Instructables

$10 ATtiny85/45 POV display!! (works really well)

Hey guys! This is an Instructable for making your own ATtiny85/45 5 LED POV (Persistence Of Vision) display!

This is my second Instructable, also for the Elemental LED contest, so drop a comment and vote it up!

The total parts cost for this POV display is under $10! (If you get the parts from a wholesale supplier, like Mouser or Digi-Key)

I apologize for all the horribly blurry pictures, I'm using my iPod touch to take them (what a crap camera on that one, right?) I will be taking the pictures with a different camera for my future Instructables. :)
 
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Step 1: Parts List

Things you will need:

Parts:
1x ATtiny85/45 microcontroller
1x 8 pin DIP socket
1x 2 position slide switch
1x 100-220 Ohm resistor
1x 2 AA battery pack
5x LEDs (any color) (I used rectangular 2x5mm LEDs because they fit right next to each other without a gap on the perfboard)
Some bits of wire
Some perfboard

Tools:
1x AVR programmer (can be an Arduino, go here for instructions)
1x Saw or Dremel for cutting the perfboard down to size

Step 2: Circuit Schematic

Picture of Circuit Schematic
Here's the schematic for the circuit. I have attached the Eagle .sch file at the bottom.
baecker032 months ago
how would a person make the display a clock?
Fanima Dekoi8 months ago

Great first POV project!

attiny45 NOTE: I'm using ATtiny 45
on this, and ran into a problem of memory overflow. I don;t know why,
because the 45 is supposed ot have 4k on it, but it would not do
anything, even thpough the compiler only counted about 2.5k???. The
only workaround I found to make it function was to reduce the code
size. I // commented out the all the 'if (c==' lines in the displayChar
method that weren't included in my dispay word, and it works fine. (In
the "wow! case, only the w, the o, and the ! remained un-

commented-out)
now it works. Probably not a problem with the 85. Also if using 3v,
you can probably use less of a resistor (or none, I have mine jumped
out) because it's pretty dim with 220.

DSCN2734.JPG

Have you upload with ATTiny85 1 MHz? 8 MHz doesn't work well because it is equal to or less than 3 Volt.

Jamebonds1 made it!6 months ago

I made it with Etched PCB. It work pretty good. Don't need much wire messy and is cheapest than order custom PCB online and not need EAGLE skill since you can use black marker.

IMG_7389.JPG
Hi! I just finished your great project!
As other people commented, I also find the line pinMode(7, INPUT); in "void setup" does not anything there…
I used a 3v. button battery (CR2032) and since the ATtiny85 and the LEDs can work with its voltage I didn't used any resistor.
Just a question: do you think there is way to use the remaining PIN 1 to do something with it?
Anyone knows about it?
13 21:16.jpg13 21:16.jpg
mikered1 year ago
Worked great after I changed the DelayTime to 1

kiranrs1 year ago
I AM USING A 20MHZ ATTINY85, WILL THIS WORK, PLEASE ANS , I AM DOING THIS PROJECT FOR MY SCIENCE EXHIBITION
danielkaye1 year ago
Nice Instructable!

Couple of comments:
I think it should be pinMode(5, INPUT); not pinMode(7, INPUT); in the setup
Also it would be great to see some comments in the code (or separately) to step through the software.

Great Instructable, But I seem to be having trouble with my 4th LED, 2nd from the bottom... any idea?
xBacon (author)  UnusualTravis2 years ago
Make sure your connecting the LED the right way. Maybe you don't have the polarity right, or you don't have the right pin connected to the LED. Try replacing the LED with another one also. If none of that works, try re-uploading the code.
I realized that in your code there was a Input, When I deleted that everything now works. Thanks for the great project to make late at night, From start to finish took me about 2-3 hours
DSC_0388.JPGDSC_0391.JPG
xBacon (author)  UnusualTravis2 years ago
I'm glad you figured that out. Id that how it was in the code i posted here? because if it is and its an error, i want to fix it.
i had the same problem with 4th led, i then removed the pinMode(7, INPUT); from the setup because it did not make sense, because the attiny has only 5 pins for interface. Now it works fine. :) you should remove this
xBacon (author)  UnusualTravis2 years ago
Do you make your own PCBs? I've tried to make them myself but with no luck. If you could tell me how (PM me) i would appreciate it :)
hesynergy2 years ago
Would someone be so kind as to do a quick Youtube demo of what we are supposed to see, not the fabrication process.

Thanks,

Chas
http://www.youtube.com/watch?v=ono6w5bb4YU&feature=youtube_gdata_player
What do you see?
Hint, it's my wife's name, but very uncommon
xBacon (author)  hesynergy2 years ago
is it... malia?
xBacon (author)  xBacon2 years ago
maliya?
...but no ceegar....grin
xBacon (author)  hesynergy2 years ago
I have no idea.... mikayla?
Hint2 use you're pause button?.. A free phone answering message in MP3 format, done by me(professional actor and voice specialist) to the first one to guess it right.

c
I believe it says " MAYLA! "
Annnnndwehaveawinnnnnaaaaa!

Right you are...though There were two explanation marks. I attribute that to the spacing Of my LEDs and t'he rather limited 5x5 font.

Give me your Ideas and text of your free custom ringtone/home phone Message as an mp3, and I'll start working on it! . Reply to hesynergy@gmail.com.
close
hesynergy2 years ago
Hey, great project!


...But I can't read the obviously "modulated" blinking "WOW!!".
1. I only had common anode LEDs.... So I switched the HIGH for LOW, and vice versa.
2. It runs different speeds depending on whether I program using attiny85@1MHZ or 8MHz... Not sure if that is the problem....persistence?

Should I have changed the delay times as well?


Thanks beforehand for your speedy response.

Chas
xBacon (author)  hesynergy2 years ago
Common anode LEDs? You use 5 separate LEDs. You should have 5 cathodes and 5 anodes, so i don't see what you're getting at.

Since 8MHz is a faster clock speed than 1MHz, the code will run faster on 8MHz, therefore you will probably have to wave the device faster to see them message.
1. Having no descrete LEDs, I am using one common(anode NOT cathode) and one color of some spare Common Anode RGB-leds...thus the reversal of the digitalWrite(HIGH,LOW) scenario. Sorry I didnt mention that.
2. Actually, setting my programmer to 8Mhz runs slower than at the 1Mhz setting! I've seen this many times before in the ATtiny forums...and yes it IS counter-intuitive. I'd love to hear an explanation....but as I said, I am not sure the speed is the issue. ...UNLESS it causes the delay() Fn, to work differently/ perhaps opposite?; to what we would expect.

Thanks for your quick response.

Chas
xBacon (author)  hesynergy2 years ago
Did you get it to work?
Yup....shore did....found som spare std. LEDS AND TOOK YOUR CODE BACK TO THE ORIGINAL.....sorry for the shouting....one caveat. ...I messed up spelling my wife's name in caps.....no blinking....WTF???

Thennnnn I looked at the code and realized it only provided for lower case, and voila!!! Put her on a lazy Suzan and there it was!!

Thanks,
Chas
...And yes, I am using 5 Rgb-LEDs.

C
Sorry for the addendum, but not only a newbie...I'm OLD.

I believe you may be able to use six LEDs if you eliminate the reset pin 1 function, and use it as an additional output.... Think I've seen that several times...

I'll shaddup and wait for a response.

C
WWC2 years ago
Nice ible.
To see the POV working what do you do, wave it around?
xBacon (author)  WWC2 years ago
You turn it on, and wave it side to side. From my experience and the one I made, if I turn it on with the switch on the bottom and the LEDs on the left side, it works best if I wave it from left to right. It comes out backwards otherwise.