Help with schematic (10x10x10 cube)

Hi all.

Before I go further into this build I want to make sure I am on the right track.

I want to use 328P chip for control and will be using 74hc595 to control LED’s

After each 74HC595 I will use ULN2804A driver to take the load of them, after each ULN2804A I will Mount my current limiting resistor.

Supply voltage to each layer will be from a MOSFET or 2 parrallel transistors.

Worst scenario, each output from 74HC595 will drive 10 LEDS, that is why I use ULN2804a, but that will make it ground controlled. I just need to remember this when I build the cube.

Max current for each led is 30mA, but I am aiming to limit that at 20mA with resistors.

Can someone smarter than me (that would be everybody else but me) take a look at my attached diagram and see it it looks alright?

Thank you
Ronni

10x10x10.pdf (43.3 KB)

A project with 1000 LEDs is quite an undertaking.

Is the circuit you showed just for one layer, and is duplicated 10 times?

Have you considered that if you want all the LEDs to be illuminated at the same time, even if they only draw 20mA each, then you need to supply 20A?

1000 not so bad - we are working on a 9x9x9 cube, still at 7 layers tho. Does take a while.

With multiplexing, only 100 on a time will be on, so 2A at 20mA/LED. I tried a 2A switching regulator wallwart, wasn’t quite enough current, was getting hot & shutting off, a 4A supply worked better.
http://www.mpja.com/5-Volt-DC-Plug-Power-Supply-4A-Regulated/productinfo/18520%20PS/

Instead of 74HC595 + ULN2804, can use TPIC6C595 or TPIC6B595, high voltage/high current sink shift register, combines the 2 parts. Save on a bunch of wiring.
Still need a current limit resistor.
Assuming common cathode columns, one shift register output per column, then 100 current limit resistors are needed.
Use low Rds, logic level gate P-channel MOSFET to source current to each layer.
TPIC6C595 can be used to pull the MOSFET gate low to turn them on 1 x 1 also.

Hi all.

Yes it only shows one layer (100 leds)

I have acces to these components thats why I chose them.

When my HIGH output from 74HC595 goes through ULN2804 it becomes a LOW signal

My setup uses common cathode colums (-), that will be activated by the LOW signal that comes out after ULN2804.

MOSFETS will supply the power (+) to each layer.

I have a bunch of IRFB4710 MOSFETS, can they be made to Work? Maybe together with BJT transistors?

I like to solder, It makes me relaxed. (Diagnosed PTSD)

Besides that I can make the same thing with other IC's, am I on the right track with my setup?

Thank you
Ronni

You did make a wooden jig with 100 holes to manufacturer each layer didn't you? :wink:

No.

Will Use plastic. ::slight_smile: :stuck_out_tongue:

Its not made yet as i want to bedste sure about My schematic first.

IRFB4710 is not a Logic Level MOSFET, it needs 10V on the gate to fully turn it on.
It is also very pricey:
url=http://[/url][http://www.digikey.com/product-search/en?keywords=IRFB4710]http://www.digikey.com/product-search/en?keywords=IRFB4710
This would be a much better part and will fully turn on from 5V at the gate:
url=http://[/url][http://www.digikey.com/product-detail/en/NDP6020P/NDP6020P-ND/1055922]http://www.digikey.com/product-detail/en/NDP6020P/NDP6020P-ND/1055922

With the '7410, you will have to pull the gate to 10 or 12V to turn it full off, and down to ~0V to turn it on.
Using an NPN transistor to buffer the arduino signal can do that.

So yes, you’re on the right track.

Freaking forum - I don't know why it hoses links like that.
Search IRFB4710 and NDP6020P at digikey.com.

JohnLincoln:
Have you considered that if you want all the LEDs to be illuminated at the same time, even if they only draw 20mA each, then you need to supply 20A?

CrossRoads:
With multiplexing, only 100 on a time will be on, so 2A at 20mA/LED. .

Quite right, CrossRoads.

Apologies for any confusion/scaremongering, that my oversight may have caused.

CrossRoads:
Freaking forum - I don't know why it hoses links like that.

It's really bad. Sometimes I have to edit my posts 5 or 6 times to get links to work correctly.

nissan200sx:
Hi all.

Before I go further into this build I want to make sure I am on the right track.

I want to use 328P chip for control and will be using 74hc595 to control LED's

After each 74HC595 I will use ULN2804A driver to take the load of them, after each ULN2804A I will Mount my current limiting resistor.

Supply voltage to each layer will be from a MOSFET or 2 parrallel transistors.

Worst scenario, each output from 74HC595 will drive 10 LEDS, that is why I use ULN2804a, but that will make it ground controlled. I just need to remember this when I build the cube.

Max current for each led is 30mA, but I am aiming to limit that at 20mA with resistors.

Can someone smarter than me (that would be everybody else but me) take a look at my attached diagram and see it it looks alright?

Thank you
Ronni

Q1: Where are the Digital I/O connections for the 10 Mosfets for the multiplexed layers?

Q2: Your diagram shows 250 Ohm Resistors.
So, is this math ( watts = R X I x I ) correct for all LEDS ON?
250 Ohms x 20 ma x 20ma = 0.1 Watts per resistor
0.1 watts x 8 resistors = 0.8 watts per resistor pack.
0.8 Watts x 13 Resistor Packs= 10.4 watts
Will HEAT be an issue?
(Math error fixed on Nov 3, 2015)

Q3) What is the LED supply voltage?

Q4) You state "LED Max Current = 30ma"
Is that for a 100% Duty Cycle or a 10% Duty Cycle?

Q5) How quickly can the Arduino actually drive the thirteen (13) 74HC595 Data and Clock signals?

CrossRoads:
1000 not so bad - we are working on a 9x9x9 cube, still at 7 layers tho. Does take a while.

With multiplexing, only 100 on a time will be on, so 2A at 20mA/LED. I tried a 2A switching regulator wallwart, wasn't quite enough current, was getting hot & shutting off, a 4A supply worked better.
http://www.mpja.com/5-Volt-DC-Plug-Power-Supply-4A-Regulated/productinfo/18520%20PS/

Instead of 74HC595 + ULN2804, can use TPIC6C595 or TPIC6B595, high voltage/high current sink shift register, combines the 2 parts. Save on a bunch of wiring.
Still need a current limit resistor.
Assuming common cathode columns, one shift register output per column, then 100 current limit resistors are needed.
Use low Rds, logic level gate P-channel MOSFET to source current to each layer.
TPIC6C595 can be used to pull the MOSFET gate low to turn them on 1 x 1 also.

With 10 multiplexed layers, the On-Time is only 10% per layer.
The LED "ON' Current must be significantly increased due to this multiplexing.
At 20ma with 10% On-Time and 90% Off-Time then the LED will be dimmer
than an LED on 100% of the time at 20ma.
The LED won't be 1/10th as bright, to your eye, but it will be dimmer by some %.
Best that I can detemine is ... 10% On-Time = LED about 40% as bright.

TEST:
One LED at 10% On-Time LED + Current Limiting Resistor + Voltage
in a normally lit room or outside to see if it is bright enough before building.

Q1: Not drawn

Q2: Just for show, it will be around that.

Q3: Supply voltage is at the supply voltage symbol.

Q4: Data sheet info for LED

Q5: Faster than my eyes can see.

Its just a crude schematic, and wanted to know if I am in the right track.

mrsummitville:
Q1: Where are the Digital I/O connections for the 10 Mosfets for the multiplexed layers?

Q2: Your diagram shows 250 Ohm Resistors.
So, is this math correct for all LEDS ON?
250 Ohms x 20 ma/LED = 5 Watts per resistor
5 watts x 8 resistors = 40 watts per resistor pack.
40 Watts x 13 R-Packs= 520 watts
Will HEAT be an issue?

Q3) What is the LED supply voltage?

Q4) You state "LED Max Current = 30ma"
Is that for a 100% Duty Cycle or a 10% Duty Cycle?

Q5) How quickly can the Arduino actually drive the thirteen (13) 74HC595 Data and Clock signals?

I have access to FQP27P06 that I will use together with 2N2222A

CrossRoads:
Freaking forum - I don't know why it hoses links like that.
Search IRFB4710 and NDP6020P at digikey.com.

mrsummitville:
Q2: Your diagram shows 250 Ohm Resistors.
So, is this math correct for all LEDS ON?
250 Ohms x 20 ma/LED = 5 Watts per resistor
5 watts x 8 resistors = 40 watts per resistor pack.
40 Watts x 13 R-Packs= 520 watts
Will HEAT be an issue?

Power = I2R
= 0.020 x 0.020 x 250
= 0.1W

So, I have updated the schematic.

I know all MOSFET have a common output, but they will control individual layers in the end.

Will this setup Work? :slight_smile:

10x10x10.pdf (59.7 KB)

Mosfets are drawn upside down.
Source goes to supply.

This is NOT a logic fet. A 5volt LED supply might not saturate them.
Leo..

The MOSFET outputs are all connected together - I think you want them separate so each can source current to a layer.

I assumed the poster knew that there is a mosfet for each layer.
Leo…

I Cant draw All 10 layers. One mosfet for each layer.

I have acces to them and have googled them. They are used together with BJT to make them Work with arduino 5 volt signal.

Would it help to increase the pull up ressitor?