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Topic: My 3x3x3 and 5x5x5 LED cube (Read 10962 times) previous topic - next topic

CrossRoads

Nice job with the build and assembly Wondertiger.
What current are you seeing from the 74HC595 outputs?
Set an LED high and measure the voltage across a 220 resistor.
I'd expect something like 2.8V/220 = 12.7ma if your LEDs have a Vf of 2.2V and you're actually gettiing 5V out of the 74CH595.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

WonderTiger

#46
Feb 18, 2013, 11:37 pm Last Edit: Feb 18, 2013, 11:39 pm by WonderTiger Reason: 1
I did a measurement with a cheap digital volt meter and it came around 2.5V. I think I should invest in a better multimeter in the first place (a buddy of mine has an industrial fluke that works really well he said, maybe I should look for something like that) to get some accurate readings  :smiley-red:

retrolefty


I did a measurement with a cheap digital volt meter and it came around 2.5V. I think I should invest in a better multimeter in the first place (a buddy of mine has an industrial fluke that works really well he said, maybe I should look for something like that) to get some accurate readings  :smiley-red:


There are many reasons one might want to upgrade to say a fluke DMM (I own 3) but for the kind of stuff your doing with a typical arduino project a simple cheap DMM (unless defective) will not be a big deal as far as accuracy goes. Like any tool, it's not so much the tool but rather knowing how to use it properly and understanding it's limitations. The biggest draw back of modern DMM is that it always displays a number even when the number being displayed doesn't mean what you might expect it to or want it to mean. Measuring the output of a active PWM pin is one example of a improper measurement for a DMM, it will display a number but it doesn't mean what you think it means.

Lefty

WonderTiger

#48
Feb 18, 2013, 11:55 pm Last Edit: Feb 18, 2013, 11:58 pm by WonderTiger Reason: 1
I absolutely agree with the statement you made. However I think a good meter will be a good investment though (for my study and other projects in the future) even if it isnt really meaningful for now yet.


CrossRoads

#49
Feb 19, 2013, 12:00 am Last Edit: Feb 19, 2013, 12:02 am by CrossRoads Reason: 1
I use an inexpensive Extech (extech 330) meter that seems to work really well. You don't need to go overboard with an expensive Fluke meter.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

retrolefty


You're absolutely right with the statement you made. However I think a good meter will be a good investment though(for my study and other projects in the near future) even if it isnt really meaningful for these kinds of projects yet.




I agree mostly about good test equipment being a near lifetime investment that will pay good dividends for a long long time. After working for decades in the electronics industry I found that fluke meters and tektronix scopes were all I ever wanted to own for personal use.

But the point is that arduino beginners should be encouraged that their first purchase to make after their arduino board is a DMM, well before obtaining any other components and/or modules for their various projects. So the $10 DMMs serve a good purpose in at least getting them started on the right path. Many young people starting out just can't yet afford the investment costs of say a Fluke meter, but can swing for a $10 DMM which is much better then no DMM at all which all too many appear to have.

Lefty

CrossRoads

We just got my son a $19 extech meter, sprung for a little extra because this one also came with a thermocouple probe.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

retrolefty


We just got my son a $19 extech meter, sprung for a little extra because this one also came with a thermocouple probe.


Cool, and if he misbehaves tell him you will use that probe to take his temperature the 'old fashion way'.  ;)

Lefty


CrossRoads

We got him a $119 Weller soldering station too, so I think he'll behave.  Off to college in the fall...
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

retrolefty


We got him a $119 Weller soldering station too, so I think he'll behave.  Off to college in the fall...


What, no pocket protector? What will the other nerds think of him?

Lefty

CrossRoads

Going to RPI, whole schoolful of engineers. Kids are too cool for pocket protectors these days.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

WonderTiger

Been a while I posted something here. Last weeks I was very busy with school (we are developing a weighing scale). However I managed to make a very easy animation for my cube :), enjoy:

http://www.youtube.com/watch?v=9A1HSdPkN8A

Hey Mike!

Nice video :)

I've recently built a similar 4x4x4 cube. I'm having some trouble with ghosting on the cube (it seems that the cathodes are not turning off quickly enough). The way it manifests is that when I turn on a pair of a new anode plane and a new cathode column, the LED which at the intersection of the new plane and the old column, lights up for a brief moment. This results in ghosting. It is most likely a hardware problem, but I want to make sure that it's not a software problem. Have you had any kind of similar ghosting problem? Would it be possible for me to see your code, maybe I'll get some insights about what I might be doing wrong...

Thanks,
Andras
Andras
http://iqjar.com

WonderTiger

#58
Mar 08, 2013, 02:42 pm Last Edit: Mar 08, 2013, 02:46 pm by WonderTiger Reason: 1
I have not seen 'ghosting'on my cube. However if I light up 1 layer, the layer above the lit one will shine very dim. But this is due the light goes through the bottom of the LEDs.


Yes, I have the shine-through effect too, but that's not a big problem and there's not much you can do about it anyway. Thank you for the code! :) I will check it.
Andras
http://iqjar.com

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