Picture of LFTT (LED Flashie Throwie Thingie)
You may already know the LED throwies

The LED Throwies are very cool, however they could be a little more attention getting with just 2 extra components.

This Instructable will show you how to make a flashing LED Throwie.

Step 1: Parts list

Picture of Parts list
To make one LED flashie you'll need:

a 10mm LED (I recommend, that you use a diffuse LED. I live in Denmark and the diffuse LEDs aren't available here, so I just used a waterclear type)

a CR2032 lithium coincell battery.

a Neodymium (NdFeB) disc magnet.

a LM3909 LED Flasher circuit

an Electrolytic capacitor (the bigger the capacitor is, the slower the LED flashes. I figured out, that a 100µF works fine. It will flash the LED at approx. 2.5Hz, while a 220µF will flash it with 1Hz.
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zs1apb6 years ago
Hi there. LM3909 IC's have been obsolete for at least the last 10 years :-(( Anyone know of a cheap source for these? Regards. Tony
yukthi zs1apb4 years ago
yes its true !!!
Artificial Intelligence (author)  zs1apb6 years ago
Are they? I just got them from my local electronics supplier.
Hi there. Only picked up your reply now :-(  Apologies!! Would appreciate you finding out how many LM3909 IC's your local supplier has and at what cost.
These chips have been unobtainable her in South Africa for the last 7 years :-(((  Thanks and regards.
robot13984 years ago
i agree with catman0321
here is a instructable
catman03214 years ago
you can just sand the led down with sandpaper
agis686 years ago
for anyone who needs forgotten LM3909!!! I found in a store here in Athens some boxes containing thousands of this IC, so anyone who wants some of them are available!!! costs 0,80 each
zs1apb agis685 years ago
Hi  there. Are these still available? If so what is the cost and how much to post to South Africa? Thanks and regards. Tony
agis68 zs1apb5 years ago
 I have to check  it first
porryman5 years ago
How much time should the batterie be alive??? I've made the same circuit and the first batterie ruined out in 1 week. I used a 100 µf / 25v capacitor and a ordinary red led diode.
I've read the lm3909 datasheet and with a 1,5 v AA batterie it should be working for at least 6 month.
What could be wrong??

Thank you very much in advance
3unchi5 years ago
Hehehe video sounds like Pentax :D
Artificial Intelligence (author)  3unchi5 years ago
LOL. As a matter of fact, it is actually a Pentax. Do you own one yourself?
Wow, how much radiation does that thing put out?!?!? In the video, it sounds like the geiger counter is going CrAzY!! lol!  Neat idea!
LOL. That's just my old camera trying to focus. It has noisy optics.
more like led sezure throwie just kidding
WHAT PINS!!!!!!!!!
Move your mouse over the pictures to find out.
buteomont6 years ago
You are only 14 years old, and can make better instructables than many adults. Keep it up, you'll make a lot of money one day!
I certainly hope so. Thanks. Actually I'm 15 now.
samphantom7 years ago
Hello there This is interesting but I do not know if you know, but there are in the market built in flashing LED and the cost of those are very cheap, the bad thing is I believe they comes in red and yellow but for the instance u can add this flashing leds in series to another color LED you want. You can find them in Digikey online. But is good though.
Thanks. I know there are some LEDs with a build-in flashing circuit but: 1. The flashing 10mm LEDs aren't available in diffused version 2. With this you can control the flashrate by changing a capacitor 3. The flashing LEDs aren't available where I live and I'm not old enough to buy stuff from the Internet in other countries.
You can diffuse an led by sanding it with sand paper. My mom is from Denmark so I visit there a lot and speak danish fluently.
Coodude266 years ago
Can't you but LEDS with blinking modules built-in?
oh sorry nm
Sandisk1duo6 years ago
blinking LED?
Curious seb6 years ago
What componnent you use to make it and where are you buy it. how long is working with one battery.
The components you'll need are here. I got my parts at a local electronic parts store. I actually haven't tried how long the battery will last, but I guess, it would be around a week.
samphantom7 years ago
Hello my friend. Keep the good track line with your invents, the less I want to do is to take you out of this precious career. Some times is difficult to find components in other areas but still you can order this items sometimes for free in some online sites (e.g. www.texasinstruments.com). But do not worries it will came the day that you can buy your own items. I did not looking for 10mm flashing diffused leds but I'm sure there will be. Anyways thank you for your comments and if there is anything that is on my hands to help you let me know.
Hey, thank you very much.
When I'm 15 years old (in less than one year), I may get my own paypal account, so I can buy stuff from the web =).

And thank you for offering your help.
darkbain7 years ago
Ha, indestructible...how did that happen
darkbain7 years ago
I like this indestructible, it's well illustrated. Blinker circuits (especially for throwies) never get old. Thanks for posting.
dontcha mEAN instructable
assasin0907 years ago
whats a throwie?
Take a look at this
therian7 years ago
using chip for such task is overdue, 2 transistor audio oscillator will do the job and parts can be salvage from anything
I know, that you could do this with a astable multivibrator, but if you did that, the throwie would have to be bigger.
maybe I just too cheep but I love to salvage parts , the feeling of making something from "nothing "
I know what you mean, I salvage parts too. Three times a year, there is a big market nearby me where they sell used and new stuff: clothing, electronics, cups dishes and stuff like that. I often buy some cheap electronics there.
tis is da beeeeeeeeeeeeeeeeeeeeessssssssssst!!!!! :) :) :) :) :) :) ;)
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