regrev says:

Needs less batteries (or cells, whatevs). Far too many batteries for that bulb – i could do it with 1/4 of the batteries in that picture.

3. spam.jam says:

Why throw all that technology at the problem when Flint and Steel would solve your problem at a tenth the cost?

Man people just aren’t hands on with their designs any more. Pre packageed batteries, battery holder, light bulb and socket. I bet you didn’t even make that wire…did you?

1. fractalbrain says:

I had to make my first bulb out of dirt!

4. So where in this post is the light bulb actually turned on?

1. You will have to wait for part 2

1. This post should be called ‘How-to: NOT turn on a light bulb’ then.

It’s sad that on the day I boycott Engadget and other sites for taking childish humor and running with it I still have to be disappointed that Hackaday does not have the common sense to leave these ridiculous “Gotcha!” fluff pieces behind. I bring up Hackaday to Security+ and other classes at my school. Please stop embarrassing yourself and me by doing this. We are above this.

1. wholostwhat says:

You might be above this, the rest of us are more easily amused and also less uptight.

2. defaultex says:

If it gets to ya that much your welcome to come join me for a beer and a laugh. While a lot of the A1 jokes are lame, there are some hilarious ones out there, like what a couple of the game developers have put together.

3. fractalbrain says:

I am certainly not above this!!

4. smee says:

Troll?

Hackaday has absolutely nothing related to Security+. I can’t even remember the last time it had anything relevant to say to an ITSec professional. I don’t see how you could think it is relevant to low level administration in the slightest.

Sure in the way back this was the first site to display hacking OSX via wifi, but that and all other assorted security goodness was deleted many years ago with the big changeover to hardware tinkering.

6. So I was reading a nice tutorial about turning on a light bulb until I got to the last picture. Then completely out of left field, I’m at the conclusion of a treatise on The Professor from Gilligan’s Island.

What’s going on here? How am I ever going to know how to turn on a light bulb??

7. RP says:

“tungsten miner riots of 1824”

8. TacticalNinja says:

This tutorial complete missed the main point — to switch a light bulb on or off. Unless there’s a “Part 2” where different kinds of switches are used, I call the tutorial a failure.

1. Brian Benchoff says:

next year.

1. pall.e says:

I also hope that next year you follow up on the hamster powered stirling engine. Might want to try rabbits instead though because their ability to breed like…..

9. Matt says:

Actually…..even though you couldn’t legally hook one up to a real areal, a post showing how to build (and tune) a basic spark gap transmitter would be pretty cool. There’s *slightly* more to it than just throwing together a bunch or parts on a breadboard.

1. Brian Benchoff says:

I’ve been thinking about my ‘desert island book’. A tutorial to build a spark gap generator would be the book I would want if I’m ever trapped on a deserted island.

Anyone want to fund my kickstarter to write this book?

1. Matt says:

I would be willing to kick some money towards such a project

10. Woodard Evans Jr says:

Woodward and Evans invented and patented the lightbulb.

11. Nice tutorial here. Always wondered how those things worked. Its just missing a schematic.

(maybe an April Fools joke?)

btw, 9V batteries have 6 AAAA cells in them I believe (9v / 1.5v = 6)…

1. chango says:

You fell victim to one of the classic blunders.

1. DainBramage1991 says:

Inconceivable.

2. fractalbrain says:

HAD, you cant joke around by not having schematics! That is not funny at all!

3. rob says:

That’s what I came to say. 6 * 1.5v (AAAA) = 9v, not 8.

12. Brainiac27 says:

Wow this blog always goes overboard. All that carbon dioxide emissions from making lightbulbs and batteries and Gilligan’s Island. Just use a mirror and the sun.

Also if you wanted to use the arduino I made this great library for turning on lightbulbs. Just use Light.on(pin) and Light.off(pin). Check out my lightbulb shield on Tindie.

1. Brian Benchoff says:

Damnit. Now I need to make a light bulb shield for next year.

2. fractalbrain says:

Doesnt it need to be lightbulb.on and lightbulb.off? Just light seems like it would not supply enough current. Anyway, when i use an arduino i append “bulb” to brighten things up.

13. Hirudinea says:

I always wanted a tutorial on a 1 bit computer.

1. I’ve given 1bit computers a bit of thought, and for some purposes they may be a very good idea. When I say 1 bit computers I’m really meaning computers that send the data in series rather than in parallel, eg if data is sent LSB first a serial full adder needs be little more than a 1bit full adder which feeds in the carry result from the previous step. That adder doesn’t worry about bit size at all, it’s as happy on 8 bit as is on 64bit as it would be on 1024bit. – It would just take more steps to complete the sum, but as it’s simpler each step is probably faster, and of course as simpler, more adders can be placed on a given size/tech chip

Timing/synchronisation of data (esp. of different word sizes) might be a bit strange though. Probably need to pipe serial results to some kind of serial registers/buffers to allow it to be synced with other serial data.

14. Rob says:

How to turn-on a lightbulb… uhh, show it pictures of a bare filament?

15. josh says:

Edison was a lying, stealing, cheating, back-stabbing jerk! He never actually invented anything, especially the light bulb. He just stole the plans and passed them off as his own by patenting them before others could.

And, running a light bulb off of mains power would be okay as long as you have a heavy enough resistive load to compensate.

1. inventorm says:

A 60 W light bulb, or any similar size of light bulb, will have enough resistance that putting resistance in series with it will only dim the bulb. They are designed to be inserted directly into a 120 V 60 Hz circuit.

2. Tesla has returned from the grave. Dr Frankenstein resurrected him with .. AC!! ..josh (if that is the name you want to use now, Mr Tesla), welcome back! You are spot on about Edison. Revenge is sweet!

3. Sam says:

Over here they teach us Joseph Swan invented the lightbulb. Hello? Anyone heard of him?

1. Yup. “Thomas Edison, inventor of the lightbulb” is one of many schoolhouse myths perpetuated.

16. I always wondered how that worked. Thanks for the very informative write up!

17. DainBramage1991 says:

This post needs a large industrial knife switch, a Jacob’s ladder, an obscure reference to some deeply nested Linux subroutines, bacon, and 140,000 LEDs soldered together in a perfect geometric shape.

1. That’s an idea… making an elaborate rube-goldberg-like electronic contraption to turn on a bulb…

the jacob’s ladder would obviously need to trigger some sort of mechanical electrostatic switch for example.

1. DainBramage1991 says:

That is a good idea! I’d like to see that.

18. RafMan says:

Cool, but I really want to learn how to condition pigeons to tap a key in response to either food or opiates now…

1. No – use them as a rocket guidance system! Just make sure your rocket motor technology doesn’t get ahead of them…. Wait – use them to guide a quadcopter!

1. Thanks for the link. I first learned about it *way* back in psych 101. I really liked the hack. I think it could be used for quadcopters.

19. chunkeymonkey says:

i got to step 3 but now my hand is stuck in a blender help

1. fractalbrain says:

Quickly pour thermite on the wires to cut them.

20. nukky cisbu says:

Old news. I saw someone switch a light bulb on and off months ago.

1. wholostwhat says:

Yeah, but until now, you had no idea how it was done! It’s not all pixies and magic smoke you know?

21. Rob says:

Q: How many mice does it take to screw in a lightbulb?
A: Two, assuming they’ll fit inside the bulb!

1. But how did they get in there?

2. Q. How many psychiatrists does it take to turn on a light bulb?
A. Only one, but the light bulb really has to want to turn on.

22. Jimmy the Geek says:

Why would the professor leave the island? He had both Ginger and Mary Ann and his only competition was Gilligan.

1. Salman Sheikh says:

true Dat!

23. I thought it was going to be an absurdly complex task needlessly involving a Raspberry Pi and ipv6 and then at the end it would tell you how to sell the Pi on ebay and use the money to buy a switch.

24. biozz says:

im not going to attack HAD on the simplicity … at some point in my life i had the exact same problem im sure of it and had to look up a solution … i used a reed relay controlling a big relay than eventully used a transistor and a relay than a transistor, diode, relay
im sure we all had to google it our selves at some point to figure out how … for me it was flashing lights on a parallel port but todays generation im sure its an arduino or somthing

but like i said SOMEONE has to show it

1. Ricksl says:

This was also a great history lesson, I certainly didn’t know that batman himself intervened in the tungsten miner riots of 1824.

25. Is that “clockwise” viewed from the top, or viewed from the bottom of the bulb? I’m confused.

1. fractalbrain says:

I hope that is explained in part 3!! I was also confused. I’ve tried getting around it by whipping up a quick fuzzy PID logic on my computer to adaptively figure it out direction in real time. Im still working on getting that hooked up to my microwave turn table to screw in/out the light bulb. Trying to get this light bulb figured out before the clock strikes 12.

Great! Thanks a lot HAD, you could have at least put in a warning about the thermite!

2. rue_mohr says:

bulb, I thought you turn the base!?

26. zagrot says:

I thoroughly enjoyed this little death-defying leap of logic:

“Just as with the lid on a jar of peanut butter, you screw the light bulb into the socket by turning it clockwise. To remove the light bulb from the peanut butter, unscrew it by turning it counter-clockwise.”

If it was intentional you are a comedic genius.

27. miq says:

That is one fine bulb you have there.
Is it acceptable to ask for a video-tutorial on how to screw in the bulb? Your article is a bit loose on that.

28. PS Some one probably already said this, but the nine volt is six (6) cells in a case…..

29. jcoutie says:

I didn’t get past the phrase “One exception of this is a 9 Volt battery, itself made of eight AAAA (that’s quadruple-A) cells. Seriously. go take a pair of pliers to a 9 Volt battery and see for yourself.” before realising that I had a dead 9V battery and some pliers sitting right infront of me.

Long story short, I never finished reading the article and now have 6 (not 8!) dead AAAA cells sitting infront of me.

1. fartface says:

Exactly. because it seems that HAD cant do math. Why they ever though there was 8 in there is utterly silly. AAAA cells are 1.5 volts times 6 = 9 volts. But hey let’s not let silly things like math get in the way of electronics.

2. rue_mohr says:

mine is made of rectangular little watch batteries…

3. DainBramage1991 says:

You do realize that this whole post was a farce, right?

30. Oh common, learn how to read, a bulb is something gardeners use’s!

31. The moment I saw this I fully expected the light to be turned on from a switch through an arduino through a raspi through an fpga through a vintage mac modded to be an aquarium.

32. CaptainJistuce says:

Ya know, I’m surprised Tesla’s hopes and dreams weren’t a better light source than tungsten. I’m just sayin’… I think Edison may’ve dropped the ball there.

1. Super Brain AK says:

tesla actually did make his own lightbulbs to light up chicago’s world fair as edison wouldnt let him use them because of the “war of the currents” (tesla saying AC is better than edison’s DC to transmit power long distances), so as the great man that he was he made his own bulbs not using edison’s patents and creating a bulb that was cheaper end easier to produce. though i dont know what kind of filament he used for them but they were designed for AC and were “plug in ones” as not to use edisons “screw in ones”

33. Chris says:

This might work, except Edison proved without a doubt that a carbonized cotton filament would overheat under conditions like these and that is why Tesla should have won. You should go into more detail about the type of filament used by this light bulb, or else some beginners may make the same mistake and become discouraged.

34. Super Brain AK says:

why is the lightbulb screwed into peanut butter?

35. This is THE MOST EMBARRASSING ‘NEWS’ coverage ever shown on Australian TV. Check @ 2:17 for the ‘program to check what number he’s tapping into’

ProTip. Its PING! D:

36. lastchancename says:

From watching the idea suggested in the clip…
Two wire patch cross an existing ADSL line
Sniff traffic for the SIP registration messages
Register your own SIP client with that reg string – or publish it on hacker boards
Deed done.
Not for imbeciles, but appears to be easy enough
But I agree that copper infrastructure is woefully under-secured.

37. randomdude says:

embedding test – sorry had to do it somewhere