Programmable LED

Inspired by various LED Throwies, blinking LEDs and similar instructables I wanted to do my version of an LED controlled by a microcontroller.

The idea is to make the LED blinking sequence reprogrammable. This reprogramming can be done with light and shadow, e.g. you could use your flashlight.

This is my first instructable, any comments or corrections are welcome.

Update 12/08/2008: There is now a kit available at the Tinker Store.

Here is a video of reprogramming it. Sorry for the quality.

Step 1: How it works

An LED is used as output. As input I used an LDR, a light dependent resistor. This LDR changes its resistor as it receives more or less light. The resistor is then used as analog input to the microprocessors ADC (analog digital converter).

The controller has two modes of operation, one for recording a sequence, the other for playing back the recorded sequence.

Once the controller notices two changes of brightness within half of a second, (dark, bright, dark or the other way round), it switches to recording mode. In recodring mode the input of the LDR is measured multiple times a second and stored on the chip. If the memory is exhausted, the controller switches back to playback mode and starts to play the recorded sequence.

As the memory of this tiny controller is very limited, 64 bytes (yes, bytes!), the controller is able to record 400 bits. That is space enough for 10 seconds with 40 samples per second.

Comments

[Ploopy]

Cool

What happens when the memory runs out?

[techno guy]

can this be done on an arduino? if so, what's the code?

[diy_bloke]

Yes it can, use the main C source code. Load that into yr arduino and compile. Often that will give you some error messages coz c specific code might be used but in thi scase it compiles without problems so I guess it would work.

[rabril]

Is there anyway you could program an L.E.D. to stay on for one hour, turn off and turn back on after 11 hours?

[ovan der beek]

use an arduino

[Orngrimm]

Haha! Cool idea! I like it.
Simple but nice.

Keep up the good 'ibles. :)

Also i think i may copy your method of "Ubersimple-3V-supply". Simply mindblowing ;)

[caarntedd]

Love how this is put together, sort of looks like a primitive robot. Can robots be primitive? 5 stars.

[thelastonekills]

that is soo cool. and a nice twist on a Throwie and aslo something good to improve skills.
5/5

[robot1398]

can i do this project with a pic by any chance and if yes schematic please

[elecsl]

Greate project. Thanks for sharing. lk-tech

[brooklynlord]

I don't really understand the C file and hex file....

Which am i supposed to program?
What is the other one for?

[raykholo]

 if you want to use this for its intended purposes, upload the HEX file to the chip using an avr programmer.   (AVR Studio works to upload the hex).  If you want to change the code, then you would go to the "main.c" file...
Good luck!  and please reply back with any more questions.

[raykholo]

 I am trying to read a pot using ADC on my attiny25v chip (same family as yours).  Is there anything I should know in regard to using your code as an example for my program in AVR Studio?  (this is for a Servo Tester - 10k pot to servo position, and also a button to center it).  
Thanks

[cefn]

Those commenting on the project might be interested by this alternative approach...
http://enigmaker.org/post_project4_reveal.html

[knektek]

instead of the low current led, perhaps a transistor would be handy, if you wanted to do it the other way round, use a mosfet.

[Junkyardmaster14]

how can you connect the IC to the computer? what is the connector, adapter or something to connect it and program to a computer?

[godofal]

with a programmer of course :D
for this type (attiny13 is an AVR chip) u can use the ghetto programmer described by the real elliot (just search it here) that works with the serial (printer) port of ur PC
or make/buy a USBtiny from www.ladyada.net that's a bit more expensive, but it works with ur USB port and doesnt need a power source.

hope it helped, if u have questions about the ghetto programmer, just PM me.

[seandogue]

(removed by author or community request)

[godofal]

or, switch it on and power it from the battery, then u wouldnt need that jack!

[zebratangozebra]

I love this !
Great ideas !
The freestyle assembly and minimal parts make it a less is more thing.
Thinking it might be interesting to maybe use a few more parts to make it look like a man or robot or something.

[penester]

Hi Alex, im a c c++ c# programmer but am very interested in programing circuits as a hobby. 
Your tutorial is very simple im sure, but is there a chance you could point me to a ultra nubby circuit programing tutorial?

Any help would be good as ive never tackled this before.

[alex_weber]

Ehm, are you the same guy as zezba9000? Or have you just copy'n'pasted the question?
I answered exactly this question (scroll down a bit to see it).

[penester]

Thank you so much my dear / alex_weber .
and i AM  HOPE TO BE FUN  WITH GOOD HEALTH. 

[DjFluorescent]

 would the chip used here, to program the led, work with sound instead of an LED? i do alot of DIY synth projects and circuit bends. this would be a great addition if compatable.......    :)

[alex_weber]

In theory, yes. If you succeed, please let me know.

[zezba9000]

 Hi Alex, im a c c++ c# programmer but am very interested in programing circuits as a hobby. 
Your tutorial is very simple im sure, but is there a chance you could point me to a ultra nubby circuit programing tutorial?

Any help would be good as ive never tackled this before.

[alex_weber]

Hi,
take a look at http://www.avrfreaks.net
They have nice tutorials.
Or, another good starting point, especially for software developers, is the Arduino project. Really easy to get started.
http://arduino.cc

[trouble01]

greeeaat!!!

[aliasjanedoe]

Can this only blink on and off, or can it fade also?  Such as if you program it using a light with a dimmer switch.  And does anywhere sell just the chip (not a full kit) with the program already on it?  When you remove the LDR, does the chip remember the last sequence entered from then on, even if the battery goes dead and has to be replaced?

[alex_weber]

Yes, you could make it fading. For that you should google for PWM (pulse width modulation).

The recorded sequence is stored in RAM, so it would be lost if the battery goes dead. But you could store the sequence in EEPROM.

[brunoip]

What is the difference between an ATtiny13V and an ATtiny13A ? Bruno

[alex_weber]

The ATtiny13A is a replacement for the now "old" ATtiny13V and should be pin-compatible.

[Jodex]

Looks like really cool!

[ktalex]

is their such thing as a cell that powers when there is no light then when there is light?

[bambangpe]

from electric become art so called electricart

[shandoo]

Very nice one! Funky gadget!

[tintenfisch]

Hi, can you recommend a store where I can get the Atmel ATtiny13v, the other components and the tools required? (breadboard and AVR programmer) Cheers, Jonathan

[Rportal]

sparkfun.com wide variety and stock. reasonable prices.

[alex_weber]

Hi tintenfish,
looking at your nick, I assume you are living in a german speaking country?
For cheap ATtiny, have a look at: http://www.csd-electronics.de/de/index.htm
They have breadboards and other components as well. For a programmer, check out the USBtinyISP from adafruits.
Cheers,
Alex

[tintenfisch]

Hi, thanks for your reply :) You are almost right.. it is a German word and I'm from Sweden, but I live in New York City right now.. Do you know any stores in the states? Also, should I get SOIC or PDIP? Is there any difference between them? Cheers, J

[hoonflap]

sparkfun carries most of the atmel chips, and this instructable is a great intro to avr, with instructions on how to build a cheap programming cradle.

[alex_weber]

Hi Jonathan, I'm sorry, I don't know any stores in the US. But you should look for the PDIP package, that's the one I used. The other one is an SMT package and very tiny. Cheers, Alex

[Deyus]

You Can get a few different types of breadboards on this site how ever I don't know where to get the AVR programmer

http://www.abra-electronics.com/products/catalog/Boards-orderby0-p-1-c-7.html

[Redgerr]

looks cool at the end and functional! very nice O-o im sure you could sell the programed ATtiny chips or sold everything in a pack to build yourself O_o just a thought ;)

[alex_weber]

If you look closely above, there is a link to the Tinker Store, where I sell kits of the Programmable LED ;)

[jpr55]

Hi Alex, Great project. I want to build a circuit for my son who is learning mores code. I think I will have no problem building the device but not sure how to program the ATtiny. How do you download the program to the ATtiny? Where do I get the Mymultipro device? I have a computer and I assume I build the program in sw named above and hit download to the Mymultipro and the rest is history. I also saw the video and it shows using light to train the circuit. Which method do you use. If you have to train the ATtiny with light as in the video then how do you protect it from outside influences? Thanks much, JPR55

[alex_weber]

Hi jpr55,

I am using now the USBtinyISP programmer from adafruit. Very handy.
http://www.ladyada.net/make/usbtinyisp/
You will need a breadboard to setup an programming environment, as you can not program the Programmable LED in circuit. You first have to program the controller and then solder everything together.
Here is another good starting point to learn how to program microcontrollers:
http://www.instructables.com/id/Ghetto-Programming%3a-Getting-started-with-AVR-micro/

The circuit enters the recording mode by a light pulse, "dark - bright - dark", or the other way round, "bright - dark -bright". That way it should not take up outside influences. Although, I saw it on time happen as it got slowly darker, the ambient light triggered the switching.

Cheers,
Alex

[FagnerFS]

it's a very good project! Congratulations! i can't build it, because i have anything. i'll build it later :(

[Redgerr]

"i can't build it, because i have anything" ?

[nluken]

Awesome project! such a beautiful little sculpture at the end. As a newbie, I'd like to try to try adapting the software to use an arduino! Question: shouldn't the mA number in the above formulas be .020 (20 milliamps) vs. the .002 shown? I was under the impression that leds were generally 20 mA or so.

[mikemich]

yes you are correct

[alex_weber]

Hi nluken, you are right, standard LEDs take 20 mA. I used low current LEDs, these take only 2 mA. That helps to a more long-living project. As you know, we all have to save energy. ;) Regards, Alex

[dark sponge]

Would an Attiny13a-pu work? It's what I have lying around and I already downloaded the code onto it. I have yet to build the circuit because I lack the LDR...

[alex_weber]

Yes, that one should work.

[dark sponge]

Also, I know this would make it not as cool but could I replace the LDR with a push-button and still have it function normally? By looking at the schematic I think It should.

[alex_weber]

Sure, it would work. Even better would be to connect the push button with a pull-up resistor.

[dark sponge]

So does the LDR have have a lower resistance in brighter light?

[alex_weber]

Yes, it does.

[dark sponge]

Ok, thanks.

[sean22]

Could you use a comparator and get the same result

[amando96]

you can detect when the light is there or not...
http://home.cogeco.ca/~rpaisley4/PhotoDetectors.html

[alex_weber]

No, you need something to sample the input (light sequences), store it and then play it back. That's what the microcontroller does.

[Mascimo]

If you make a lot of those, would they interact?

[raykholo]

i dropped an idea just now (see pic question above) that pic microcontrollers can communicate w/ each other of ir... so u could program 1 the original way, then have it send a sequence and start command to the next one when done, and so on. by transmitting the sequence each time, it is possible to change it... so figure it out. B-)

[alex_weber]

Hi Mascimo,
yes, they would. Take a look at my other instructable for an example.
http://www.instructables.com/id/Synchronizing-Fireflies/
Cheers,
Alex

[imarzouka]

Anyone did it with a PIC microcontroller? I don't have an Amtel programmer so I want to use my PICKit 2 programmer.

[raykholo]

pic microcontrollers can communicate via ir so u can have a second unit which will program this over ir... u will have to replace the photo sensor with an ir sensor and design a second module....

[alex_weber]

Yes, Dr. Skippy did it.
http://drskippy.net/blog/2007/04/picbased_programmable_led.html

[imarzouka]

Great!! Thanks :)

[marc00703]

Hi I'm 14 and i was just wondering what could i use if i don't have a Atmel ATtiny13v... coz i can't find it in my father's office...Thanks

[marc00703]

I found this: a Microchip 12F675

[alex_weber]

If you know how to program that one, it'll be fine.

[marc00703]

No I don't know how to program anything lol

[asylum1]

this is the greatest thing ever. i am just wondering where u uploaded you video thats right there get back at me.

[guitarist24000]

I have never programmed a micro controller before, but would the following parts work for this instructable?
http://www.sparkfun.com/commerce/product_info.php?products_id=31

http://cgi.ebay.com/ATMEL-ATTINY13V-10PU-IC-MCU-AVR-1K-FLASH-10MHZ-8DIP_W0QQitemZ380075597783QQcmdZViewItem

http://cgi.ebay.com/USBasp-ATMEL-AVR-ATMEGA-ISP-Programmer-USB-AVRDUDE-5-2_W0QQitemZ230302731460Q

[alex_weber]

The first is a prototyping board, which you don't need. The others are fine.

[guitarist24000]

So what can I plug the chip into to program it as well as the usb wire Iknow it would go from the computer, to usb cord, to BLANK, to microcontroller

[alex_weber]

There are two types of programmers. The one that I used for this setup (where you plug in your controller) and ISP (in system programmer). ISPs don't have sockets to plug your controller into. They have connectors to plug into your circuit, to program this chip in the system. ISPs are cheaper, but you have to setup your system to be able to program the controller.
Take a look at http://www.instructables.com/id/Ghetto-Development-Environment/
It's a good tutorial to get started. It uses another programmer, the USBtinyISP which I can recommend.

[zklapow]

Yes but even if you do use an ISP it doesn't mean you have to make your whole system, you can make a target board. you can build something quite easily like what is shown http://www.evilmadscientist.com/article.php/avrtargetboards

[codongolev]

you could make a throwie that you...erm.... don't really want to throw.

[Kryptonite]

That would just make it an LED, not an LED throwie. But it's not a plain LED, it flashes... What do you call it then?

[Tommyhzy]

A Flashie!

[codongolev]

flashies look trashies. just kidding, I liked the pun.

[Kryptonite]

Or, as I like to call it, a Flasher!

[Geosync]

Just catching up here...call it a Flashie Throwie...please. :-)

[Kryptonite]

Yeah we're just making puns out of codongolev's comment above. :D

[james.mcglashan]

cant u just put that on th curcit board and have it smaller and all in 1 little spot nice and easy thats what i did

[james.mcglashan]

i mean thats what ill do not did itll fit and work and with much smaller leeds

[alex_weber]

Yes, you could make still smaller by using SMD components.

[Kryptonite]

Very good for complete begginers, nice instructions & everything! We actually made one of these in Electronics for school, but no micro chip, a lot more components, & it used capacitors & a LDR.

[ismaelplague]

nice one

[Eeeeeeeeeekz]

wow very smooth

[ninilium]

Great Instructable! It was a very good read and the "hacked throwie" approach is excellent. Your minimalist design is an art form. There is a name for this type of construction technique, and it escapes me as most words do when there is a need for them. Simple, Beautiful work!

[alex_weber]

Thanks a lot. Do you mean "free form"?

[caterr]

If my knowledge in electronics is correct you should be able to implement any kind of input device. Use your imagination... a microphone or a push button would work. Also any type of contact switch would work to maybe detect and replay things like vibrations. This project is not limited to just an LDR input. Have fun :)

[javier7high]

exactly, and thanks for waking the idea up!

[dikos]

Spider Programmable Led

http:www.grobot.gr

[dikos]

(removed by author or community request)

[dikos]

(removed by author or community request)

[digitalrox]

Hiii, very nice project i liked a lot, so i'm trying to do it too. But i have a big question. Can i use a ATtiny2313 - 20 Pin 20MHz 2K instead of Atmel ATtiny13v? Because i could use the programmer that i saw somewhere in this page, and because in my country those parts are very difficult to find. Thanks a lot, and sorry for being such a "newbie" :)

[alex_weber]

Hi digitalrox, the ATtiny2313 has a lot more pin than needed, but lacks an ADC (Analog Digital Converter). Without it, it is hard to measure the light. You can try to use a digital input pin and see at what level it reads a high level. Maybe you have to adjust the resistor values for that. If you look for other controllers, check it they have ADC support. And eight pins are enough for this circuit. HTH, cheers, Alex

[digitalrox]

What about a ATMega168 or a ATMega8? I can't find microcrontrollers with 8 pins. Actually the ATMega8 is the one with less pins that i have found that has A/D. Thanks for replying :).

[alex_weber]

An ATmega8 would work. But you have to adapt the source code, as some registers are named differently.

[Pumpkin$]

nice man! I was listening to canned heat when I saw this... sweet! 5+ feel free to enquire about our group THE ALLIANCE

[imarzouka]

Great project!! You can also use this calculator for the resistor values

http://ledcalculator.net

[technodude92]

can you pre-program a sequence for the LED to flash? maybe a message in Morse code?

[twenglish1]

yah i have done it before and if you need help i will help you, i made one to blink S.O.S in Morse code

[alex_weber]

Sure, you could. That would be easy to add.

[craigl]

Neat project, Alex. I didn't have any low power leds around, but I did have an RGB 4-lead led and noticed that PB0 and PB1 were left free on the project, allowing me to hook up red, green, and blue (green on PB0, blue on PB1, and red on PB2). Doing this also means that you can flash green to indicate programming start, blue to echo during programming and playback, and flashing red to indicate the end of programming. This eliminated some of the confusion over when programming was actually happening. Since this RGB led can also display white (when all three colors are lit), it opens up some interesting possibilities - you could add colors up to white to reflect a continuous lit period, then turn them off to reflect continuous dark.

I got my ATtiny13's, button cells and RGB leds from Sparkfun (recommended!). They didn't have the ldr you used but they did have a neat little ambient light detector that easily takes its place (had to adjust the THRESHOLD a bit though).

A fun project. I like seeing how far I can stretch that 1K of program space.

This project inspired me to haul out the stk500 I got a couple of years back and update my AVR tools on the Mac. FYI for those that want to do AVR programming on the Mac, I can strongly recommend a binary pre-built package that lets you work in XCode, and you can download it for free at

http://www.obdev.at/products/avrmacpack/index.html

I also recommend downloading the very nice AVRFuses freeware for the Mac , available at

http://www.vonnieda.org/software/avrfuses

It makes selecting fuses a snap and can upload to many types of AVR programmers via common USB to serial dongles.

Thanks again for a fun project, Alex!

[alex_weber]

Craigl, thanks. Do you have any pictures to share? I would like to add them to my gallery. Cheers, Alex

[neardood]

dood, add a case or some form of PCB

[samirsky]

Alex, I noticed on "playback" that the LED would do a series of flashes at the end of the pattern. It looks very similar to the signal that indicates the end of programming. Perhaps this is by design, but I wanted a repeating pattern (like SOS) without the flashes between repeats of the pattern. I can not figure out why it does this on playback. I solved the problem by changing the MAX bits recorded 3 bytes less to 376. Newbie Questions: Do you have any idea of the cause of the flashing on playback? Any idea why using 47 bytes of RAM instead of 50 fixes the problem? Similarly, why did you choose to use 400 (50 bytes) rather than using the full 64 bytes available in RAM?

[alex_weber]

Hi Sam, the original source does not have a flashing at the end of the playback cycle. Maybe the program errors and the controller resets. The flashing could be the flashing at the boot up cycle. Why not using 64 bytes? Every other variable needs memory as well. On top comes memory for the stack (used to store parameters of function calls). That means in the original code we have 3*uint8_t and 3*uint16_t are 9 bytes + 50 bytes for the playback storage. That's already 59 of 64 bytes. Maybe you have added new variables? HTH Cheers, Alex

[samirsky]

Ahh...it must be from adding variables. I added the THRESHOLD calculation suggested by zzag (9/3/07), which added 1, maybe 2 variables of type int. Is type int an int8 or int16? In that case, it is amazing that it still worked. It seems like it is attempting to overwrite one of the variables, or at least trying to use more memory than is available.

[alex_weber]

Always use uint8_t (0-255) or uint16_t (0-65535) or the signed ints (int8, int16). The size of int, long, etc. depends on the architecture you are building for (8-bit, 16-bit, 32-bit, etc). So, check if you are using values > 255. Then use uint16_t, else uin8_t. HTH, cheers, Alex

[samirsky]

Alex, This was a fun project. I was initially attracted by your parts-direct-connect version. However, the Lego version by Tristantr inspired my final design. I plug the neg battery lead into the 14-pin socket to turn it on. I had a problem with the threshold even after adding the lines suggested by zzag. It was fixed once I moved the THRESHOLD calculation before the 'while(1)' loop, so that it was not recalculated every pass (oops!). Lots of fun. Thanks. I will be looking for more projects like this one. Sam

[alex_weber]

Hi Sam, that's a nice one! Thanks for sharing the picture ;) Cheers, Alex

[zzag]

excellent alex!!

as maybe another suggested adder... i couldn't find an equivalent LDR, so had to modify the 'threshold' to get it to read. so i thinks to myself: why not automatically set this threshold. i added an autocalibration routine at power up to read the ambient light and set the threshold number 50 counts away so the LED lights in ambient.

somewhere before "if (programming)" insert:
int THRESHOLD;
THRESHOLD = (int)get_adc(CHANNEL)+50;

(delete the "define# THRESHOLD 800" line)

[alex_weber]

zzag, you are right. That's a better adaption to the environment. Any photos to share? I could host a gallery :)

[zzag]

. ... i finally found the time to finish mine. thanks for the inspiration! ... .

[lifelong-newbie]

Have to commend that work, its an excellent incarnation of this great and original idea. Good wire work, especially to get those pretty symmetrical and make it look a weird combo of la-de-da and steam-punk.

[mortso]

Yah! Needs to be in MOMA !

[justy]

Beautiful wire work!

[Robotrix]

The carriage you built for this is amazing. I never would have guessed that you could make an IC and some components look steampunk, but here you have it. Nice work!

[alex_weber]

Wow! That one looks fantastic! Thanks for posting the photos. Keep up the good work. Cheers, Alex

[sockeye101]

a note...
reading the data sheet, i found that operating the circuit below 1.9v can cause the memory to not be saved, so the 3v battery is fine.
heres the link: http://www.atmel.com/dyn/resources/prod_documents/2535S.pdf

[Robotrix]

I love how you designed the look of this. It's self contained and sculptural, and it has a lot more presence than it would if you had just piled the components together. Really really neat!

[mkamchin]

could you ad 7 more LEDs to the circuit...how???

[alex_weber]

You can add more LEDs if you use a transistor to drive more current. They will ligth up as the single one does.

[CCH3ST3R]

could you replace the light sensor with a push button please respond

[alex_weber]

Sure, that's easy as well. But also a bit lame, don't you think? ;-)

[chaydgb]

Cool project! One little tweak that would save the cost of an LDR and support circuitry would be to use the LED as a sensor as well as an emitter, meaning you'd only need an led and the micro. You could cycle the led on and off, and sample light levels during the off periods. Would mean more coding, but it would be cheaper in the long run, especially if you're planning on making a large array of devices.

See this link for more info on LEDs as sensors: http://projects.dimension-x.net/technology-and-projects/ledsensors

[clarsen]

What's the battery life on this, say assuming 1/2 second on, 1.5 seconds off? Planning for Christmas ornaments for 2008...

[alex_weber]

Hi clarsen, the battery has 220mAh and the LED needs about 2mA. Assuming 3mA for the whole circuit, it will live for 73.333 hours or 3.055 days. If the LED is lit only a quarter of the time, then it should last at least 12 days. If you are planning to have a fixed sequence of lightning, then there are easier circuits to achieve this, e.g. with a "555" timer chip or "astable multivibrator". Cheers, Alex

[Deyus]

Awesome Idea, I am just wondering how I can get a hold of the AVR Programmer board and how much it costs? I found how to make one my self but it is only for the 8pin ATtiny AVR microcontollers

[hoonflap]

the avr family are programmed in similar fashion. you need MOSI, MISO, SCK, RESET, and GND to program your chip using this cradle. these can all be found on your avr chip's datasheet. just make the cradle on a breadboard and hook the pins up according to the pin map.

[alex_weber]

Hi Deyus,
I can recommend this USBTinyISP from adafruits:
http://www.adafruit.com/index.php?main_page=product_info&cPath=16&products_id=46
It's fast, very well documented and costs $22.
Cheers,
Alex

[alex_weber]

Hi,

I am now hosting a gallery of all Programmable LEDs at http://tinkerlog.com/2007/11/28/programmable-led-gallery/
If someone else has a version to contribute, please let me know.

Cheers,
Alex

[tristanr]

Well, here's my version: wearable computing for a Lego minifig. The only changes I made from the original instructions were: hardware: - roughened LED surface with fine sandpaper to make it more visible - added a switch (behind his feet) - used wires from a 20-core data cable (pre-twisted to give the candy-stripes) - stuck lego to battery with hot-melt glue software: -added the auto-detect threshold change (zzag comment 2007-09-03) but using -50 instead of +50 to detect dimming - deliberately set the clock speed incorrectly to 4000000 in order to increase the record time to around 30s (alex_weber comment 2007-11-13) Thanks for a great instructable, Alex!

[alex_weber]

Tristanr, man, these are really cool! Your idea and implementation is great. I especially like the wires and the two devices in its hands. Cheers, Alex

[tristanr]

Thanks for a great instructable! I've sucessfully prototyped one of these, but I am finding that a) the 'record time' is way higher - over a minute (which, divided by 400 points means approx 6 samples/sec) and b) I can't get it to enter programming mode by alternating dark/bright (although it works fine if I switch it off and on) Does anyone know what's going on? Have I reset the clock speed or something (I was using a boilerplate Makefile from WinAVR to do the compile and to run avrdude)

[alex_weber]

The ATtiny should run with 1MHz without a crystal or resonator. Be sure to have a defined symbol in your makefile, like "-DF_CPU=1000000".
"-D" stands for the define symbol, "F_CPU" is the symbol that defines the speed of the ATtiny. If it is set to a wrong value, your ATtiny will wait too long or too short in the "_delay_ms()" calls.

Hope this helps.

And don't forget to post pictures, when you are done ;)

Cheers,
Alex

[tristanr]

Also, I'm unclear about what the reference resistor value should be ((R2 on the schematic). The LDR I am using is approx 5 kOhms in ambient conditions, increasing to around 40 kOhms when shaded (or, at extremes 150 kOhms when completely covered, and 0.5k Ohms held right next to a bright light bulb). Should I be aiming for a value of R2 somewhere within that range? Is R2 even necessary?

[alex_weber]

Hi tristanr, the resistor and the LDR should split the voltage in equal parts (oh man, I don't know how to say it better). Keyword is voltage divider, I think. Meaning, if the LDR has a resistor of 5kOhm, then you should use 5kOhm for the resistor as well. If these two values are not balanced, the range that the MCU can detect will be limited.

[electfire]

how about making it radio controlled you could program it from farther away btw really niceproject but unfortunatly I don't know C+ so could you provide the code?

[alex_weber]

electfire, take a look at step 5. There are two attachements, one is the source code (C), the other one is a compiled hex file. Cheers, Alex

[fish7days]

Nice SOS Can it use infrared instead of an LDR? Now it can be a throwie, but programmable from the ground with a remote.

[alex_weber]

I think you can. Be sure your remote is powerful enough. Photos already?

[The Real Elliot]

Really nice! And I love your free-form, standup build style. I'm going to have to make one this weekend. Was wondering what to do with all the tiny photocells I've got lying around...

[alex_weber]

Cool, and don't forget to post a photo or a link ;) Cheers, Alex

[mritter]

Thanks a lot! It's surprisingly difficult to get simple example code for the Tiny13. As for the German site, remember that Google Translator can do entire webpages! (Actually, when I tried it, only about a quarter of the page was translated, but you could do the rest of it piecemeal if you really wanted).

[joe57005]

it's be cool if someone built a bunch of those as throwies, put them on a wall and program it with a big 'ol projector. (like a giant animated throwie mural)

[thoughttrain]

Hey Alex, Great stuff. My projects are very similar. It feels good to find others on the same path. Where do you live? I'm in Philadelphia (US). I am developing some very simple automation for Mom and Pop shops. The automation is simple, modular, and will be usable by non-tech-savvy folks. I borrow a lot from genetics and biology in my thinking. Are you involved in any commercial products? Feel free to email me ([e-mail]). Peace, Tom Welsh Philadelphia

[Jonathan_Clift]

Hello Alex,

I think you meant to say that PB3 is set high when you take a measurement, not PB2.

Also, the resistor formula is a bit confusing as it stands. Might be better as:

R = (Supply voltage - LED voltage)/0.002

It's also worth noting that although red and amber LEDs generally have a forward voltage of something like 1.7V at a current of 2ma, high brightness green, blue, and white LEDs have a much higher forward voltage (over 3V).

[alex_weber]

Hi Jonathan, you are right, I changed it. Kind regards, Alex

[danwinkler]

I really like it. Having a problem though. When I compile main.c in AVR Studio 4, and then try to download onto the attiny13, it says that the .hex file is too big. I can download flickled.hex straight onto it, but then it doesnt work. Help?

[alex_weber]

Hi Dan, maybe you can adjust the optimazation flag. I am not familiar with the AVR Studio but for AVR-GCC the flag is -O0 to -O3, where O3 optimizes most. There exists even -Os for space optimazation. Or maybe you have compiled with debug informations which consumes additional space. HTH Regards, Alex

[dave_chatting]

Hi Alex - did you see drskippy's version - very cool:
http://drskippy.net/blog/2007/04/picbased_programmable_led.html

Dave

[alex_weber]

Hi dave, thanks for the link. This version is awesome!!! Kind regards, Alex

[alex_weber]

Here is another version of the programmable LED, done by Tod from todbot.com.
Smart LED Prototypes
He uses an RGB LED and a touch sensor. Very nice.

[dave_chatting]

Hi Alex - this is a great project - I'm building my own right now - in fact I'm planning to build 25! Looking at your breadboard in the second picture it doesn't seem quite the same as your schematic in step 3 - for instance the LED are wired into pin 7 here and from pin 6 in the diagram. Can you help me out? Many thanks, Dave

[ph0rkeh]

Yeah, I was also just looking at that as well... I dont plan on making one but im always interested at looking at other developers projects... and I see alot of inconsistency's like for example: in source it says LED_BIT is 2, and commented he says thats PB2. when in the schematic the LED bit is clearly PB1. and the LDR is clearly connected to ADC2 witch is pin 3 in the source, but schematic tells a different tail... from what I can tell the image above is the correct placement, if you try to follow the schematic you will fail, its way off

[dave_chatting]

Hi - I've made my fist one now - seems to be working well. This is my circuit diagram. Cheers, Dave

[alex_weber]

Hi Dave, I am sorry that my schematic was misleading. It was made after the actual project. Do you mind if I take yours to replace mine? And great that it works for you. Do you have a picture? Kind regards, Alex

[dave_chatting]

Hi - certainly, very happy for you to use it. This is a photo of my version, the next one I try I'd like to go for something more organic. I'd like to end up with a whole crowd of them - all slightly different. Wondering about using a flex sensor instead of the LDR... I'll put all my photos on Flickr. Cheers, Dave

[alex_weber]

Hi Dave, schematic is replaced. And cool version. Keep posting pictures of the organic version. I would love to see them. Cheers, Alex

[dave_chatting]

Just finished my second version... I'm posting them to flickr: http://www.flickr.com/photos/dave_chatting/tags/instructables/

Not very organic yet!

Cheers,
Dave

[alex_weber]

Hi Dave, the new one just looks great! Nice sculpture and nice picture. I like really it. Do you use the battery as mirror? Cheers, Alex

[dave_chatting]

Thanks! Yeah - the battery reflects the LED light at the moment. Wondering about uses it for the LDR instead. Dave

[Neodudeman]

Reminds me of a Pummer Beam Bot

[mungewell]

Hi, Great project.... I was thinking along the same lines but am far too busy to actually do anything about just now (or some other wimpy excuss like that). I assume that you have a learn 'code' (particular sequence of light/non-light) for placing the device into learning mode. I have a few suggestions which you might like to consider. 1). Implement a 'sync' and 'stop' code - would enable control of multiple devices together in an array. 2) If not already do a 'learn for x seconds' - you could then use a video projector to teach a 2D (think vertical strip which uses eye scan to build 3D image) or 3D matrix of devices. 3) Daylight mode - use the sensor to detect when it is daylight and turn LEDs off to save battery. You could even play with the idea of devices putting out the same codes to 'virually' infect others with sequences... Anyway very cool project, congratulations - you even inspired me to register. Simon.

[alex_weber]

Hi Simon,
have a look at Synchronizing Fireflies if you like. It's about infecting each other, in a way.
Regards,
Alex

[al-yazdi]

Hey, same as me, I registered for this project ...... And this is really really amazing ! It could be really nice too, seing what does some of them do when putted in a black chamber together ...... Would you think they would ........ invent their own language ? ... I'm quite ready to do a matlab (scilab) simulation ...... Once again ! How couldn't have I missed something like that before !!! Ben

[alex_weber]

Hi Simon, the programming mode is active for some seconds, as you suggested. The daylight mode is missing, but would be easy to implement. Letting devices infect or react on each other is something, I am already thinking of for a long time. It must be fun to look at it. Maybe i'll try that. Regards, Alex

[ph0rkeh]

I love the whole idea of this little project, simple and neat! but one question after looking at this image, why do you have a socket on your breadboard? why not just connect the AVR to your breadboard... I do.

[alex_weber]

You are right. I haven't thought of it. X-) Regards, Alex

[Foxfur]

For those who have little or no microcontroller programming experience (I include myself in that group), I'd reccommend Microchip's PICkit 1 FLASH Starter Kit. Digikey has them for $36 and ship worldwide. Digikey lists it as Part Number DV164101-ND. It comes with an 8-pin uC, but will program 8-14 pin PIC chips. The kits come with software including a programming environment. The board has buttons, LED's, even a pot or two, so that you don't even need an external item to interface with when beginning.
Click here for a priced list of the available PICkits and daughterboards at Mouser.com.

I just learned that a 'PICkit 2' is now available. Mouser has it for $34.99, $1 less than they price the PICkit 1's out at! Seems that DIY DSP is headed our way...

Click here to view the PICkit 2 specifications at Microchip's website.

I also have a Zilog Z8 Encore! starter kit that is along the same lines as Microchip's offerings.
Most every uC manufacturer carries or offers a beginners kit to get folks like US to discover the ease (?) with which one can implement the devices.

It used to be that there were only 'Developers Kits'. These kits were designed for a seasoned propellerheads (engineers) with every imaginable option included. Price? ~$2,000 - $10,000!!!

Nowdays, some uC mfg's are distributing their newbie starter kits using the 'developers kit' moniker, just to confuse issues. But YOU won't be confused. Why? Because you are INSTRUCTABLE :) !

I'd throw more links in, but I've gotta get back to work...
Ff

[Foxfur]

Just wanted to add a note about my post.
I realized that I didn't say squat about the uC being used in this elegantly simple Instructable.
The Atmel ATtiny13 device family page is HERE.

Atmel indeed has a starter kit for the ATtiny's, the ATSTK500, which can be examined HERE.

You can purchase the ATSTK500 kit at Digikey for $79, (Digikey Part Number ATSK500-ND). Mouser does not carry it.

Just wanted to be sure to at least mention a kit that is related to the uC involved in this Instructable.
Ff

[Kiteman]

If you are a total newbie to programming chips (like me) and a bad solderer (like me), then (I think) this could be done with the "picaxe" system ( http://www.picaxe.co.uk ).

You could do the free-form version with a chip holder, to save the chip from clumsy-soldering heat damage, and include the serial download socket in the circuit, then the chip can be programmed and re-programmed in situ.

[Fenwick]

I would just like to add that the main shot of this instructable is amazing. It just looks awesome free-standing like that.

[chadd_from_pa]

Here is an article about custom programmable LED controllers using the PIC Micro: http://www.lunaraccents.com/technology-programmable-LED-controller.html

[endolith]

With surface mount components and some soldering practice, you could get this into a really small volume.

[Nawaz]

Hi, Does the 'mymultiprog' supports others microcontrollers such as the PIC 16F84 , 16F84A ,etc.... By the way COOL PROJECT.Was thinking to build 1 but I still don't have my PIC programming hardware and also I am new to PIC programming.

[alex_weber]

Hi Nawaz, the myMultiProg programmer supports all version of AVR controllers from ATtiny to ATmega but it is not able to program PICs. I am not familiar with PICs but I am quite sure that the schematic should be adaptable, as well as the software. Kind regards, Alex

[manuka]

(removed by author or community request)

[alex_weber]

Hi manuka, the ATtiny13 is also DIRT CHEAP if you wish. I bought mine for 0.99€. 10 will cost 0.89€ and 25 will cost 0.79€ (~1US$). That is much MIPS for the money. Regards, Alex

[Forrest]

I agree with manuka on this one. The difference between the ATiny 13 and the Pixaxe 08 or 08M is you can program the Picaxe chips using nothing more than 10K and 22K resistors connected to the serial port and the Picaxe programming software is a free download from www.picaxe.com

[Kronaxi]

If you use the parallel port, you can simply connect specific pins to the microcontroller (this is considered a direct avr parallel access cable -- doing a google search for DAPA will bring up info on it.) In theory, you should use resistors (if you use more than 4v), but as the power requirements on AVR's are rather versatile, you can get away without them. If you do not have a parallel port, there is also a DASA (direct avr serial access) cable, though I can't seem to find as much documentation on it.

[joakimk]

Cool idea! Here's my immediate thought: Would it somehow be possible to remove the LDR entirely, and simply use the light-sensing abilities of that one LED to record the new sequence? For instance, inn between flashes (ie, when it "displays" a shadow), the atmel chip could poll the diode and see whether anyone's shining light on it...

[RichardBronosky]

Seems like a small tweak to the code could insert a "bright dark bright" sequence into a random location in the playback. Then you could put a few of these in a dark room and they would "learn from each other." It would be like a living art display. That thing looks a bit menacing. I hope it doesn't decide that we should be entertaining it. I'd sure hate to see such a cool project turn into SkyNet.

[Kiteman]

This looks really cool, and seriously tempting, but I have never used programmable chips. Do you programme the chip before you solder it all together, or do you connect it to your PC somehow (croc clips?) and programme it after the build? Can you recommend equipment/software via an English-language website?

[alex_weber]

Hi Kiteman, for this one you have to program before you solder it. If you are new to microcontrollers, I would recommend to use some kind of demo board. Search for "avr" and "butterfly" for example. Regards, Alex

[WardXmodem]

I went to a local sci-fi convention, because I heard they were going to have a "blinky" session, in which you buy a blinky (a battery powered, MicroChip PIC powered LED device) for <$10 and put it together.

I had a blast, and they are available as inexpensive kits for those that want to play around.

The blinky you get is pre-programmed, with various patterns. There are linear (19 leds), circular, 5x7, and recently 4 RGB color LEDS (so they could make "any" color by duty cycle pulsing).

For <100 you can get a programmer for these PICs, and hook to USB and program your own. Buy additional chips (such as from DigiKey or Jameco) for a few bucks.

http://www.2dkits.com

[gzusphish]

AAAAHH...I bet a bunch of these put REALLY close together would make some cool, self-replicating patterns especially in darkness cuz their flashing LEDs would affect each other.

[el eliel]

i used to do this with a bunch of highway flashers equipped with photo sensors. hours of fun, but be sure to take your epilepsy medication before trying this...

[DonTron]

Here is the simplest manifestation:

[DonTron]

I made something akin to a bunch of these for a chaos generator, years ago, I'll have to go in the garage and dust it off for you guys this summer. The sensor you have chosen to use is broadband, which in the singuar case is okay. An alternative is to turn an LED into a photo-diode. This will have a sensitivity peak at its emission frequency. What one does, is configure a Norton amplifier for high gain. Say, a transresistance on the order of 10^{6 for red, nearer 10}7 for blue. If one isn't too concerned about bandwidth, he can use an attenuator network on the negative feedback section of a singular op-amp to achieve this. The direction of the diode doesn't matter much in this application, a rare situation. Cascading a voltage amp after the Norton amp is another possibiltiy, basically squaring the gain-bandwidth product of the single amplifier, noise is hard to avoid at these gains, regardless. A cascade of LNAs would probably work best. My circuit modulated an astable, using aforementioned sensors, their emitter, however was broadband, a light bulb, this provided thermal integration making the circuit chaotic rather than just noisy or phase-locking. Let me put in a word for the MSP430. It comes with a really good C++ compilier and much better hardware than most small controllers.

[dmacrae]

I really like the formless layout of the microcontroller, I have been tempted to try this with one of my projects but have been holding off because i have never seen it done.

[gfixler]

I want to teach it the sequence from "Close Encounters of the Third Kind!"

http://www.youtube.com/watch?v=tUcOaGawIW0

[clickykbd]

This is pretty great!

[rockyt]

Cany someone remind me how I add this to my favorites?

[jeffreyf]

Just click the plus button on the top right.

[thewoodcarver]

Well done !!

[rockyt]

can you provide a link to where you purchased the AMTEL chip, all I find on digikey and mouser.com is the attiny12v and attiny15v. And I don't see any of the 8 pin variety. thank you. I like the instructable. It's very cool!!

[sethj]

sparkfun.com has them

[alex_weber]

Hi rockyt,
I bought mine here http://shop.embedit.de/product__258.php. They ship in germany only I think. Sorry, I don't have another link.
Regards,
Alex

[bill.schuller]

I like your use of "twist ties" for breadboard jumpers. I never would have thought of that...

[alex_weber]

Yes, you recognized them? I had all materials together but the suitable wires were missing. Damn! The "twist ties" fit perfectly.

[purkolator]

Is it just me or is that a couple of bread twist ties jumping the power rails in the 2nd breadboard picture. If it is... kudos on a unique recycling job.

[alex_weber]

Thanks to all of you for your kind comments. Putting more than one together and letting them interact is a nice idea. Maybe my next project ;)

[sysadmn]

Excellent project - clever idea to make it 'learn'. Now if we combine this with the resistor man sculpture... A robot that winks back at you!

[crapflinger]

extremely nifty!

[mje]

I love it. I'm imagining a poster or wall sized array of these that would respond to shadows and lights falling on it.

[xboxteen01]

awesome

[HamO]

dittos to robonut625....lets see more from you. Love the look of the finished product. Excellent, thanks for sharing.

[robonut625]

I love this kind of project... simple, cheap, and performs a single function well! You've done a good job, alex! Hope to see more quality projects from you in the future!

[andorphin]

That is extremely elegant and looks like a great desk ornament. Kudos sir!

[theformatter]

for a 1st instructable, you've done a pretty good job. I gotta try this one out, it looks simple, fun, and should help me teach the kids somewhat about electronics.

[Magnelectrostatic]

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