Other Projects > Desktop CNC - 3 Axis Stepper Controller

Finished 3 Axis Controller

Finished 3 Axis ULN2803A Controller

ULN2803 2 Axis Controller Schematic

ULN2803A 3 Axis Controller Schematic

Circuit used: This ciricuit is a compilation of many different sources found on the internet. You may have noticed that I am running 1 inuput through 2 inputs on the ULN2308A. This will allow me to drive motors up to 1A on a single chip. The motors I am using don't require it, but I thought it might be prudent to over engineer it a bit. I added a power jack, to use a 12V DC 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, header pins, and 3 DB9 female connectors

Construction Notes:I used my toner transfer method to make the circuit board. AND keep your bench clean! See the pictures below.

Programming: I finally got Turbo CNC figured out and moving all of the motors like it should. I am so happy that I figured out what happened. I had inadvertently misswired the 3rd axis from the parallel port break out to the circuit board.


3 Axis Controller Complete

Final Notes: I am I am now designing the mechanical layout for the Desktop CNC rig. Check out the photos below...

Toner Transfer Done
Here it the trace that I shorted with a bit of wire that was left on my bench.
TT Bottom
Toner Transfer Done
Etched and Drilled
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. Additionally, this was the first version of the board. I moved the labels for the X-Y-Z ouptuts to the inside and trimmed the edge of the board.
3 Axis Controller

Here it is fully popluated, after the minor re-design. Note the out labels on the backside of the DB9 connectors.
Stepper Cabled
Stepper motor with cabling and DB9 male connector.
Etched and Drilled
Here are the specs on the steppers I am going to use. They run great off of a 12V wallwart. I may need a bit more power once it is actually driving a load.


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