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Step 4Building the controller board
How to build the controller board and attach it to your Arduino:
Follow the schematic and build the board however you choose. I placed the controller chips in the center of the board and use the left side to hold the transistors that control the current to each layer of the cube, and used the right side to hold the connectors that go from the controller chips to the cathodes of the LED columns.
I found an old 40mm computer fan with a female molex connector to plug it into a computer power supply. This was perfect. A small amount of air flow across the chip is useful and I now have an easy way to provide 5 volts to the controller chips and the Arduino itself.
On the schematic, RC is the current limiting resistor for all the LEDs connected to each A6276EA. I used 1000 ohms because it provides 5 milliamps to the LED, enough to light it. I'm using High Brightness, not Super Brite LEDs, so current drain is lower. If all 8 LEDs in a column are lit at once, it's only 40 milliamps. Each output of the A6276EA can handle 90 milliamps so I am well within range.
RL is the resistor connected to the logic or signal leads. The actual value is not very important as long as it exists and is not too large. I'm using 560 ohms because I had a bunch of them available.
I used a power transistor capable of handling up to 6 amps to control the current going to each layer of the cube. This is overkill for this project, as each layer of the cube will only draw 320 milliamps with all the LEDs lit. I wanted room to grow and might use the controller board for something bigger later. Use whatever size transistor fits your needs.
The 330 uF capacitor across the voltage source is there to help smooth out any minor voltage fluctuations. Since I'm using an old computer power supply, this is not necessary, but I left it in just in case someone wants to use a 5 volt wall adapter to power their cube.
Each A6276EA controller chip has 16 outputs. I didn't have any other suitable connector so I soldered leads to some 16 pin IC sockets and will use those to connect the controller board to the cube. I also cut an IC socket in half and used it to connect the 8 wires that connect the transistors to the layers of the cube.
I cut about 5 inches off the end of an old floppy cable to use as the connector for the Arduino. The floppy cable is 2 rows of 20 pins, the bare Bones Board has 18 pins. This is a very cheap way (free) to connect the Arduino to the board. I pulled the ribbon cable apart in groups of 2 wires, stripped the ends and soldered them together. This allows you to plug the Arduino into either row of the connector. Follow the schematic and solder the connector into place. Don't forget to solder the 5 volt and ground leads for the connector to provide power to the Arduino.
I intend to use this controller board for other projects so the modular design works nicely for me. If you want to hard-wire the connections, that is fine.
Follow the schematic and build the board however you choose. I placed the controller chips in the center of the board and use the left side to hold the transistors that control the current to each layer of the cube, and used the right side to hold the connectors that go from the controller chips to the cathodes of the LED columns.
I found an old 40mm computer fan with a female molex connector to plug it into a computer power supply. This was perfect. A small amount of air flow across the chip is useful and I now have an easy way to provide 5 volts to the controller chips and the Arduino itself.
On the schematic, RC is the current limiting resistor for all the LEDs connected to each A6276EA. I used 1000 ohms because it provides 5 milliamps to the LED, enough to light it. I'm using High Brightness, not Super Brite LEDs, so current drain is lower. If all 8 LEDs in a column are lit at once, it's only 40 milliamps. Each output of the A6276EA can handle 90 milliamps so I am well within range.
RL is the resistor connected to the logic or signal leads. The actual value is not very important as long as it exists and is not too large. I'm using 560 ohms because I had a bunch of them available.
I used a power transistor capable of handling up to 6 amps to control the current going to each layer of the cube. This is overkill for this project, as each layer of the cube will only draw 320 milliamps with all the LEDs lit. I wanted room to grow and might use the controller board for something bigger later. Use whatever size transistor fits your needs.
The 330 uF capacitor across the voltage source is there to help smooth out any minor voltage fluctuations. Since I'm using an old computer power supply, this is not necessary, but I left it in just in case someone wants to use a 5 volt wall adapter to power their cube.
Each A6276EA controller chip has 16 outputs. I didn't have any other suitable connector so I soldered leads to some 16 pin IC sockets and will use those to connect the controller board to the cube. I also cut an IC socket in half and used it to connect the 8 wires that connect the transistors to the layers of the cube.
I cut about 5 inches off the end of an old floppy cable to use as the connector for the Arduino. The floppy cable is 2 rows of 20 pins, the bare Bones Board has 18 pins. This is a very cheap way (free) to connect the Arduino to the board. I pulled the ribbon cable apart in groups of 2 wires, stripped the ends and soldered them together. This allows you to plug the Arduino into either row of the connector. Follow the schematic and solder the connector into place. Don't forget to solder the 5 volt and ground leads for the connector to provide power to the Arduino.
I intend to use this controller board for other projects so the modular design works nicely for me. If you want to hard-wire the connections, that is fine.
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Oct 22, 2010. 12:49 AM
Deep C
says:
Deep C
says:
If I went with common cathode, I think I could just modify the schematic from the other one using NPN transistors instead without modifying the code. I understand electronics pretty well, But I'm just learning arduino code and would like a jumping off point. I think that would be the only modification necessary. Anything anyone else can see I'd need to change?
Reply
Nov 8, 2010. 2:28 PMArikel
says:
Other than grounding the transistors instead of using 5V, you will need to find a new LED Driver. The one listed will not provide power.
Reply
Oct 23, 2010. 2:54 AMDeep C
says:
Deep C
says:
Someone else had a different way of wireing it if I remember correctly it used only 1 output for the eight layers I'lltry to find it and post a link or schematic
Reply
Aug 13, 2010. 6:48 AMkupa1416
says:
El servicio npn PUEDE C1008 voi un probarlo i les digo Como FUE
Reply
2
Jul 20, 2009. 10:57 PMPAKIS-RULEZ
says:
BRO CAN U PUT A HI RES PICture for the circuit thanks in advance!! the pic is blurry iam buying the parts to make this thing.
Reply
Feb 16, 2010. 7:48 PM13r1an
says:
click on the [ i ] on the upper left of the picture to view it in the original resolution.
Reply
Sep 2, 2009. 8:16 PManchormansam
says:
Can you please tell me what exact NPN transistors to purchase? I want to make sure that i can get this to work perfect
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