Help with an AVR version of the POV Display

Post here to discuss the 8x85 RGB LED POV Display.

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Help with an AVR version of the POV Display

Post by brad » Wed May 11, 2011 4:37 pm

I have moved this post here to give it it's own topic.

Here is the original post:
hi Brad,

I enable the RESET pin of the ATmega16L after every display of my frame so I have got rid of the garbage values. Now I get the required colors on the LEDs for the output which reads "ROBERT". But when I tested it on the ceiling fan I could only see the colors but not the letters. The letters were just not appearing. :shock: :cry: Could it be something to do with the delay when the LEDs are ON "as well as" OFF?? :idea: :?: :?:

Another problem is that I had prepared the circuit on the breadboard and I mounted the breadboard on the fan in spite of knowing that the wires would come out (and a few did come out, but I was just too eager to test it). :roll: Now I wanted to prepare the PCB version of the circuit for further testing but am discouraged by a friend about preparing the PCB yet. He says that I'm not getting the letters maybe because of some mistake in the circuit (although I think otherwise since I feel that if he was right then i wouldn't be getting the right colors on the LEDs). The LEDs flash with the right colors but the letters just don't appear.

What do you suggest? Is it OK if I prepare the PCB? Where do you think does the problem lie?

Thanx in advance. :)

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Re: Help with an AVR version of the POV Display

Post by brad » Wed May 11, 2011 4:42 pm

My first thought is that you are not flashing the LED's fast enough. They need to be flashing so fast so that when it is not spinning, you should not be able to see the transition from one column to the next)

When you say that you can make out the word ROBERT from seeing it flash through the sequence, but the only way you could make that out is if you had the flash speed set very very low.

So, I think that all you need to do is decrease the delay between each column in the word ROBERT.

A good visual aid here is one of my old video clips. Have a look at the LED's before it starts spinning, they are flashing so fast that you can't possibly make out anything! but when it speeds up, this is where your eyes start to see a different 'flash' in a different position which draws the image.


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Re: Help with an AVR version of the POV Display

Post by robertrndya » Wed May 11, 2011 6:25 pm

hi,

and thanks for giving me my own topic. ;)

OK, I did decrease the delay between each column before testing it. But maybe I need to decrease it further. But its not the circuit fault right (like my friend suggested)?? Should I go ahead with the PCB version for further testing? And should I try putting some delay when the LEDs are OFF as well?

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Re: Help with an AVR version of the POV Display

Post by brad » Thu May 12, 2011 9:12 pm

Are you able to upload a video of what happens on youtube? This would really help me with troubleshooting your problem before making a pcb for it :)

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Re: Help with an AVR version of the POV Display

Post by bitfogav » Fri May 13, 2011 1:18 am

So its an AVR version of the POV display?, just out of interest are you programming your Atmel using C language or AVR Assembly?.

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Re: Help with an AVR version of the POV Display

Post by robertrndya » Fri May 13, 2011 3:12 pm

Hi Brad,

I'm really sorry but i don't have a video of it, and I have disconnected the breadboard connections. :o :shock: :roll: :(

The display was like only colorful lines. Yesterday I had done all the connections back again on the breadboard, but then when my friend tried to test the output by moving the led board with his hand he pulled out quite a few more wires, much to my dismay. So out of frustration I thought I'll prepare the PCB.

And yes Bitfogav, mine is an AVR version of the POV, and I program my ATMEL using C language.

And Brad, SORRY again.

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Re: Help with an AVR version of the POV Display

Post by bitfogav » Fri May 13, 2011 6:51 pm

Very interested in seeing your POV when you get it working, and if its possible i'll like too see your C code too, as ive just been learning some AVR C, maybe we could help eachother or come up with some ideas for your POV displays. :)

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Re: Help with an AVR version of the POV Display

Post by brad » Fri May 13, 2011 8:17 pm

Ithink you should be right to make your Pcb. You said that you could get it to flash what it needed to flash so maybe a nice sturdy circuit board will help when it is spinning rather than having plug in wires to a breadboard.

Let us know how you go.

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Re: Help with an AVR version of the POV Display

Post by robertrndya » Tue May 17, 2011 3:05 pm

Hi Guys,

I've been a lil busy these past few days. Anyways, my PCB is under construction now. Actually, I'm doing the circuit on a Veraboard.

I was thinking of making a provision for IN-CIRCUIT-PROGRAMMING, using the USB to Serial Converter that I have. I found a simple circuit on the net which uses only 3 resistors. I tried it on the breadboard but it failed. :roll: The device itself couldn't be found, so there was no communication taking place. :x

I found quite a few circuits for parallel port programming but my laptop doesn't have a parallel port. :( So I need to program it via the USB port. Can you guys help me out with this please?? :|

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Re: Help with an AVR version of the POV Display

Post by bitfogav » Wed May 18, 2011 2:30 am

Let me get this right? you want to make an in circuit programmer for your POV pcb (veraboard?).

Also what are you using at the moment to programme your AVR microchips?.

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Re: Help with an AVR version of the POV Display

Post by brad » Wed May 18, 2011 6:12 am

A USB to serial converter using only 3 resistors? Could you provide a link to this?

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Re: Help with an AVR version of the POV Display

Post by bitfogav » Wed May 18, 2011 7:04 am

Heres an in circuit serial for AVR.
avr_programmer_serial_connector.jpg
avr_programmer_serial_connector.jpg (30.13 KiB) Viewed 18264 times
avr_programmer_schematic.jpg
avr_programmer_schematic.jpg (14.92 KiB) Viewed 18264 times
all the info can be found here:
http://electronics-diy.com/avr_programmer.php

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Re: Help with an AVR version of the POV Display

Post by robertrndya » Wed May 18, 2011 3:10 pm

no no.....not a usb to serial converter using 3 resistors. The programmer circuit has only 3 resistors and one end of the circuit goes to the microcontroller to be programmed and the other end goes to the female connector(RS-232). Now since I don't have a serial port on my laptop I'm using a USB to serial converter.

The link to the circuit that I mentioned is: http://pavanreddi.wordpress.com/2010/10 ... r-circuit/

I had found 1 more, but I still have to try it. The link is, http://diy4fun.blogspot.com/2009/01/sim ... r-avr.html

And yes I want an In-Circuit-Programmer for my POV PCB, not the veraboard. I'll be making a proper PCB for this, the veraboard is just for getting everything right (Fine Tuning as I call it).
Thanx for the link btw. :) I'll try it

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Re: Help with an AVR version of the POV Display

Post by robertrndya » Wed May 18, 2011 3:43 pm

hey Bitfogav,

About the circuit that you menitoned to me, does it work for the ATmega16L?? :?: :!: :?: :!:
Because previously I had purchased an AVR programmer online from Robokits. It worked fine for the ATTiny2313 but when I switched to the ATmega16L it started giving problems. It wouldn't detect the device. Then I started using the Unipro9U Universal Programmer at my old College.

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Re: Help with an AVR version of the POV Display

Post by bitfogav » Thu May 19, 2011 3:13 am

Hi, looking at the software that I posted above on the link doesn't say it supports a ATmega16L?. so I cant be sure if it does or not. Any how "PonyProg serial device programmer" software seems like a old piece of software, So I doubt it will?..

If im honest I wouldn't waste any time making a serial programmer for AVR, I recommend buying a AVRISP mk2,
It should programme any Atmel microchip and also supports any new Atmel microchips that come out in the future, as the device will automatically update when new software comes out for it, also it connects via USB (so you dont need to have a serial adaptor)

Heres where you can get a AVRISP mk2
http://www.atmel.com/dyn/products/tools ... ol_id=3808

The other thing, you want to make your pcb POV programmable?, well all i would do is put a AVR programmer socket on your designed PCB and programme the Atmel microchip via this connector. for an example a connector like this, obviously you need to design your PCB with this connector connected to the programming lines etc of your Atmel microchip.
avrConnector.jpg
avrConnector.jpg (10.27 KiB) Viewed 18257 times
Also Im not sure what you are using to programme your Atmel microchips with at the moment but I recommend AVR studio 4 or AVR studio 5. both of them work with the AVRISP mk2 programmer I recommended above. And both of them are free :)
http://www.atmel.com/dyn/products/tools ... ol_id=2725

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