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Finally managed to get the persistence of vision working with thanks to Mario (who spotted a bug in my code) and Stefan (who threw some demonstration circuits together). Still working on the software and maybe a little bit of hardware tweaking - the power regulation get's hot when all of the LEDs are on. For the story so far have a look at the Wiki page.
So a few weeks ago I started out with this:
and the challenge was to come up with something, just something, not necessarily useful. So I decided to have a go at making an LED cube to see if the Mini had enough performance to give the illusion of a constant display.
So a few weeks (and a lot of solder) later I had:
and a controller board to make.
A few minutes ago it finally all came to life:
Each of the rows is made up of 64 LEDs and there are 8 rows (512 LEDs). There are only a maximum of 64 switched on at any one time (i.e. one horiontal plane), so the picture above has each plane being switch on and off one after the other with a data change between the switching.
Sorry it's not a video - I'll get around when I have an interesting animated display sorted - just kind of pleased to have got this far with no major mistakes or burns !
Mark,
That's really cool! I've been wanting to make a huge LED Cube for Netduino for ages. Videos, please!
If you can put up some how-to's, we'll be happy to tweet about your cube...
Chris
I think I saw something similar, but it larger scale in Zurcih HB station made by ETH Zurich students. If I remember correctly it's called 'Super Nova', it's a full cube, but it's huge. It has colors and and there is transperant touch panel to control it. You can even watch movie clips on that thing!
Nice to see this LED Cube! Keep us posted
Mark: the picture looks awesome, but it does not render grace to the light effects.
Could you take a video with some game of lights?
Congrats for the idea (and for the patience as well)!
Cheers
Biggest fault of Netduino? It runs by electricity.
That's really cool! I've been wanting to make a huge LED Cube for Netduino for ages. Videos, please!
If you can put up some how-to's, we'll be happy to tweet about your cube...
I was planning on putting something in the Project Showcase (and on my blog) when I'd finally finished and satisfied myself that there were no hidden glitches.
Videos will follow when I have the software sorted out. Will be interesting to see how far the processing power can be pushed.
I think I saw something similar, but it larger scale in Zurcih HB station made by ETH Zurich students. If I remember correctly it's called 'Super Nova', it's a full cube, but it's huge. It has colors and and there is transperant touch panel to control it. You can even watch movie clips on that thing!
Have a look at these guys - seekway.com.cn - they have some awsome LED displays. I tried to get my wife to agree to the 32,768 LED cube as it is only four times bigger than the one I'm working on. I guess I'll have to stick with the 8x8x8.
Mark: the picture looks awesome, but it does not render grace to the light effects.
Could you take a video with some game of lights?
Congrats for the idea (and for the patience as well)!
The picture does leave something to be desired but better images and videos are planned when I get the software written.
In fairness, the concept was not mine, the design was but not the concept. As for patience, that's a lot of joints !
So far it's been fun and there is still more to do:
- Update the regulator as it get's hot when all the LEDs are on. I'm leaving this until I have software which needs a large number of lights on at the same time.
- Software
- A case
Mark, I'd curious about the schematic, just 'cos you mentioned the regulator getting hot.
Could you post something about it?
The power is suppled by a standard off the shelf supply delivering 12V @ 2A. I then feed this into my own regulator board which is nothing too fancy and was knocked together to get the project going (I don't have access to a lab power supply at the moment).
The regulator board is simply a couple of capacitors (1000uF on the input and 100uf on the output) and a 78S05 regulator between them with an LED and resistor acting as a power indicator. i.e.
12V in -> 1000uF between ground and 12V -> 78S05 Regulator -> 100uF between ground and 5V output -> 5V output
I think the problem is that with all of the LEDs on I am driving the regulator close to it's limit. It's rated at 2A and with all the LEDs on I am drawing 1.6A (64 LEDs @ 26mA). That assumes all of the components are perfect - which we know does not happen.
I always knew I would have to replace this part once I had demonstrated the theory worked. For a start it is inefficient.
Managed to get a small amount of time in front of the keyboard this evening and had the chance to write a simple demonstration program which cycled through the three planes and moved them through the cube.
The code splits the cube into horizontal planes and uses 8 bytes to represent each of the planes. Each bit then represents one LED in the cube.
Moving from the bottom to the top of the cube - this does not really show the persistence of vision as it is simply a case of setting all of the bits in an eight byte section to 1 and then showing that section. It still uses the same driver code though.
The remaining two planes do show that the persistence of vision can work as it requires the system to set the bits for a small part of the entire cube and then move on to the next horizontal plane and show the next sequence of bytes.
So here is the video of it working:
Pixar have nothing to fear
Next step, some more interesting animations and possibly start to write up the work so far.
Regards,
Mark
One final video before I start to write this up. Here the cube demonstrates the following:
- Bouncing a plane from the back to the cube to the front and then back again
- Spells NETDUINO
- Bounces a plane from the top of the cube to the bottom and then back again
- Rains a little
- Clears the cube with a wipe effect
- Bouncing a plane from the back to the cube to the front and then back again
- Spells NETDUINO
- Bounces a plane from the top of the cube to the bottom and then back again
- Rains a little
- Clears the cube with a wipe effect
Mark, very good job!
The circuit part is well designed also.
The next (potential) step would be to refine the project. Design a "module" (e.g. 4x4x4 leds) totally autonomous, that can be assembled easily as it was a Lego-brick. The Netduino connections should be well-defined, so that connecting one or ten modules has no matters?
Will the Gadgeteer interface be able to do this?
I guess it could be nice idea that would meet many people...
Cheers
Biggest fault of Netduino? It runs by electricity.
