I am trying to build an RGB 4x4x4 led cube using an Arduino Duemilanove but have been strugling to find appropriate source driver chips for the anode bunches. I plan to light only one color per column at any one point in time and was planning to use 4 cascaded 74HC595. So basically one chip would need to source 8*0.20mA = 160mA. But from what i understand, the '595s can only source a maximum of 70mA total. I was really hoping to avoid having to use a high-side switch, could someone please guide me in the right direction.
I found this link
Its a little dated but seems to use a 74ACT541 for sourcing column current. Can someone please let me know if this might work?
Many Thanks and apologies any naivety in the post.
thank you mike. the 2981 was going to be my next question. would be really greatfull if you could also help me understand how do i hook this up with the arduino.
I mean i am currently using a 1A 12v constant output wallwart to power the arduino. Can i use the +5v port from the board to power the 2981 or do i need a completely different wall wart with perhaps a seperate regulator like the 7805 to power the driver?
apologies for being all over the place, i kindda new to this and again many thanks for your response.
no worries mike. I am extremely thankful for your quick response. so i can go with either of the drivers. just one last question and my be i misphrased my requirement, i plan to use 4 such drivers (assuming each is 4 channel) to be able to power one entire layer (i.e 16*0.20mA = 320mA) at a time.
Would this setup call for a seperate power source? And if yes, do you think it would be OK to just use another parallel connection from the existing 12v wall wart (not going thru the board) into a 7805 to power the drivers (i was reading somewhere that a 7805 perhaps will get too hot a 1A)?
also could you confirm that the onboar reg can handle upto 320mA. was reading another post that said that the regulator on the duemilanove is rated for 800mA bt i can get 500mA from it. If this is accurate i think i dont have a choice other than using another regulator (LM323?).
So that would leave one more help from you kind people here, how do i wire it up?
Just use a parallel connection from the existing 1A wall wart before it goes into the arduino board and connect it to the 323? Help and suggestions are much appreciated.
just use a parallel connection from the existing 1A wall wart before it goes into the arduino board and connect it to the 323?
Yes you can do that or you can wire the regulator to the Vin pin. This voltage goes through a polarity protection diode (rated at 1A) and is perhaps easier to wire to.
so this is what i am going to do. I will power the cube from a LM343 power reg connected to the Vin pin on the board. I will use 4 daisy chained 74HC595 to handle 48 anode bunches with high side switches (discrete transistors instead of the ULN chip) and use standard PNPs 2N2222 to sink the layers to ground (no planning on using PWM so perhaps not need the 5940). Thanks again for all the help man.