All that to have some blinkenlights in a computercase ? That thing doesn't even serve a real purpose.
It's not a piece of testequipment.. .all it does is blink leds on a music beat...
Not just to have blinkenlights, to learn how to make blinkenlights. They're just as electronic as any other project a beginner could embark on.
You misinterpreted what i wrote.
When i suggest a 0.5$ solution in the form of a 7805 that is considered too much trouble...
Yet embarking on a fairly complex bit of fft code and a led matrix scanni, building a new led matrix , learning how to write code, get a dspic , make aboard for the display .. That is not too much trouble...
Especially after the ranting about 'not being avle to learn programming'.
That's the bit that doesn't make sense to me....
I'm all for learning and tinkering with electronics. But the amount of 'lip' we got in this topic when trying to suggest even simple thing like a lowpass filter or the 7805 ... It just makes me wonder.
Every other post we were met with : i don't have ( pick your choice ) money, tools, transport, knowledge, skill, brains ...
Yet, there was money and transport to get this nonfunctional 'hood ornament' in the first place.
And now we are embarking on something that will require tools,knowledge and brains as well..
What's goingto be next ? I live in the jungle and there is no electricity ?
There will be soldering involved... You will have to construct that 32x32 array of led's. either design you own board or do it on perfboard. You cant do that using two planks of wood and three nails...
Now, on a more constructive note.
If you wantto keep the pincount low: do the column addressing using a shiftregister. Just clock a single 1 around. I would make shift registers out of 74574's. the pins are neatly in order.
Tie the clk lines together. Connect the q0 to D1, Q1to d2 and so on. The last q7 goes to d0 of the next one.
Now all you need is two cpu pins. Set one pin low and give 32 pulses on the clk line. This erase whatever is in the registers. You only do this at startup. Now you make the pin high , give one clock pulse and make the pin low. This makes q0 of the first 74574 high. Ever new clock pulse moves this bit one position. After 32 clocks you have scanned the entire array.
The way the pins are ordered in a 74574 makes it very simple to construct the shifter.
You can connect the outputs of the 74574 to uln2803 and drive all the currentyou want.
So you can scan the array woth two pins in horizontal direction.
For the vertical you could do the same approach. There i would double buffer. Meaning i follow the shifter by a latch. I transfer the shifter contents to the latch using the same clock edge that progresses the scan shifter.
With 5 or 6 pins you can control the array.
Hook that into an interrupt handler driven from an internal counter and you don't need to think about it.
The fft generates 32 numbers ( one for each column) the int handler simply reads them one by one and advances the scan counter. Every interrupt you update one column. This will give you plenty of computing throughput.
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