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Finished 2 Axis Controller

Finished 2 Axis ULN2803A Controller

ULN2803 2 Axis Controller Schematic

ULN2803 2 Axis Controller Schematic

Circuit used: This ciricuit is a compilation of many different sources found on the internet. I added a power jack, to use wallwart power and a power on LED. Download the Diptrace files here. You can find the Diptrace program here. They also have excellent support (even for us free users) on their Diptrace Yahoo Group.

Parts List: ULN2803 (datasheet),1N4001 Diode (datasheet), LED, 330 ohm resistor, and header pins

Construction Notes:I used my toner transfer method to make the circuit board.

Programming: You can get the programs from various places on the internet. I have a copy of TurboCNC, a dos based program. However, I have only gotten one axis set up properly, and haven't had the time to sort out the second axis yet. So, I relied on the old standby QBasic from Microsoft. It is no longer supported and can be found and downloaded from several places. I got my copy from PhatCode, and if you are into programming at all, I suggest you check out thier site. You can either just put a meter on the output pins or hook the output to an LED to test, as I did.

Since we are only using Pins 2-9, and my LPT port is set to 378h (888 in Qbasic) in the BIOS, I only need the basic command to use is OUT 888, PinValue (OUT 888, 1 -- Turns on Pin 1)

  • Pin # Value
  • 2 1
  • 3 2
  • 4 4
  • 5 8
  • 6 16
  • 7 32
  • 8 64
  • 9 128

Here is my test rig. I connected power from the controller to the breadboard and the ground as well. This way I could turn on each LED and verify the circuit.


Final Notes: I am working on the final 3 axis version as we speak. However, I want to sort out the TurboCNC issues first.

Etched and Drilled
Etched and drilled PCB. Turned out rather well.
Top SilkMask
I did elongate the pads for the 1N4001 diodes. The wire used on the diodes that I have is rather thick and there wouldn't have been much pad left after drilling. I did not modify the pattern, only the layout.


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